Merge remote-tracking branch 'upstream/master'

25 files changed, 4533 insertions, 1169 deletions

diff --git a/src/build_settings.cpp b/src/build_settings.cpp
index 992443f7c..5d1c07a67 100644
--- a/src/build_settings.cpp
+++ b/src/build_settings.cpp
@@ -2,7 +2,7 @@ enum TargetOsKind {
 	TargetOs_Invalid,
 
 	TargetOs_windows,
-	TargetOs_osx,
+	TargetOs_darwin,
 	TargetOs_linux,
 	TargetOs_essence,
 
@@ -30,7 +30,7 @@ enum TargetEndianKind {
 String target_os_names[TargetOs_COUNT] = {
 	str_lit(""),
 	str_lit("windows"),
-	str_lit("osx"),
+	str_lit("darwin"),
 	str_lit("linux"),
 	str_lit("essence"),
 };
@@ -55,9 +55,7 @@ TargetEndianKind target_endians[TargetArch_COUNT] = {
 
 
 
-String const ODIN_VERSION = str_lit("0.10.1");
-String cross_compile_target = str_lit("");
-String cross_compile_lib_dir = str_lit("");
+String const ODIN_VERSION = str_lit("0.10.2");
 
 
 
@@ -66,6 +64,7 @@ struct TargetMetrics {
 	TargetArchKind arch;
 	isize          word_size;
 	isize          max_align;
+	String         target_triplet;
 };
 
 
@@ -109,6 +108,7 @@ struct BuildContext {
 	bool   has_resource;
 	String opt_flags;
 	String llc_flags;
+	String target_triplet;
 	String link_flags;
 	bool   is_dll;
 	bool   generate_docs;
@@ -121,6 +121,7 @@ struct BuildContext {
 	bool   no_crt;
 	bool   use_lld;
 	bool   vet;
+	bool   cross_compiling;
 
 	QueryDataSetSettings query_data_set_settings;
 
@@ -135,18 +136,19 @@ struct BuildContext {
 gb_global BuildContext build_context = {0};
 
 
-
 gb_global TargetMetrics target_windows_386 = {
 	TargetOs_windows,
 	TargetArch_386,
 	4,
 	8,
+	str_lit("i686-pc-windows"),
 };
 gb_global TargetMetrics target_windows_amd64 = {
 	TargetOs_windows,
 	TargetArch_amd64,
 	8,
 	16,
+	str_lit("x86_64-pc-windows-gnu"),
 };
 
 gb_global TargetMetrics target_linux_386 = {
@@ -154,23 +156,47 @@ gb_global TargetMetrics target_linux_386 = {
 	TargetArch_386,
 	4,
 	8,
+	str_lit("i686-pc-linux-gnu"),
 };
 gb_global TargetMetrics target_linux_amd64 = {
 	TargetOs_linux,
 	TargetArch_amd64,
 	8,
 	16,
+	str_lit("x86_64-pc-linux-gnu"),
+};
+
+gb_global TargetMetrics target_darwin_amd64 = {
+	TargetOs_darwin,
+	TargetArch_amd64,
+	8,
+	16,
+	str_lit("x86_64-apple-darwin"),
 };
 
-gb_global TargetMetrics target_osx_amd64 = {
-	TargetOs_osx,
+gb_global TargetMetrics target_essence_amd64 = {
+	TargetOs_essence,
 	TargetArch_amd64,
 	8,
 	16,
+	str_lit("x86_64-pc-none-elf"),
 };
 
+struct NamedTargetMetrics {
+	String name;
+	TargetMetrics *metrics;
+};
 
+gb_global NamedTargetMetrics named_targets[] = {
+	{ str_lit("essence_amd64"), &target_essence_amd64 },
+	{ str_lit("darwin_amd64"),   &target_darwin_amd64 },
+	{ str_lit("linux_386"),     &target_linux_386 },
+	{ str_lit("linux_amd64"),   &target_linux_amd64 },
+	{ str_lit("windows_386"),   &target_windows_386 },
+	{ str_lit("windows_amd64"), &target_windows_amd64 },
+};
 
+NamedTargetMetrics *selected_target_metrics;
 
 TargetOsKind get_target_os_from_string(String str) {
 	for (isize i = 0; i < TargetOs_COUNT; i++) {
@@ -522,7 +548,7 @@ String get_fullpath_core(gbAllocator a, String path) {
 
 
 
-void init_build_context(void) {
+void init_build_context(TargetMetrics *cross_target) {
 	BuildContext *bc = &build_context;
 
 	gb_affinity_init(&bc->affinity);
@@ -540,7 +566,7 @@ void init_build_context(void) {
 		#if defined(GB_SYSTEM_WINDOWS)
 			metrics = target_windows_amd64;
 		#elif defined(GB_SYSTEM_OSX)
-			metrics = target_osx_amd64;
+			metrics = target_darwin_amd64;
 		#else
 			metrics = target_linux_amd64;
 		#endif
@@ -554,8 +580,9 @@ void init_build_context(void) {
 		#endif
 	#endif
 
-	if (cross_compile_target.len) {
-		bc->ODIN_OS = cross_compile_target;
+	if (cross_target) {
+		metrics = *cross_target;
+		bc->cross_compiling = true;
 	}
 
 	GB_ASSERT(metrics.os != TargetOs_Invalid);
@@ -573,6 +600,7 @@ void init_build_context(void) {
 	bc->max_align   = metrics.max_align;
 	bc->link_flags  = str_lit(" ");
 	bc->opt_flags   = str_lit(" ");
+	bc->target_triplet = metrics.target_triplet;
 
 
 	gbString llc_flags = gb_string_make_reserve(heap_allocator(), 64);
@@ -590,7 +618,7 @@ void init_build_context(void) {
 		case TargetOs_windows:
 			bc->link_flags = str_lit("/machine:x64 ");
 			break;
-		case TargetOs_osx:
+		case TargetOs_darwin:
 			break;
 		case TargetOs_linux:
 			bc->link_flags = str_lit("-arch x86-64 ");
@@ -603,7 +631,7 @@ void init_build_context(void) {
 		case TargetOs_windows:
 			bc->link_flags = str_lit("/machine:x86 ");
 			break;
-		case TargetOs_osx:
+		case TargetOs_darwin:
 			gb_printf_err("Unsupported architecture\n");
 			gb_exit(1);
 			break;
diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 1a6fad918..ebfc29899 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -41,11 +41,20 @@ Type *check_init_variable(CheckerContext *ctx, Entity *e, Operand *operand, Stri
 	}
 
 	if (operand->mode == Addressing_Type) {
-		gbString t = type_to_string(operand->type);
-		error(operand->expr, "Cannot assign a type '%s' to variable '%.*s'", t, LIT(e->token.string));
-		gb_string_free(t);
-		e->type = operand->type;
-		return nullptr;
+		if (e->type != nullptr && is_type_typeid(e->type)) {
+			add_type_info_type(ctx, operand->type);
+			add_type_and_value(ctx->info, operand->expr, Addressing_Value, e->type, exact_value_typeid(operand->type));
+			return e->type;
+		} else {
+			gbString t = type_to_string(operand->type);
+			defer (gb_string_free(t));
+			error(operand->expr, "Cannot assign a type '%s' to variable '%.*s'", t, LIT(e->token.string));
+			if (e->type == nullptr) {
+				error_line("\tThe type of the variable '%.*s' cannot be inferred as a type does not have a type\n", LIT(e->token.string));
+			}
+			e->type = operand->type;
+			return nullptr;
+		}
 	}
 
 
@@ -112,7 +121,8 @@ void check_init_variables(CheckerContext *ctx, Entity **lhs, isize lhs_count, Ar
 	isize rhs_count = operands.count;
 	for_array(i, operands) {
 		if (operands[i].mode == Addressing_Invalid) {
-			rhs_count--;
+			// TODO(bill): Should I ignore invalid parameters?
+			// rhs_count--;
 		}
 	}
 
@@ -239,7 +249,7 @@ isize total_attribute_count(DeclInfo *decl) {
 }
 
 
-void check_type_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Type *def) {
+void check_type_decl(CheckerContext *ctx, Entity *e, Ast *init_expr, Type *def) {
 	GB_ASSERT(e->type == nullptr);
 
 	DeclInfo *decl = decl_info_of_entity(e);
@@ -247,9 +257,8 @@ void check_type_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Type *def)
 		check_decl_attributes(ctx, decl->attributes, const_decl_attribute, nullptr);
 	}
 
-
-	bool is_distinct = is_type_distinct(type_expr);
-	Ast *te = remove_type_alias_clutter(type_expr);
+	bool is_distinct = is_type_distinct(init_expr);
+	Ast *te = remove_type_alias_clutter(init_expr);
 	e->type = t_invalid;
 	String name = e->token.string;
 	Type *named = alloc_type_named(name, nullptr, e);
@@ -265,7 +274,7 @@ void check_type_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Type *def)
 	named->Named.base = base_type(bt);
 
 	if (is_distinct && is_type_typeid(e->type)) {
-		error(type_expr, "'distinct' cannot be applied to 'typeid'");
+		error(init_expr, "'distinct' cannot be applied to 'typeid'");
 		is_distinct = false;
 	}
 	if (!is_distinct) {
@@ -274,6 +283,19 @@ void check_type_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Type *def)
 		e->TypeName.is_type_alias = true;
 	}
 
+
+	if (decl->type_expr != nullptr) {
+		Type *t = check_type(ctx, decl->type_expr);
+		if (t != nullptr && !is_type_typeid(t)) {
+			Operand operand = {};
+			operand.mode = Addressing_Type;
+			operand.type = e->type;
+			operand.expr = init_expr;
+			check_assignment(ctx, &operand, t, str_lit("constant declaration"));
+		}
+	}
+
+
 	// using decl
 	if (decl->is_using) {
 		// NOTE(bill): Must be an enum declaration
@@ -362,15 +384,14 @@ void check_const_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init,
 
 		switch (operand.mode) {
 		case Addressing_Type: {
+			if (e->type != nullptr && !is_type_typeid(e->type)) {
+				check_assignment(ctx, &operand, e->type, str_lit("constant declaration"));
+			}
+
 			e->kind = Entity_TypeName;
 			e->type = nullptr;
 
-			DeclInfo *d = ctx->decl;
-			if (d->type_expr != nullptr) {
-				error(e->token, "A type declaration cannot have an type parameter");
-			}
-			d->type_expr = d->init_expr;
-			check_type_decl(ctx, e, d->type_expr, named_type);
+			check_type_decl(ctx, e, ctx->decl->init_expr, named_type);
 			return;
 		}
 
@@ -654,7 +675,6 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 
 	bool is_foreign         = e->Procedure.is_foreign;
 	bool is_export          = e->Procedure.is_export;
-	bool is_require_results = (pl->tags & ProcTag_require_results) != 0;
 
 	if (e->pkg != nullptr && e->token.string == "main") {
 		if (pt->param_count != 0 ||
@@ -714,10 +734,10 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 		}
 	}
 
-	if (pt->result_count == 0 && is_require_results) {
-		error(pl->type, "'#require_results' is not needed on a procedure with no results");
+	if (pt->result_count == 0 && ac.require_results) {
+		error(pl->type, "'require_results' is not needed on a procedure with no results");
 	} else {
-		pt->require_results = is_require_results;
+		pt->require_results = ac.require_results;
 	}
 
 	if (ac.link_name.len > 0) {
@@ -791,7 +811,7 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 	}
 }
 
-void check_var_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init_expr) {
+void check_global_variable_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init_expr) {
 	GB_ASSERT(e->type == nullptr);
 	GB_ASSERT(e->kind == Entity_Variable);
 
@@ -805,6 +825,7 @@ void check_var_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init_ex
 	ac.init_expr_list_count = init_expr != nullptr ? 1 : 0;
 
 	DeclInfo *decl = decl_info_of_entity(e);
+	GB_ASSERT(decl == ctx->decl);
 	if (decl != nullptr) {
 		check_decl_attributes(ctx, decl->attributes, var_decl_attribute, &ac);
 	}
@@ -936,7 +957,6 @@ void check_proc_group_decl(CheckerContext *ctx, Entity *pg_entity, DeclInfo *d)
 
 	ptr_set_destroy(&entity_set);
 
-
 	for_array(j, pge->entities) {
 		Entity *p = pge->entities[j];
 		if (p->type == t_invalid) {
@@ -962,27 +982,40 @@ void check_proc_group_decl(CheckerContext *ctx, Entity *pg_entity, DeclInfo *d)
 			defer (end_error_block());
 
 			ProcTypeOverloadKind kind = are_proc_types_overload_safe(p->type, q->type);
-			switch (kind) {
+			bool both_have_where_clauses = false;
+			if (p->decl_info->proc_lit != nullptr && q->decl_info->proc_lit != nullptr) {
+				GB_ASSERT(p->decl_info->proc_lit->kind == Ast_ProcLit);
+				GB_ASSERT(q->decl_info->proc_lit->kind == Ast_ProcLit);
+				auto pl = &p->decl_info->proc_lit->ProcLit;
+				auto ql = &q->decl_info->proc_lit->ProcLit;
+
+				// Allow collisions if the procedures both have 'where' clauses and are both polymorphic
+				bool pw = pl->where_token.kind != Token_Invalid && is_type_polymorphic(p->type, true);
+				bool qw = ql->where_token.kind != Token_Invalid && is_type_polymorphic(q->type, true);
+				both_have_where_clauses = pw && qw;
+			}
+
+			if (!both_have_where_clauses) switch (kind) {
 			case ProcOverload_Identical:
-				error(p->token, "Overloaded procedure '%.*s' as the same type as another procedure in this scope", LIT(name));
+				error(p->token, "Overloaded procedure '%.*s' as the same type as another procedure in the procedure group '%.*s'", LIT(name), LIT(proc_group_name));
 				is_invalid = true;
 				break;
 			// case ProcOverload_CallingConvention:
-				// error(p->token, "Overloaded procedure '%.*s' as the same type as another procedure in this scope", LIT(name));
+				// error(p->token, "Overloaded procedure '%.*s' as the same type as another procedure in the procedure group '%.*s'", LIT(name), LIT(proc_group_name));
 				// is_invalid = true;
 				// break;
 			case ProcOverload_ParamVariadic:
-				error(p->token, "Overloaded procedure '%.*s' as the same type as another procedure in this scope", LIT(name));
+				error(p->token, "Overloaded procedure '%.*s' as the same type as another procedure in the procedure group '%.*s'", LIT(name), LIT(proc_group_name));
 				is_invalid = true;
 				break;
 			case ProcOverload_ResultCount:
 			case ProcOverload_ResultTypes:
-				error(p->token, "Overloaded procedure '%.*s' as the same parameters but different results in this scope", LIT(name));
+				error(p->token, "Overloaded procedure '%.*s' as the same parameters but different results in the procedure group '%.*s'", LIT(name), LIT(proc_group_name));
 				is_invalid = true;
 				break;
 			case ProcOverload_Polymorphic:
 				#if 0
-				error(p->token, "Overloaded procedure '%.*s' has a polymorphic counterpart in this scope which is not allowed", LIT(name));
+				error(p->token, "Overloaded procedure '%.*s' has a polymorphic counterpart in the procedure group '%.*s' which is not allowed", LIT(name), LIT(proc_group_name));
 				is_invalid = true;
 				#endif
 				break;
@@ -1051,13 +1084,13 @@ void check_entity_decl(CheckerContext *ctx, Entity *e, DeclInfo *d, Type *named_
 
 	switch (e->kind) {
 	case Entity_Variable:
-		check_var_decl(&c, e, d->type_expr, d->init_expr);
+		check_global_variable_decl(&c, e, d->type_expr, d->init_expr);
 		break;
 	case Entity_Constant:
 		check_const_decl(&c, e, d->type_expr, d->init_expr, named_type);
 		break;
 	case Entity_TypeName: {
-		check_type_decl(&c, e, d->type_expr, named_type);
+		check_type_decl(&c, e, d->init_expr, named_type);
 		break;
 	}
 	case Entity_Procedure:
@@ -1074,6 +1107,11 @@ void check_entity_decl(CheckerContext *ctx, Entity *e, DeclInfo *d, Type *named_
 }
 
 
+struct ProcUsingVar {
+	Entity *e;
+	Entity *uvar;
+};
+
 
 void check_proc_body(CheckerContext *ctx_, Token token, DeclInfo *decl, Type *type, Ast *body) {
 	if (body == nullptr) {
@@ -1098,76 +1136,117 @@ void check_proc_body(CheckerContext *ctx_, Token token, DeclInfo *decl, Type *ty
 	ctx->curr_proc_decl = decl;
 	ctx->curr_proc_sig  = type;
 
-	GB_ASSERT(type->kind == Type_Proc);
-	if (type->Proc.param_count > 0) {
-		TypeTuple *params = &type->Proc.params->Tuple;
-		for_array(i, params->variables) {
-			Entity *e = params->variables[i];
-			if (e->kind != Entity_Variable) {
-				continue;
-			}
-			if (!(e->flags & EntityFlag_Using)) {
-				continue;
-			}
-			bool is_immutable = e->Variable.is_immutable;
-			bool is_value     = (e->flags & EntityFlag_Value) != 0 && !is_type_pointer(e->type);
-			String name = e->token.string;
-			Type *t = base_type(type_deref(e->type));
-			if (t->kind == Type_Struct) {
-				Scope *scope = t->Struct.scope;
-				if (scope == nullptr) {
-					scope = scope_of_node(t->Struct.node);
+	ast_node(bs, BlockStmt, body);
+
+	Array<ProcUsingVar> using_entities = {};
+	using_entities.allocator = heap_allocator();
+	defer (array_free(&using_entities));
+
+	{
+		GB_ASSERT(type->kind == Type_Proc);
+		if (type->Proc.param_count > 0) {
+			TypeTuple *params = &type->Proc.params->Tuple;
+			for_array(i, params->variables) {
+				Entity *e = params->variables[i];
+				if (e->kind != Entity_Variable) {
+					continue;
+				}
+				if (!(e->flags & EntityFlag_Using)) {
+					continue;
 				}
-				GB_ASSERT(scope != nullptr);
-				for_array(i, scope->elements.entries) {
-					Entity *f = scope->elements.entries[i].value;
-					if (f->kind == Entity_Variable) {
-						Entity *uvar = alloc_entity_using_variable(e, f->token, f->type);
-						uvar->Variable.is_immutable = is_immutable;
-						if (is_value) uvar->flags |= EntityFlag_Value;
-
-						Entity *prev = scope_insert(ctx->scope, uvar);
-						if (prev != nullptr) {
-							error(e->token, "Namespace collision while 'using' '%.*s' of: %.*s", LIT(name), LIT(prev->token.string));
-							break;
+				bool is_immutable = e->Variable.is_immutable;
+				bool is_value     = (e->flags & EntityFlag_Value) != 0 && !is_type_pointer(e->type);
+				String name = e->token.string;
+				Type *t = base_type(type_deref(e->type));
+				if (t->kind == Type_Struct) {
+					Scope *scope = t->Struct.scope;
+					if (scope == nullptr) {
+						scope = scope_of_node(t->Struct.node);
+					}
+					GB_ASSERT(scope != nullptr);
+					for_array(i, scope->elements.entries) {
+						Entity *f = scope->elements.entries[i].value;
+						if (f->kind == Entity_Variable) {
+							Entity *uvar = alloc_entity_using_variable(e, f->token, f->type, nullptr);
+							uvar->Variable.is_immutable = is_immutable;
+							if (is_value) uvar->flags |= EntityFlag_Value;
+
+							ProcUsingVar puv = {e, uvar};
+							array_add(&using_entities, puv);
+
 						}
 					}
+				} else {
+					error(e->token, "'using' can only be applied to variables of type struct");
+					break;
 				}
-			} else {
-				error(e->token, "'using' can only be applied to variables of type struct");
-				break;
 			}
 		}
 	}
 
-	ast_node(bs, BlockStmt, body);
-	// check_open_scope(ctx, body);
-	check_stmt_list(ctx, bs->stmts, Stmt_CheckScopeDecls);
-	if (type->Proc.result_count > 0) {
-		if (!check_is_terminating(body)) {
-			if (token.kind == Token_Ident) {
-				error(bs->close, "Missing return statement at the end of the procedure '%.*s'", LIT(token.string));
-			} else {
-				// NOTE(bill): Anonymous procedure (lambda)
-				error(bs->close, "Missing return statement at the end of the procedure");
+
+	for_array(i, using_entities) {
+		Entity *e = using_entities[i].e;
+		Entity *uvar = using_entities[i].uvar;
+		Entity *prev = scope_insert(ctx->scope, uvar);
+		if (prev != nullptr) {
+			error(e->token, "Namespace collision while 'using' '%.*s' of: %.*s", LIT(e->token.string), LIT(prev->token.string));
+			break;
+		}
+	}
+
+
+	bool where_clause_ok = evaluate_where_clauses(ctx, decl->scope, &decl->proc_lit->ProcLit.where_clauses, true);
+	if (!where_clause_ok) {
+		// NOTE(bill, 2019-08-31): Don't check the body as the where clauses failed
+		return;
+	}
+
+	check_open_scope(ctx, body);
+	{
+		for_array(i, using_entities) {
+			Entity *e = using_entities[i].e;
+			Entity *uvar = using_entities[i].uvar;
+			Entity *prev = scope_insert(ctx->scope, uvar);
+			// NOTE(bill): Don't err here
+		}
+
+		check_stmt_list(ctx, bs->stmts, Stmt_CheckScopeDecls);
+
+		if (type->Proc.result_count > 0) {
+			if (!check_is_terminating(body)) {
+				if (token.kind == Token_Ident) {
+					error(bs->close, "Missing return statement at the end of the procedure '%.*s'", LIT(token.string));
+				} else {
+					// NOTE(bill): Anonymous procedure (lambda)
+					error(bs->close, "Missing return statement at the end of the procedure");
+				}
 			}
 		}
 	}
-	// check_close_scope(ctx);
+	check_close_scope(ctx);
 
 	check_scope_usage(ctx->checker, ctx->scope);
 
+#if 1
 	if (decl->parent != nullptr) {
-		// NOTE(bill): Add the dependencies from the procedure literal (lambda)
-		for_array(i, decl->deps.entries) {
-			Entity *e = decl->deps.entries[i].ptr;
-			ptr_set_add(&decl->parent->deps, e);
-		}
-		for_array(i, decl->type_info_deps.entries) {
-			Type *t = decl->type_info_deps.entries[i].ptr;
-			ptr_set_add(&decl->parent->type_info_deps, t);
+		Scope *ps = decl->parent->scope;
+		if (ps->flags & (ScopeFlag_File & ScopeFlag_Pkg & ScopeFlag_Global)) {
+			return;
+		} else {
+			// NOTE(bill): Add the dependencies from the procedure literal (lambda)
+			// But only at the procedure level
+			for_array(i, decl->deps.entries) {
+				Entity *e = decl->deps.entries[i].ptr;
+				ptr_set_add(&decl->parent->deps, e);
+			}
+			for_array(i, decl->type_info_deps.entries) {
+				Type *t = decl->type_info_deps.entries[i].ptr;
+				ptr_set_add(&decl->parent->type_info_deps, t);
+			}
 		}
 	}
+#endif
 }
 
 
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 4c5ca2348..fae38fa01 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -62,7 +62,7 @@ Type *   make_optional_ok_type          (Type *value);
 void     check_type_decl                (CheckerContext *c, Entity *e, Ast *type_expr, Type *def);
 Entity * check_selector                 (CheckerContext *c, Operand *operand, Ast *node, Type *type_hint);
 Entity * check_ident                    (CheckerContext *c, Operand *o, Ast *n, Type *named_type, Type *type_hint, bool allow_import_name);
-Entity * find_polymorphic_record_entity (CheckerContext *c, Type *original_type, isize param_count, Array<Operand> ordered_operands);
+Entity * find_polymorphic_record_entity (CheckerContext *c, Type *original_type, isize param_count, Array<Operand> const &ordered_operands, bool *failure);
 void     check_not_tuple                (CheckerContext *c, Operand *operand);
 void     convert_to_typed               (CheckerContext *c, Operand *operand, Type *target_type);
 gbString expr_to_string                 (Ast *expression);
@@ -89,8 +89,8 @@ Type *           check_init_variable    (CheckerContext *c, Entity *e, Operand *
 Type *type_to_abi_compat_param_type(gbAllocator a, Type *original_type, ProcCallingConvention cc);
 Type *type_to_abi_compat_result_type(gbAllocator a, Type *original_type, ProcCallingConvention cc);
 bool abi_compat_return_by_pointer(gbAllocator a, ProcCallingConvention cc, Type *abi_return_type);
-void set_procedure_abi_types(CheckerContext *c, Type *type);
-
+void set_procedure_abi_types(gbAllocator a, Type *type);
+void check_assignment_error_suggestion(CheckerContext *c, Operand *o, Type *type);
 
 Entity *entity_from_expr(Ast *expr) {
 	expr = unparen_expr(expr);
@@ -159,7 +159,7 @@ isize check_is_assignable_to_using_subtype(Type *src, Type *dst, isize level = 0
 	src = base_type(src);
 
 	if (!is_type_struct(src)) {
-		return false;
+		return 0;
 	}
 
 	for_array(i, src->Struct.fields) {
@@ -442,6 +442,10 @@ i64 check_distance_between_types(CheckerContext *c, Operand *operand, Type *type
 	}
 
 	if (operand->mode == Addressing_Type) {
+		if (is_type_typeid(type)) {
+			add_type_info_type(c, operand->type);
+			return 4;
+		}
 		return -1;
 	}
 
@@ -497,6 +501,14 @@ i64 check_distance_between_types(CheckerContext *c, Operand *operand, Type *type
 							if (is_type_complex(dst)) {
 								return 1;
 							}
+							if (is_type_quaternion(dst)) {
+								return 2;
+							}
+							break;
+						case Basic_UntypedQuaternion:
+							if (is_type_quaternion(dst)) {
+								return 1;
+							}
 							break;
 						}
 					}
@@ -664,17 +676,6 @@ void check_assignment(CheckerContext *c, Operand *operand, Type *type, String co
 		return;
 	}
 
-	#if 0
-	if (operand->mode == Addressing_Type) {
-		Type *t = base_type(type);
-		if (t->kind == Type_Pointer &&
-		    t->Pointer.elem == t_type_info) {
-			add_type_info_type(c, type);
-			return;
-		}
-	}
-	#endif
-
 	if (is_type_untyped(operand->type)) {
 		Type *target_type = type;
 		if (type == nullptr || is_type_any(type)) {
@@ -747,7 +748,12 @@ void check_assignment(CheckerContext *c, Operand *operand, Type *type, String co
 		return;
 	}
 
-	if (!check_is_assignable_to(c, operand, type)) {
+	if (check_is_assignable_to(c, operand, type)) {
+		if (operand->mode == Addressing_Type && is_type_typeid(type)) {
+			add_type_info_type(c, operand->type);
+			add_type_and_value(c->info, operand->expr, Addressing_Value, type, exact_value_typeid(operand->type));
+		}
+	} else {
 		gbString expr_str    = expr_to_string(operand->expr);
 		gbString op_type_str = type_to_string(operand->type);
 		gbString type_str    = type_to_string(type);
@@ -778,6 +784,7 @@ void check_assignment(CheckerContext *c, Operand *operand, Type *type, String co
 			      op_type_str,
 			      type_str,
 			      LIT(context_name));
+				check_assignment_error_suggestion(c, operand, type);
 			break;
 		}
 		operand->mode = Addressing_Invalid;
@@ -956,7 +963,7 @@ bool is_polymorphic_type_assignable(CheckerContext *c, Type *poly, Type *source,
 			}
 
 			if (modify_type) {
-				set_procedure_abi_types(c, source);
+				set_procedure_abi_types(c->allocator, source);
 			}
 
 			return true;
@@ -1438,7 +1445,7 @@ bool check_representable_as_constant(CheckerContext *c, ExactValue in_value, Typ
 			ExactValue imag = exact_value_imag(v);
 			if (real.kind != ExactValue_Invalid &&
 			    imag.kind != ExactValue_Invalid) {
-				if (out_value) *out_value = exact_binary_operator_value(Token_Add, real, exact_value_make_imag(imag));
+				if (out_value) *out_value = exact_value_complex(exact_value_to_f64(real), exact_value_to_f64(imag));
 				return true;
 			}
 			break;
@@ -1450,6 +1457,36 @@ bool check_representable_as_constant(CheckerContext *c, ExactValue in_value, Typ
 		}
 
 		return false;
+	} else if (is_type_quaternion(type)) {
+		ExactValue v = exact_value_to_quaternion(in_value);
+		if (v.kind != ExactValue_Quaternion) {
+			return false;
+		}
+
+		switch (type->Basic.kind) {
+		case Basic_quaternion128:
+		case Basic_quaternion256: {
+			ExactValue real = exact_value_real(v);
+			ExactValue imag = exact_value_imag(v);
+			ExactValue jmag = exact_value_jmag(v);
+			ExactValue kmag = exact_value_kmag(v);
+			if (real.kind != ExactValue_Invalid &&
+			    imag.kind != ExactValue_Invalid) {
+				if (out_value) *out_value = exact_value_quaternion(exact_value_to_f64(real), exact_value_to_f64(imag), exact_value_to_f64(jmag), exact_value_to_f64(kmag));
+				return true;
+			}
+			break;
+		}
+		case Basic_UntypedComplex:
+			if (out_value) *out_value = exact_value_to_quaternion(*out_value);
+			return true;
+		case Basic_UntypedQuaternion:
+			return true;
+
+		default: GB_PANIC("Compiler error: Unknown complex type!"); break;
+		}
+
+		return false;
 	} else if (is_type_pointer(type)) {
 		if (in_value.kind == ExactValue_Pointer) {
 			return true;
@@ -1471,28 +1508,97 @@ bool check_representable_as_constant(CheckerContext *c, ExactValue in_value, Typ
 	return false;
 }
 
+
+void check_assignment_error_suggestion(CheckerContext *c, Operand *o, Type *type) {
+	gbString a = expr_to_string(o->expr);
+	gbString b = type_to_string(type);
+	defer(
+		gb_string_free(b);
+		gb_string_free(a);
+	);
+
+	Type *src = base_type(o->type);
+	Type *dst = base_type(type);
+
+	if (is_type_array(src) && is_type_slice(dst)) {
+		Type *s = src->Array.elem;
+		Type *d = dst->Slice.elem;
+		if (are_types_identical(s, d)) {
+			error_line("\tSuggestion: the array expression may be sliced with %s[:]\n", a);
+		}
+	} else if (are_types_identical(src, dst)) {
+		error_line("\tSuggestion: the expression may be directly casted to type %s\n", b);
+	} else if (are_types_identical(src, t_string) && is_type_u8_slice(dst)) {
+		error_line("\tSuggestion: a string may be casted to %s\n", a, b);
+	} else if (is_type_u8_slice(src) && are_types_identical(dst, t_string)) {
+		error_line("\tSuggestion: the expression may be casted to %s\n", b);
+	}
+}
+
+void check_cast_error_suggestion(CheckerContext *c, Operand *o, Type *type) {
+	gbString a = expr_to_string(o->expr);
+	gbString b = type_to_string(type);
+	defer(
+		gb_string_free(b);
+		gb_string_free(a);
+	);
+
+	Type *src = base_type(o->type);
+	Type *dst = base_type(type);
+
+	if (is_type_array(src) && is_type_slice(dst)) {
+		Type *s = src->Array.elem;
+		Type *d = dst->Slice.elem;
+		if (are_types_identical(s, d)) {
+			error_line("\tSuggestion: the array expression may be sliced with %s[:]\n", a);
+		}
+	} else if (is_type_pointer(o->type) && is_type_integer(type)) {
+		if (is_type_uintptr(type)) {
+			error_line("\tSuggestion: a pointer may be directly casted to %s\n", b);
+		} else {
+			error_line("\tSuggestion: for a pointer to be casted to an integer, it must be converted to 'uintptr' first\n");
+			i64 x = type_size_of(o->type);
+			i64 y = type_size_of(type);
+			if (x != y) {
+				error_line("\tNote: the type of expression and the type of the cast have a different size in bytes, %lld vs %lld\n", x, y);
+			}
+		}
+	} else if (is_type_integer(o->type) && is_type_pointer(type)) {
+		if (is_type_uintptr(o->type)) {
+			error_line("\tSuggestion: %a may be directly casted to %s\n", a, b);
+		} else {
+			error_line("\tSuggestion: for an integer to be casted to a pointer, it must be converted to 'uintptr' first\n");
+		}
+	} else if (are_types_identical(src, t_string) && is_type_u8_slice(dst)) {
+		error_line("\tSuggestion: a string may be casted to %s\n", a, b);
+	} else if (is_type_u8_slice(src) && are_types_identical(dst, t_string)) {
+		error_line("\tSuggestion: the expression may be casted to %s\n", b);
+	}
+}
+
+
 void check_is_expressible(CheckerContext *c, Operand *o, Type *type) {
-	GB_ASSERT(is_type_constant_type(type));
 	GB_ASSERT(o->mode == Addressing_Constant);
-	if (!check_representable_as_constant(c, o->value, type, &o->value)) {
+	if (!is_type_constant_type(type) || !check_representable_as_constant(c, o->value, type, &o->value)) {
 		gbString a = expr_to_string(o->expr);
 		gbString b = type_to_string(type);
+		defer(
+			gb_string_free(b);
+			gb_string_free(a);
+			o->mode = Addressing_Invalid;
+		);
+
 		if (is_type_numeric(o->type) && is_type_numeric(type)) {
 			if (!is_type_integer(o->type) && is_type_integer(type)) {
 				error(o->expr, "'%s' truncated to '%s'", a, b);
 			} else {
-				gbAllocator ha = heap_allocator();
-				String str = big_int_to_string(ha, &o->value.value_integer);
-				defer (gb_free(ha, str.text));
-				error(o->expr, "'%s = %.*s' overflows '%s'", a, LIT(str), b);
+				error(o->expr, "Cannot convert '%s' to '%s'", a, b);
+				check_assignment_error_suggestion(c, o, type);
 			}
 		} else {
 			error(o->expr, "Cannot convert '%s' to '%s'", a, b);
+			check_assignment_error_suggestion(c, o, type);
 		}
-
-		gb_string_free(b);
-		gb_string_free(a);
-		o->mode = Addressing_Invalid;
 	}
 }
 
@@ -1623,6 +1729,23 @@ void check_comparison(CheckerContext *c, Operand *x, Operand *y, TokenKind op) {
 		return;
 	}
 
+	if (x->mode == Addressing_Type && is_type_typeid(y->type)) {
+		add_type_info_type(c, x->type);
+		add_type_and_value(c->info, x->expr, Addressing_Value, y->type, exact_value_typeid(x->type));
+
+		x->mode = Addressing_Value;
+		x->type = t_untyped_bool;
+		return;
+	} else if (is_type_typeid(x->type) && y->mode == Addressing_Type) {
+		add_type_info_type(c, y->type);
+		add_type_and_value(c->info, y->expr, Addressing_Value, x->type, exact_value_typeid(y->type));
+
+		x->mode = Addressing_Value;
+		x->type = t_untyped_bool;
+		return;
+	}
+
+
 	gbString err_str = nullptr;
 
 	defer (if (err_str != nullptr) {
@@ -1759,6 +1882,21 @@ void check_comparison(CheckerContext *c, Operand *x, Operand *y, TokenKind op) {
 					}
 					break;
 				}
+			} else if (is_type_quaternion(x->type) || is_type_quaternion(y->type)) {
+				switch (op) {
+				case Token_CmpEq:
+					switch (8*size) {
+					case 128: add_package_dependency(c, "runtime", "quaternion128_eq");  break;
+					case 256: add_package_dependency(c, "runtime", "quaternion256_eq"); break;
+					}
+					break;
+				case Token_NotEq:
+					switch (8*size) {
+					case 128: add_package_dependency(c, "runtime", "quaternion128_ne");  break;
+					case 256: add_package_dependency(c, "runtime", "quaternion256_ne"); break;
+					}
+					break;
+				}
 			}
 		}
 
@@ -1767,7 +1905,7 @@ void check_comparison(CheckerContext *c, Operand *x, Operand *y, TokenKind op) {
 
 }
 
-void check_shift(CheckerContext *c, Operand *x, Operand *y, Ast *node) {
+void check_shift(CheckerContext *c, Operand *x, Operand *y, Ast *node, Type *type_hint) {
 	GB_ASSERT(node->kind == Ast_BinaryExpr);
 	ast_node(be, BinaryExpr, node);
 
@@ -1845,6 +1983,9 @@ void check_shift(CheckerContext *c, Operand *x, Operand *y, Ast *node) {
 				info->is_lhs = true;
 			}
 			x->mode = Addressing_Value;
+			if (type_hint && is_type_integer(type_hint)) {
+				x->type = type_hint;
+			}
 			// x->value = x_val;
 			return;
 		}
@@ -1975,6 +2116,14 @@ bool check_is_castable_to(CheckerContext *c, Operand *operand, Type *y) {
 		return true;
 	}
 
+	if (is_type_complex(src) && is_type_quaternion(dst)) {
+		return true;
+	}
+
+	if (is_type_quaternion(src) && is_type_quaternion(dst)) {
+		return true;
+	}
+
 	if (is_type_bit_field_value(src) && is_type_integer(dst)) {
 		return true;
 	}
@@ -2097,6 +2246,8 @@ void check_cast(CheckerContext *c, Operand *x, Type *type) {
 		gb_string_free(to_type);
 		gb_string_free(expr_str);
 
+		check_cast_error_suggestion(c, x, type);
+
 		x->mode = Addressing_Invalid;
 		return;
 	}
@@ -2167,7 +2318,7 @@ bool check_binary_array_expr(CheckerContext *c, Token op, Operand *x, Operand *y
 }
 
 
-void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, bool use_lhs_as_type_hint=false) {
+void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, Type *type_hint, bool use_lhs_as_type_hint=false) {
 	GB_ASSERT(node->kind == Ast_BinaryExpr);
 	Operand y_ = {}, *y = &y_;
 
@@ -2178,15 +2329,23 @@ void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, bool use_lhs_as
 	case Token_CmpEq:
 	case Token_NotEq: {
 		// NOTE(bill): Allow comparisons between types
-		check_expr_or_type(c, x, be->left);
+		check_expr_or_type(c, x, be->left, type_hint);
 		check_expr_or_type(c, y, be->right, x->type);
 		bool xt = x->mode == Addressing_Type;
 		bool yt = y->mode == Addressing_Type;
 		// If only one is a type, this is an error
 		if (xt ^ yt) {
 			GB_ASSERT(xt != yt);
-			if (xt) error_operand_not_expression(x);
-			if (yt) error_operand_not_expression(y);
+			if (xt) {
+				if (!is_type_typeid(y->type)) {
+					error_operand_not_expression(x);
+				}
+			}
+			if (yt) {
+				if (!is_type_typeid(x->type)) {
+					error_operand_not_expression(y);
+				}
+			}
 		}
 
 		break;
@@ -2278,11 +2437,11 @@ void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, bool use_lhs_as
 		return;
 
 	default:
-		check_expr(c, x, be->left);
+		check_expr_with_type_hint(c, x, be->left, type_hint);
 		if (use_lhs_as_type_hint) {
 			check_expr_with_type_hint(c, y, be->right, x->type);
 		} else {
-			check_expr(c, y, be->right);
+			check_expr_with_type_hint(c, y, be->right, type_hint);
 		}
 		break;
 	}
@@ -2307,7 +2466,7 @@ void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, bool use_lhs_as
 	}
 
 	if (token_is_shift(op.kind)) {
-		check_shift(c, x, y, node);
+		check_shift(c, x, y, node, type_hint);
 		return;
 	}
 
@@ -2554,6 +2713,8 @@ ExactValue convert_exact_value_for_type(ExactValue v, Type *type) {
 		v = exact_value_to_integer(v);
 	} else if (is_type_complex(t)) {
 		v = exact_value_to_complex(v);
+	} else if (is_type_quaternion(t)) {
+		v = exact_value_to_quaternion(v);
 	}
 	return v;
 }
@@ -2649,6 +2810,7 @@ void convert_to_typed(CheckerContext *c, Operand *operand, Type *target_type) {
 			case Basic_UntypedInteger:
 			case Basic_UntypedFloat:
 			case Basic_UntypedComplex:
+			case Basic_UntypedQuaternion:
 			case Basic_UntypedRune:
 				if (!is_type_numeric(target_type)) {
 					operand->mode = Addressing_Invalid;
@@ -2895,7 +3057,6 @@ Entity *check_selector(CheckerContext *c, Operand *operand, Ast *node, Type *typ
 	}
 
 	if (selector->kind != Ast_Ident) {
-	// if (selector->kind != Ast_Ident) {
 		error(selector, "Illegal selector kind: '%.*s'", LIT(ast_strings[selector->kind]));
 		operand->mode = Addressing_Invalid;
 		operand->expr = node;
@@ -3131,8 +3292,59 @@ bool check_identifier_exists(Scope *s, Ast *node, bool nested = false, Scope **o
 	return false;
 }
 
+typedef bool (BuiltinTypeIsProc)(Type *t);
+
+BuiltinTypeIsProc *builtin_type_is_procs[BuiltinProc__type_end - BuiltinProc__type_begin - 1] = {
+	nullptr, // BuiltinProc_type_base_type
+	nullptr, // BuiltinProc_type_core_type
+	nullptr, // BuiltinProc_type_elem_type
+
+	is_type_boolean,
+	is_type_integer,
+	is_type_rune,
+	is_type_float,
+	is_type_complex,
+	is_type_quaternion,
+	is_type_string,
+	is_type_typeid,
+	is_type_any,
+	is_type_endian_little,
+	is_type_endian_big,
+	is_type_numeric,
+	is_type_ordered,
+	is_type_ordered_numeric,
+	is_type_indexable,
+	is_type_sliceable,
+	is_type_simple_compare,
+	is_type_dereferenceable,
+	is_type_valid_for_keys,
+
+	is_type_named,
+	is_type_pointer,
+	is_type_opaque,
+	is_type_array,
+	is_type_slice,
+	is_type_dynamic_array,
+
+	is_type_map,
+	is_type_struct,
+	is_type_union,
+	is_type_enum,
+	is_type_proc,
+	is_type_bit_field,
+	is_type_bit_field_value,
+	is_type_bit_set,
+	is_type_simd_vector,
+
+	type_has_nil,
+
+	nullptr, // BuiltinProc_type_proc_parameter_count
+	nullptr, // BuiltinProc_type_proc_return_count
+};
+
 
-bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32 id) {
+
+bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32 id, Type *type_hint) {
 	ast_node(ce, CallExpr, call);
 	if (ce->inlining != ProcInlining_none) {
 		error(call, "Inlining operators are not allowed on built-in procedures");
@@ -3178,7 +3390,9 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		/*fallthrough*/
 	}
 	default:
-		if (ce->args.count > 0) {
+		if (BuiltinProc__type_begin < id && id < BuiltinProc__type_end) {
+			check_expr_or_type(c, operand, ce->args[0]);
+		} else if (ce->args.count > 0) {
 			check_multi_expr(c, operand, ce->args[0]);
 		}
 		break;
@@ -3306,19 +3520,43 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			if (!operand->value.value_bool) {
 				gbString arg = expr_to_string(ce->args[0]);
 				error(call, "Compile time assertion: %s", arg);
+				if (c->proc_name != "") {
+					gbString str = type_to_string(c->curr_proc_sig);
+					error_line("\tCalled within '%.*s' :: %s\n", LIT(c->proc_name), str);
+					gb_string_free(str);
+				}
 				gb_string_free(arg);
 			}
 
 			operand->type = t_untyped_bool;
 			operand->mode = Addressing_Constant;
+		} else if (name == "panic") {
+			if (ce->args.count != 1) {
+				error(call, "'#panic' expects 1 argument, got %td", ce->args.count);
+				return false;
+			}
+			if (!is_type_string(operand->type) && operand->mode != Addressing_Constant) {
+				gbString str = expr_to_string(ce->args[0]);
+				error(call, "'%s' is not a constant string", str);
+				gb_string_free(str);
+				return false;
+			}
+			error(call, "Compile time panic: %.*s", LIT(operand->value.value_string));
+			if (c->proc_name != "") {
+				gbString str = type_to_string(c->curr_proc_sig);
+				error_line("\tCalled within '%.*s' :: %s\n", LIT(c->proc_name), str);
+				gb_string_free(str);
+			}
+			operand->type = t_invalid;
+			operand->mode = Addressing_NoValue;
 		} else if (name == "defined") {
 			if (ce->args.count != 1) {
 				error(call, "'#defined' expects 1 argument, got %td", ce->args.count);
 				return false;
 			}
 			Ast *arg = unparen_expr(ce->args[0]);
-			if (arg->kind != Ast_Ident && arg->kind != Ast_SelectorExpr) {
-				error(call, "'#defined' expects an identifier or selector expression, got %s", LIT(ast_strings[arg->kind]));
+			if (arg == nullptr || (arg->kind != Ast_Ident && arg->kind != Ast_SelectorExpr)) {
+				error(call, "'#defined' expects an identifier or selector expression, got %.*s", LIT(ast_strings[arg->kind]));
 				return false;
 			}
 
@@ -3644,6 +3882,10 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		}
 		operand->mode = Addressing_Value;
 
+		if (type_hint != nullptr && check_is_castable_to(c, operand, type_hint)) {
+			operand->type = type_hint;
+		}
+
 		break;
 	}
 
@@ -3690,7 +3932,9 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		}
 
 		if (x.mode == Addressing_Constant && y.mode == Addressing_Constant) {
-			operand->value = exact_binary_operator_value(Token_Add, x.value, y.value);
+			f64 r = exact_value_to_float(x.value).value_float;
+			f64 i = exact_value_to_float(y.value).value_float;
+			operand->value = exact_value_complex(r, i);
 			operand->mode = Addressing_Constant;
 		} else {
 			operand->mode = Addressing_Value;
@@ -3705,13 +3949,109 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		default: GB_PANIC("Invalid type"); break;
 		}
 
+		if (type_hint != nullptr && check_is_castable_to(c, operand, type_hint)) {
+			operand->type = type_hint;
+		}
+
+		break;
+	}
+
+	case BuiltinProc_quaternion: {
+		// quaternion :: proc(real, imag, jmag, kmag: float_type) -> complex_type
+		Operand x = *operand;
+		Operand y = {};
+		Operand z = {};
+		Operand w = {};
+
+		// NOTE(bill): Invalid will be the default till fixed
+		operand->type = t_invalid;
+		operand->mode = Addressing_Invalid;
+
+		check_expr(c, &y, ce->args[1]);
+		if (y.mode == Addressing_Invalid) {
+			return false;
+		}
+		check_expr(c, &z, ce->args[2]);
+		if (y.mode == Addressing_Invalid) {
+			return false;
+		}
+		check_expr(c, &w, ce->args[3]);
+		if (y.mode == Addressing_Invalid) {
+			return false;
+		}
+
+		convert_to_typed(c, &x, y.type); if (x.mode == Addressing_Invalid) return false;
+		convert_to_typed(c, &y, x.type); if (y.mode == Addressing_Invalid) return false;
+		convert_to_typed(c, &z, x.type); if (z.mode == Addressing_Invalid) return false;
+		convert_to_typed(c, &w, x.type); if (w.mode == Addressing_Invalid) return false;
+		if (x.mode == Addressing_Constant &&
+		    y.mode == Addressing_Constant &&
+		    z.mode == Addressing_Constant &&
+		    w.mode == Addressing_Constant) {
+			if (is_type_numeric(x.type) && exact_value_imag(x.value).value_float == 0) {
+				x.type = t_untyped_float;
+			}
+			if (is_type_numeric(y.type) && exact_value_imag(y.value).value_float == 0) {
+				y.type = t_untyped_float;
+			}
+			if (is_type_numeric(z.type) && exact_value_imag(z.value).value_float == 0) {
+				z.type = t_untyped_float;
+			}
+			if (is_type_numeric(w.type) && exact_value_imag(w.value).value_float == 0) {
+				w.type = t_untyped_float;
+			}
+		}
+
+		if (!(are_types_identical(x.type, y.type) && are_types_identical(x.type, z.type) && are_types_identical(x.type, w.type))) {
+			gbString tx = type_to_string(x.type);
+			gbString ty = type_to_string(y.type);
+			gbString tz = type_to_string(z.type);
+			gbString tw = type_to_string(w.type);
+			error(call, "Mismatched types to 'quaternion', '%s' vs '%s' vs '%s' vs '%s'", tx, ty, tz, tw);
+			gb_string_free(tw);
+			gb_string_free(tz);
+			gb_string_free(ty);
+			gb_string_free(tx);
+			return false;
+		}
+
+		if (!is_type_float(x.type)) {
+			gbString s = type_to_string(x.type);
+			error(call, "Arguments have type '%s', expected a floating point", s);
+			gb_string_free(s);
+			return false;
+		}
+
+		if (x.mode == Addressing_Constant && y.mode == Addressing_Constant && z.mode == Addressing_Constant && w.mode == Addressing_Constant) {
+			f64 r = exact_value_to_float(x.value).value_float;
+			f64 i = exact_value_to_float(y.value).value_float;
+			f64 j = exact_value_to_float(z.value).value_float;
+			f64 k = exact_value_to_float(w.value).value_float;
+			operand->value = exact_value_quaternion(r, i, j, k);
+			operand->mode = Addressing_Constant;
+		} else {
+			operand->mode = Addressing_Value;
+		}
+
+		BasicKind kind = core_type(x.type)->Basic.kind;
+		switch (kind) {
+		case Basic_f32:          operand->type = t_quaternion128;      break;
+		case Basic_f64:          operand->type = t_quaternion256;      break;
+		case Basic_UntypedFloat: operand->type = t_untyped_quaternion; break;
+		default: GB_PANIC("Invalid type"); break;
+		}
+
+		if (type_hint != nullptr && check_is_castable_to(c, operand, type_hint)) {
+			operand->type = type_hint;
+		}
+
 		break;
 	}
 
 	case BuiltinProc_real:
 	case BuiltinProc_imag: {
 		// real :: proc(x: type) -> float_type
-		// proc imag(x: type) -> float_type
+		// imag :: proc(x: type) -> float_type
 
 		Operand *x = operand;
 		if (is_type_untyped(x->type)) {
@@ -3719,7 +4059,12 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 				if (is_type_numeric(x->type)) {
 					x->type = t_untyped_complex;
 				}
-			} else {
+			} else if (is_type_quaternion(x->type)) {
+				convert_to_typed(c, x, t_quaternion256);
+				if (x->mode == Addressing_Invalid) {
+					return false;
+				}
+			} else{
 				convert_to_typed(c, x, t_complex128);
 				if (x->mode == Addressing_Invalid) {
 					return false;
@@ -3727,9 +4072,9 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			}
 		}
 
-		if (!is_type_complex(x->type)) {
+		if (!is_type_complex(x->type) && !is_type_quaternion(x->type)) {
 			gbString s = type_to_string(x->type);
-			error(call, "Argument has type '%s', expected a complex type", s);
+			error(call, "Argument has type '%s', expected a complex or quaternion type", s);
 			gb_string_free(s);
 			return false;
 		}
@@ -3747,10 +4092,68 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		switch (kind) {
 		case Basic_complex64:         x->type = t_f32;           break;
 		case Basic_complex128:        x->type = t_f64;           break;
+		case Basic_quaternion128:     x->type = t_f32;           break;
+		case Basic_quaternion256:     x->type = t_f64;           break;
+		case Basic_UntypedComplex:    x->type = t_untyped_float; break;
+		case Basic_UntypedQuaternion: x->type = t_untyped_float; break;
+		default: GB_PANIC("Invalid type"); break;
+		}
+
+		if (type_hint != nullptr && check_is_castable_to(c, operand, type_hint)) {
+			operand->type = type_hint;
+		}
+
+		break;
+	}
+
+	case BuiltinProc_jmag:
+	case BuiltinProc_kmag: {
+		// jmag :: proc(x: type) -> float_type
+		// kmag :: proc(x: type) -> float_type
+
+		Operand *x = operand;
+		if (is_type_untyped(x->type)) {
+			if (x->mode == Addressing_Constant) {
+				if (is_type_numeric(x->type)) {
+					x->type = t_untyped_complex;
+				}
+			} else{
+				convert_to_typed(c, x, t_quaternion256);
+				if (x->mode == Addressing_Invalid) {
+					return false;
+				}
+			}
+		}
+
+		if (!is_type_quaternion(x->type)) {
+			gbString s = type_to_string(x->type);
+			error(call, "Argument has type '%s', expected a quaternion type", s);
+			gb_string_free(s);
+			return false;
+		}
+
+		if (x->mode == Addressing_Constant) {
+			switch (id) {
+			case BuiltinProc_jmag: x->value = exact_value_jmag(x->value); break;
+			case BuiltinProc_kmag: x->value = exact_value_kmag(x->value); break;
+			}
+		} else {
+			x->mode = Addressing_Value;
+		}
+
+		BasicKind kind = core_type(x->type)->Basic.kind;
+		switch (kind) {
+		case Basic_quaternion128:     x->type = t_f32;           break;
+		case Basic_quaternion256:     x->type = t_f64;           break;
 		case Basic_UntypedComplex:    x->type = t_untyped_float; break;
+		case Basic_UntypedQuaternion: x->type = t_untyped_float; break;
 		default: GB_PANIC("Invalid type"); break;
 		}
 
+		if (type_hint != nullptr && check_is_castable_to(c, operand, type_hint)) {
+			operand->type = type_hint;
+		}
+
 		break;
 	}
 
@@ -3761,12 +4164,24 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			if (x->mode == Addressing_Constant) {
 				ExactValue v = exact_value_to_complex(x->value);
 				f64 r = v.value_complex.real;
-				f64 i = v.value_complex.imag;
+				f64 i = -v.value_complex.imag;
 				x->value = exact_value_complex(r, i);
 				x->mode = Addressing_Constant;
 			} else {
 				x->mode = Addressing_Value;
 			}
+		} else if (is_type_quaternion(x->type)) {
+			if (x->mode == Addressing_Constant) {
+				ExactValue v = exact_value_to_quaternion(x->value);
+				f64 r = v.value_quaternion.real;
+				f64 i = -v.value_quaternion.imag;
+				f64 j = -v.value_quaternion.jmag;
+				f64 k = -v.value_quaternion.kmag;
+				x->value = exact_value_quaternion(r, i, j, k);
+				x->mode = Addressing_Constant;
+			} else {
+				x->mode = Addressing_Value;
+			}
 		} else {
 			gbString s = type_to_string(x->type);
 			error(call, "Expected a complex or quaternion, got '%s'", s);
@@ -3959,6 +4374,8 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 				Type *bt = base_type(operands[0].type);
 				if (are_types_identical(bt, t_f32)) add_package_dependency(c, "runtime", "min_f32");
 				if (are_types_identical(bt, t_f64)) add_package_dependency(c, "runtime", "min_f64");
+
+				operand->type = operands[0].type;
 			}
 		}
 		break;
@@ -4119,6 +4536,8 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 				Type *bt = base_type(operands[0].type);
 				if (are_types_identical(bt, t_f32)) add_package_dependency(c, "runtime", "max_f32");
 				if (are_types_identical(bt, t_f64)) add_package_dependency(c, "runtime", "max_f64");
+
+				operand->type = operands[0].type;
 			}
 		}
 		break;
@@ -4161,6 +4580,8 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 				if (are_types_identical(bt, t_f64))        add_package_dependency(c, "runtime", "abs_f64");
 				if (are_types_identical(bt, t_complex64))  add_package_dependency(c, "runtime", "abs_complex64");
 				if (are_types_identical(bt, t_complex128)) add_package_dependency(c, "runtime", "abs_complex128");
+				if (are_types_identical(bt, t_quaternion128)) add_package_dependency(c, "runtime", "abs_quaternion128");
+				if (are_types_identical(bt, t_quaternion256)) add_package_dependency(c, "runtime", "abs_quaternion256");
 			}
 		}
 
@@ -4266,6 +4687,8 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 					add_package_dependency(c, "runtime", "min_f64");
 					add_package_dependency(c, "runtime", "max_f64");
 				}
+
+				operand->type = ops[0]->type;
 			}
 		}
 
@@ -4439,6 +4862,123 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			break;
 		}
 		break;
+
+	case BuiltinProc_type_base_type:
+		if (operand->mode != Addressing_Type) {
+			error(operand->expr, "Expected a type for '%.*s'", LIT(builtin_name));
+		} else {
+			operand->type = base_type(operand->type);
+		}
+		operand->mode = Addressing_Type;
+		break;
+	case BuiltinProc_type_core_type:
+		if (operand->mode != Addressing_Type) {
+			error(operand->expr, "Expected a type for '%.*s'", LIT(builtin_name));
+		} else {
+			operand->type = core_type(operand->type);
+		}
+		operand->mode = Addressing_Type;
+		break;
+	case BuiltinProc_type_elem_type:
+		if (operand->mode != Addressing_Type) {
+			error(operand->expr, "Expected a type for '%.*s'", LIT(builtin_name));
+		} else {
+			Type *bt = base_type(operand->type);
+			switch (bt->kind) {
+			case Type_Basic:
+				switch (bt->Basic.kind) {
+				case Basic_complex64:  operand->type = t_f32; break;
+				case Basic_complex128: operand->type = t_f64; break;
+				}
+				break;
+			case Type_Pointer:      operand->type = bt->Pointer.elem;      break;
+			case Type_Opaque:       operand->type = bt->Opaque.elem;       break;
+			case Type_Array:        operand->type = bt->Array.elem;        break;
+			case Type_Slice:        operand->type = bt->Slice.elem;        break;
+			case Type_DynamicArray: operand->type = bt->DynamicArray.elem; break;
+			}
+		}
+		operand->mode = Addressing_Type;
+		break;
+
+
+	case BuiltinProc_type_is_boolean:
+	case BuiltinProc_type_is_integer:
+	case BuiltinProc_type_is_rune:
+	case BuiltinProc_type_is_float:
+	case BuiltinProc_type_is_complex:
+	case BuiltinProc_type_is_quaternion:
+	case BuiltinProc_type_is_string:
+	case BuiltinProc_type_is_typeid:
+	case BuiltinProc_type_is_any:
+	case BuiltinProc_type_is_endian_little:
+	case BuiltinProc_type_is_endian_big:
+	case BuiltinProc_type_is_numeric:
+	case BuiltinProc_type_is_ordered:
+	case BuiltinProc_type_is_ordered_numeric:
+	case BuiltinProc_type_is_indexable:
+	case BuiltinProc_type_is_sliceable:
+	case BuiltinProc_type_is_simple_compare:
+	case BuiltinProc_type_is_dereferenceable:
+	case BuiltinProc_type_is_valid_map_key:
+	case BuiltinProc_type_is_named:
+	case BuiltinProc_type_is_pointer:
+	case BuiltinProc_type_is_opaque:
+	case BuiltinProc_type_is_array:
+	case BuiltinProc_type_is_slice:
+	case BuiltinProc_type_is_dynamic_array:
+	case BuiltinProc_type_is_map:
+	case BuiltinProc_type_is_struct:
+	case BuiltinProc_type_is_union:
+	case BuiltinProc_type_is_enum:
+	case BuiltinProc_type_is_proc:
+	case BuiltinProc_type_is_bit_field:
+	case BuiltinProc_type_is_bit_field_value:
+	case BuiltinProc_type_is_bit_set:
+	case BuiltinProc_type_is_simd_vector:
+	case BuiltinProc_type_has_nil:
+		GB_ASSERT(BuiltinProc__type_begin < id && id < BuiltinProc__type_end);
+		operand->value = exact_value_bool(false);
+		if (operand->mode != Addressing_Type) {
+			gbString str = expr_to_string(ce->args[0]);
+			error(operand->expr, "Expected a type for '%.*s', got '%s'", LIT(builtin_name), str);
+			gb_string_free(str);
+		} else {
+			i32 i = id - (BuiltinProc__type_begin+1);
+			auto procedure = builtin_type_is_procs[i];
+			GB_ASSERT_MSG(procedure != nullptr, "%.*s", LIT(builtin_name));
+			operand->value = exact_value_bool(procedure(operand->type));
+		}
+		operand->mode = Addressing_Constant;
+		operand->type = t_untyped_bool;
+		break;
+
+	case BuiltinProc_type_proc_parameter_count:
+		operand->value = exact_value_i64(0);
+		if (operand->mode != Addressing_Type) {
+			error(operand->expr, "Expected a procedure type for '%.*s'", LIT(builtin_name));
+		} else if (!is_type_proc(operand->type)) {
+			error(operand->expr, "Expected a procedure type for '%.*s'", LIT(builtin_name));
+		} else {
+			Type *bt = base_type(operand->type);
+			operand->value = exact_value_i64(bt->Proc.param_count);
+		}
+		operand->mode = Addressing_Constant;
+		operand->type = t_untyped_integer;
+		break;
+	case BuiltinProc_type_proc_return_count:
+		operand->value = exact_value_i64(0);
+		if (operand->mode != Addressing_Type) {
+			error(operand->expr, "Expected a procedure type for '%.*s'", LIT(builtin_name));
+		} else if (!is_type_proc(operand->type)) {
+			error(operand->expr, "Expected a procedure type for '%.*s'", LIT(builtin_name));
+		} else {
+			Type *bt = base_type(operand->type);
+			operand->value = exact_value_i64(bt->Proc.result_count);
+		}
+		operand->mode = Addressing_Constant;
+		operand->type = t_untyped_integer;
+		break;
 	}
 
 	return true;
@@ -4455,7 +4995,7 @@ isize add_dependencies_from_unpacking(CheckerContext *c, Entity **lhs, isize lhs
 					c->decl = decl; // will be reset by the 'defer' any way
 					for_array(k, decl->deps.entries) {
 						Entity *dep = decl->deps.entries[k].ptr;
-						add_declaration_dependency(c, dep); // TODO(bill): Should this be here?
+     						add_declaration_dependency(c, dep); // TODO(bill): Should this be here?
 					}
 				}
 			}
@@ -4774,6 +5314,11 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 					}
 				}
 				score += s;
+
+				if (o.mode == Addressing_Type && is_type_typeid(e->type)) {
+					add_type_info_type(c, o.type);
+					add_type_and_value(c->info, o.expr, Addressing_Value, e->type, exact_value_typeid(o.type));
+				}
 			}
 
 			if (variadic) {
@@ -4816,6 +5361,10 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 					if (is_type_any(elem)) {
 						add_type_info_type(c, o.type);
 					}
+					if (o.mode == Addressing_Type && is_type_typeid(t)) {
+						add_type_info_type(c, o.type);
+						add_type_and_value(c->info, o.expr, Addressing_Value, t, exact_value_typeid(o.type));
+					}
 				}
 			}
 		}
@@ -5016,6 +5565,11 @@ CALL_ARGUMENT_CHECKER(check_named_call_arguments) {
 			}
 			score += s;
 		}
+
+		if (o->mode == Addressing_Type && is_type_typeid(e->type)) {
+			add_type_info_type(c, o->type);
+			add_type_and_value(c->info, o->expr, Addressing_Value, e->type, exact_value_typeid(o->type));
+		}
 	}
 
 	if (data) {
@@ -5061,6 +5615,69 @@ Entity **populate_proc_parameter_list(CheckerContext *c, Type *proc_type, isize
 	return lhs;
 }
 
+
+bool evaluate_where_clauses(CheckerContext *ctx, Scope *scope, Array<Ast *> *clauses, bool print_err) {
+	if (clauses != nullptr) {
+		for_array(i, *clauses) {
+			Ast *clause = (*clauses)[i];
+			Operand o = {};
+			check_expr(ctx, &o, clause);
+			if (o.mode != Addressing_Constant) {
+				if (print_err) error(clause, "'where' clauses expect a constant boolean evaluation");
+				return false;
+			} else if (o.value.kind != ExactValue_Bool) {
+				if (print_err) error(clause, "'where' clauses expect a constant boolean evaluation");
+				return false;
+			} else if (!o.value.value_bool) {
+				if (print_err) {
+					gbString str = expr_to_string(clause);
+					error(clause, "'where' clause evaluated to false:\n\t%s", str);
+					gb_string_free(str);
+
+					if (scope != nullptr) {
+						isize print_count = 0;
+						for_array(j, scope->elements.entries) {
+							Entity *e = scope->elements.entries[j].value;
+							switch (e->kind) {
+							case Entity_TypeName: {
+								if (print_count == 0) error_line("\n\tWith the following definitions:\n");
+
+								gbString str = type_to_string(e->type);
+								error_line("\t\t%.*s :: %s;\n", LIT(e->token.string), str);
+								gb_string_free(str);
+								print_count += 1;
+								break;
+							}
+							case Entity_Constant: {
+								if (print_count == 0) error_line("\n\tWith the following definitions:\n");
+
+								gbString str = exact_value_to_string(e->Constant.value);
+								if (is_type_untyped(e->type)) {
+									error_line("\t\t%.*s :: %s;\n", LIT(e->token.string), str);
+								} else {
+									gbString t = type_to_string(e->type);
+									error_line("\t\t%.*s : %s : %s;\n", LIT(e->token.string), t, str);
+									gb_string_free(t);
+								}
+								gb_string_free(str);
+
+								print_count += 1;
+								break;
+							}
+							}
+						}
+					}
+
+				}
+				return false;
+			}
+		}
+	}
+
+	return true;
+}
+
+
 CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type *proc_type, Ast *call) {
 	ast_node(ce, CallExpr, call);
 
@@ -5238,6 +5855,7 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 			}
 
 
+
 			if (proc_arg_count >= 0 && proc_arg_count_all_equal) {
 				lhs_count = proc_arg_count;
 				if (lhs_count > 0)  {
@@ -5281,9 +5899,8 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 			gb_free(heap_allocator(), lhs);
 		}
 
-		ValidIndexAndScore *valids         = gb_alloc_array(heap_allocator(), ValidIndexAndScore, procs.count);
-		isize               valid_count    = 0;
-		defer (gb_free(heap_allocator(), valids));
+		auto valids = array_make<ValidIndexAndScore>(heap_allocator(), 0, procs.count);
+		defer (array_free(&valids));
 
 		gbString expr_name = expr_to_string(operand->expr);
 		defer (gb_string_free(expr_name));
@@ -5298,36 +5915,54 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 
 				ctx.no_polymorphic_errors = true;
 				ctx.allow_polymorphic_types = is_type_polymorphic(pt);
+				ctx.hide_polymorphic_errors = true;
 
 				err = call_checker(&ctx, call, pt, p, operands, CallArgumentMode_NoErrors, &data);
 
-				if (err == CallArgumentError_None) {
-					valids[valid_count].index = i;
-					valids[valid_count].score = data.score;
-					valid_count++;
+				if (err != CallArgumentError_None) {
+					continue;
+				}
+
+				if (data.gen_entity != nullptr) {
+					Entity *e = data.gen_entity;
+					DeclInfo *decl = data.gen_entity->decl_info;
+					ctx.scope = decl->scope;
+					ctx.decl = decl;
+					ctx.proc_name = e->token.string;
+					ctx.curr_proc_decl = decl;
+					ctx.curr_proc_sig  = e->type;
+
+					GB_ASSERT(decl->proc_lit->kind == Ast_ProcLit);
+					if (!evaluate_where_clauses(&ctx, decl->scope, &decl->proc_lit->ProcLit.where_clauses, false)) {
+						continue;
+					}
 				}
+
+				ValidIndexAndScore item = {};
+				item.index = i;
+				item.score = data.score;
+				array_add(&valids, item);
 			}
 		}
 
-		if (valid_count > 1) {
-			gb_sort_array(valids, valid_count, valid_index_and_score_cmp);
+		if (valids.count > 1) {
+			gb_sort_array(valids.data, valids.count, valid_index_and_score_cmp);
 			i64 best_score = valids[0].score;
 			Entity *best_entity = procs[valids[0].index];
-			for (isize i = 1; i < valid_count; i++) {
+			for (isize i = 1; i < valids.count; i++) {
 				if (best_score > valids[i].score) {
-					valid_count = i;
+					valids.count = i;
 					break;
 				}
 				if (best_entity == procs[valids[i].index]) {
-					valid_count = i;
+					valids.count = i;
 					break;
 				}
-				best_score = valids[i].score;
 			}
 		}
 
 
-		if (valid_count == 0) {
+		if (valids.count == 0) {
 			begin_error_block();
 			defer (end_error_block());
 
@@ -5382,7 +6017,7 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 			}
 
 			result_type = t_invalid;
-		} else if (valid_count > 1) {
+		} else if (valids.count > 1) {
 			begin_error_block();
 			defer (end_error_block());
 
@@ -5397,11 +6032,11 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 			}
 			error_line(")\n");
 
-			for (isize i = 0; i < valid_count; i++) {
+			for (isize i = 0; i < valids.count; i++) {
 				Entity *proc = procs[valids[i].index];
 				TokenPos pos = proc->token.pos;
 				Type *t = base_type(proc->type); GB_ASSERT(t->kind == Type_Proc);
-				gbString pt;
+				gbString pt = nullptr;
 				defer (gb_string_free(pt));
 				if (t->Proc.node != nullptr) {
 					pt = expr_to_string(t->Proc.node);
@@ -5413,7 +6048,29 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 				if (proc->kind == Entity_Variable) {
 					sep = ":=";
 				}
-				error_line("\t%.*s %s %s at %.*s(%td:%td)\n", LIT(name), sep, pt, LIT(pos.file), pos.line, pos.column);
+				error_line("\t%.*s %s %s ", LIT(name), sep, pt);
+				if (proc->decl_info->proc_lit != nullptr) {
+					GB_ASSERT(proc->decl_info->proc_lit->kind == Ast_ProcLit);
+					auto *pl = &proc->decl_info->proc_lit->ProcLit;
+					if (pl->where_token.kind != Token_Invalid) {
+						error_line("\n\t\twhere ");
+						for_array(j, pl->where_clauses) {
+							Ast *clause = pl->where_clauses[j];
+							if (j != 0) {
+								error_line("\t\t      ");
+							}
+							gbString str = expr_to_string(clause);
+							error_line("%s", str);
+							gb_string_free(str);
+
+							if (j != pl->where_clauses.count-1) {
+								error_line(",");
+							}
+						}
+						error_line("\n\t");
+					}
+				}
+				error_line("at %.*s(%td:%td)\n", LIT(pos.file), pos.line, pos.column);
 				// error_line("\t%.*s %s %s at %.*s(%td:%td) %lld\n", LIT(name), sep, pt, LIT(pos.file), pos.line, pos.column, valids[i].score);
 			}
 			result_type = t_invalid;
@@ -5492,24 +6149,57 @@ CallArgumentError check_polymorphic_record_type(CheckerContext *c, Operand *oper
 	defer (array_free(&operands));
 
 	bool named_fields = false;
+	{
+		// NOTE(bill, 2019-10-26): Allow a cycle in the parameters but not in the fields themselves
+		auto prev_type_path = c->type_path;
+		c->type_path = new_checker_type_path();
+		defer ({
+			destroy_checker_type_path(c->type_path);
+			c->type_path = prev_type_path;
+		});
+
+		if (is_call_expr_field_value(ce)) {
+			named_fields = true;
+			operands = array_make<Operand>(heap_allocator(), ce->args.count);
+			for_array(i, ce->args) {
+				Ast *arg = ce->args[i];
+				ast_node(fv, FieldValue, arg);
+
+				if (fv->field->kind == Ast_Ident) {
+					String name = fv->field->Ident.token.string;
+					isize index = lookup_polymorphic_record_parameter(original_type, name);
+					if (index >= 0) {
+						TypeTuple *params = get_record_polymorphic_params(original_type);
+						Entity *e = params->variables[i];
+						if (e->kind == Entity_Constant) {
+							check_expr_with_type_hint(c, &operands[i], fv->value, e->type);
+						}
+					}
 
-	if (is_call_expr_field_value(ce)) {
-		named_fields = true;
-		operands = array_make<Operand>(heap_allocator(), ce->args.count);
-		for_array(i, ce->args) {
-			Ast *arg = ce->args[i];
-			ast_node(fv, FieldValue, arg);
-			check_expr_or_type(c, &operands[i], fv->value);
-		}
+				}
+				check_expr_or_type(c, &operands[i], fv->value);
+			}
+
+			bool vari_expand = (ce->ellipsis.pos.line != 0);
+			if (vari_expand) {
+				error(ce->ellipsis, "Invalid use of '..' in a polymorphic type call'");
+			}
 
-		bool vari_expand = (ce->ellipsis.pos.line != 0);
-		if (vari_expand) {
-			error(ce->ellipsis, "Invalid use of '..' in a polymorphic type call'");
+		} else {
+			operands = array_make<Operand>(heap_allocator(), 0, 2*ce->args.count);
+
+			Entity **lhs = nullptr;
+			isize lhs_count = -1;
+
+			TypeTuple *params = get_record_polymorphic_params(original_type);
+			if (params != nullptr) {
+				lhs = params->variables.data;
+				lhs_count = params->variables.count;
+			}
+
+			check_unpack_arguments(c, lhs, lhs_count, &operands, ce->args, false, false);
 		}
 
-	} else {
-		operands = array_make<Operand>(heap_allocator(), 0, 2*ce->args.count);
-		check_unpack_arguments(c, nullptr, -1, &operands, ce->args, false, false);
 	}
 
 	CallArgumentError err = CallArgumentError_None;
@@ -5638,12 +6328,16 @@ CallArgumentError check_polymorphic_record_type(CheckerContext *c, Operand *oper
 			}
 			score += s;
 		}
+
+		// NOTE(bill): Add type info the parameters
+		add_type_info_type(c, o->type);
 	}
 
 	{
 		gbAllocator a = c->allocator;
 
-		Entity *found_entity = find_polymorphic_record_entity(c, original_type, param_count, ordered_operands);
+		bool failure = false;
+		Entity *found_entity = find_polymorphic_record_entity(c, original_type, param_count, ordered_operands, &failure);
 		if (found_entity) {
 			operand->mode = Addressing_Type;
 			operand->type = found_entity->type;
@@ -5692,13 +6386,13 @@ CallArgumentError check_polymorphic_record_type(CheckerContext *c, Operand *oper
 
 
 
-ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call) {
+ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call, Type *type_hint) {
 	ast_node(ce, CallExpr, call);
 	if (ce->proc != nullptr &&
 	    ce->proc->kind == Ast_BasicDirective) {
 		ast_node(bd, BasicDirective, ce->proc);
 		String name = bd->name;
-		if (name == "location" || name == "assert" || name == "defined" || name == "load") {
+		if (name == "location" || name == "assert" || name == "panic" || name == "defined" || name == "load") {
 			operand->mode = Addressing_Builtin;
 			operand->builtin_id = BuiltinProc_DIRECTIVE;
 			operand->expr = ce->proc;
@@ -5761,7 +6455,8 @@ ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call) {
 					Ast *s = ident->SelectorExpr.selector;
 					ident = s;
 				}
-				Type *ot = operand->type; GB_ASSERT(ot->kind == Type_Named);
+				Type *ot = operand->type;
+				GB_ASSERT(ot->kind == Type_Named);
 				Entity *e = ot->Named.type_name;
 				add_entity_use(c, ident, e);
 				add_type_and_value(&c->checker->info, call, Addressing_Type, ot, empty_exact_value);
@@ -5799,7 +6494,7 @@ ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call) {
 
 	if (operand->mode == Addressing_Builtin) {
 		i32 id = operand->builtin_id;
-		if (!check_builtin_procedure(c, operand, call, id)) {
+		if (!check_builtin_procedure(c, operand, call, id, type_hint)) {
 			operand->mode = Addressing_Invalid;
 		}
 		operand->expr = call;
@@ -5825,17 +6520,6 @@ ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call) {
 		}
 	}
 
-	// NOTE(bill): Should this be here or on the `add_entity_use`?
-	// if (ce->proc != nullptr) {
-	// 	Entity *e = entity_of_node(&c->info, ce->proc);
-	// 	if (e != nullptr && e->kind == Entity_Procedure) {
-	// 		String msg = e->Procedure.deprecated_message;
-	// 		if (msg.len > 0) {
-	// 			warning(call, "%.*s is deprecated: %.*s", LIT(e->token.string), LIT(msg));
-	// 		}
-	// 	}
-	// }
-
 	CallArgumentData data = check_call_arguments(c, operand, proc_type, call);
 	Type *result_type = data.result_type;
 	gb_zero_item(operand);
@@ -5975,6 +6659,98 @@ bool ternary_compare_types(Type *x, Type *y) {
 }
 
 
+bool check_range(CheckerContext *c, Ast *node, Operand *x, Operand *y, ExactValue *inline_for_depth_) {
+	if (!is_ast_range(node)) {
+		return false;
+	}
+
+	ast_node(ie, BinaryExpr, node);
+
+	check_expr(c, x, ie->left);
+	if (x->mode == Addressing_Invalid) {
+		return false;
+	}
+	check_expr(c, y, ie->right);
+	if (y->mode == Addressing_Invalid) {
+		return false;
+	}
+
+	convert_to_typed(c, x, y->type);
+	if (x->mode == Addressing_Invalid) {
+		return false;
+	}
+	convert_to_typed(c, y, x->type);
+	if (y->mode == Addressing_Invalid) {
+		return false;
+	}
+
+	convert_to_typed(c, x, default_type(y->type));
+	if (x->mode == Addressing_Invalid) {
+		return false;
+	}
+	convert_to_typed(c, y, default_type(x->type));
+	if (y->mode == Addressing_Invalid) {
+		return false;
+	}
+
+	if (!are_types_identical(x->type, y->type)) {
+		if (x->type != t_invalid &&
+		    y->type != t_invalid) {
+			gbString xt = type_to_string(x->type);
+			gbString yt = type_to_string(y->type);
+			gbString expr_str = expr_to_string(x->expr);
+			error(ie->op, "Mismatched types in interval expression '%s' : '%s' vs '%s'", expr_str, xt, yt);
+			gb_string_free(expr_str);
+			gb_string_free(yt);
+			gb_string_free(xt);
+		}
+		return false;
+	}
+
+	Type *type = x->type;
+	if (!is_type_integer(type) && !is_type_float(type) && !is_type_pointer(type) && !is_type_enum(type)) {
+		error(ie->op, "Only numerical and pointer types are allowed within interval expressions");
+		return false;
+	}
+
+	if (x->mode == Addressing_Constant &&
+	    y->mode == Addressing_Constant) {
+		ExactValue a = x->value;
+		ExactValue b = y->value;
+
+		GB_ASSERT(are_types_identical(x->type, y->type));
+
+		TokenKind op = Token_Lt;
+		switch (ie->op.kind) {
+		case Token_Ellipsis:  op = Token_LtEq; break;
+		case Token_RangeHalf: op = Token_Lt; break;
+		default: error(ie->op, "Invalid range operator"); break;
+		}
+		bool ok = compare_exact_values(op, a, b);
+		if (!ok) {
+			// TODO(bill): Better error message
+			error(ie->op, "Invalid interval range");
+			return false;
+		}
+
+		ExactValue inline_for_depth = exact_value_sub(b, a);
+		if (ie->op.kind == Token_Ellipsis) {
+			inline_for_depth = exact_value_increment_one(inline_for_depth);
+		}
+
+		if (inline_for_depth_) *inline_for_depth_ = inline_for_depth;
+	} else {
+		error(ie->op, "Interval expressions must be constant");
+		return false;
+	}
+
+	add_type_and_value(&c->checker->info, ie->left,  x->mode, x->type, x->value);
+	add_type_and_value(&c->checker->info, ie->right, y->mode, y->type, y->value);
+
+	return true;
+}
+
+
 
 ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type *type_hint) {
 	ExprKind kind = Expr_Stmt;
@@ -6037,32 +6813,26 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 
 
 	case_ast_node(bl, BasicLit, node);
-		// NOTE(bill, 2018-06-17): Placing this in the parser is slower than
-		// placing it here for some reason. So don't move it to the parsing
-		// stage if you _think_ it will be faster, only do it if you _know_ it
-		// will be faster.
 		Type *t = t_invalid;
-		switch (bl->token.kind) {
-		case Token_Integer: t = t_untyped_integer; break;
-		case Token_Float:   t = t_untyped_float;   break;
-		case Token_String:  t = t_untyped_string;  break;
-		case Token_Rune:    t = t_untyped_rune;    break;
-		case Token_Imag: {
-			String s = bl->token.string;
-			Rune r = s[s.len-1];
-			switch (r) {
-			case 'i': t = t_untyped_complex; break;
+		switch (bl->value.kind) {
+		case ExactValue_String:     t = t_untyped_string;     break;
+		case ExactValue_Float:      t = t_untyped_float;      break;
+		case ExactValue_Complex:    t = t_untyped_complex;    break;
+		case ExactValue_Quaternion: t = t_untyped_quaternion; break;
+		case ExactValue_Integer:
+			t = t_untyped_integer;
+			if (bl->token.kind == Token_Rune) {
+				t = t_untyped_rune;
 			}
-
 			break;
-		}
 		default:
-			GB_PANIC("Unknown literal");
+			GB_PANIC("Unhandled value type for basic literal");
 			break;
 		}
+
 		o->mode  = Addressing_Constant;
 		o->type  = t;
-		o->value = exact_value_from_basic_literal(bl->token);
+		o->value = bl->value;
 	case_end;
 
 	case_ast_node(bd, BasicDirective, node);
@@ -6107,6 +6877,7 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 			decl = make_decl_info(ctx.allocator, ctx.scope, ctx.decl);
 			decl->proc_lit  = node;
 			ctx.decl = decl;
+			defer (ctx.decl = ctx.decl->parent);
 
 			if (pl->tags != 0) {
 				error(node, "A procedure literal cannot have tags");
@@ -6412,7 +7183,6 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 
 
 			i64 max = 0;
-			isize index = 0;
 
 			Type *bet = base_type(elem_type);
 			if (!elem_type_can_be_constant(bet)) {
@@ -6423,40 +7193,152 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 				break;
 			}
 
-			for (; index < cl->elems.count; index++) {
-				Ast *e = cl->elems[index];
-				if (e == nullptr) {
-					error(node, "Invalid literal element");
-					continue;
-				}
+			if (cl->elems.count > 0 && cl->elems[0]->kind == Ast_FieldValue) {
+				if (is_type_simd_vector(t)) {
+					error(cl->elems[0], "'field = value' is not allowed for SIMD vector literals");
+				} else {
+					RangeCache rc = range_cache_make(heap_allocator());
+					defer (range_cache_destroy(&rc));
 
-				if (e->kind == Ast_FieldValue) {
-					error(e, "'field = value' is only allowed in struct literals");
-					continue;
-				}
+					for_array(i, cl->elems) {
+						Ast *elem = cl->elems[i];
+						if (elem->kind != Ast_FieldValue) {
+							error(elem, "Mixture of 'field = value' and value elements in a literal is not allowed");
+							continue;
+						}
+						ast_node(fv, FieldValue, elem);
+
+						if (is_ast_range(fv->field)) {
+							Token op = fv->field->BinaryExpr.op;
+
+							Operand x = {};
+							Operand y = {};
+							bool ok = check_range(c, fv->field, &x, &y, nullptr);
+							if (!ok) {
+								continue;
+							}
+							if (x.mode != Addressing_Constant || !is_type_integer(core_type(x.type))) {
+								error(x.expr, "Expected a constant integer as an array field");
+								continue;
+							}
+
+							if (y.mode != Addressing_Constant || !is_type_integer(core_type(y.type))) {
+								error(y.expr, "Expected a constant integer as an array field");
+								continue;
+							}
+
+							i64 lo = exact_value_to_i64(x.value);
+							i64 hi = exact_value_to_i64(y.value);
+							i64 max_index = hi;
+							if (op.kind == Token_RangeHalf) {
+								hi -= 1;
+							}
+
+							bool new_range = range_cache_add_range(&rc, lo, hi);
+							if (!new_range) {
+								error(elem, "Overlapping field range index %lld %.*s %lld for %.*s", lo, LIT(op.string), hi, LIT(context_name));
+								continue;
+							}
+
+
+							if (max_type_count >= 0 && (lo < 0 || lo >= max_type_count)) {
+								error(elem, "Index %lld is out of bounds (0..<%lld) for %.*s", lo, max_type_count, LIT(context_name));
+								continue;
+							}
+							if (max_type_count >= 0 && (hi < 0 || hi >= max_type_count)) {
+								error(elem, "Index %lld is out of bounds (0..<%lld) for %.*s", hi, max_type_count, LIT(context_name));
+								continue;
+							}
+
+							if (max < hi) {
+								max = max_index;
+							}
+
+							Operand operand = {};
+							check_expr_with_type_hint(c, &operand, fv->value, elem_type);
+							check_assignment(c, &operand, elem_type, context_name);
+
+							is_constant = is_constant && operand.mode == Addressing_Constant;
+						} else {
+							Operand op_index = {};
+							check_expr(c, &op_index, fv->field);
+
+							if (op_index.mode != Addressing_Constant || !is_type_integer(core_type(op_index.type))) {
+								error(elem, "Expected a constant integer as an array field");
+								continue;
+							}
 
-				if (0 <= max_type_count && max_type_count <= index) {
-					error(e, "Index %lld is out of bounds (>= %lld) for %.*s", index, max_type_count, LIT(context_name));
+							i64 index = exact_value_to_i64(op_index.value);
+
+							if (max_type_count >= 0 && (index < 0 || index >= max_type_count)) {
+								error(elem, "Index %lld is out of bounds (0..<%lld) for %.*s", index, max_type_count, LIT(context_name));
+								continue;
+							}
+
+							bool new_index = range_cache_add_index(&rc, index);
+							if (!new_index) {
+								error(elem, "Duplicate field index %lld for %.*s", index, LIT(context_name));
+								continue;
+							}
+
+							if (max < index+1) {
+								max = index+1;
+							}
+
+							Operand operand = {};
+							check_expr_with_type_hint(c, &operand, fv->value, elem_type);
+							check_assignment(c, &operand, elem_type, context_name);
+
+							is_constant = is_constant && operand.mode == Addressing_Constant;
+						}
+					}
+
+					cl->max_count = max;
 				}
 
-				Operand operand = {};
-				check_expr_with_type_hint(c, &operand, e, elem_type);
-				check_assignment(c, &operand, elem_type, context_name);
 
-				is_constant = is_constant && operand.mode == Addressing_Constant;
-			}
-			if (max < index) {
-				max = index;
+			} else {
+				isize index = 0;
+				for (; index < cl->elems.count; index++) {
+					Ast *e = cl->elems[index];
+					if (e == nullptr) {
+						error(node, "Invalid literal element");
+						continue;
+					}
+
+					if (e->kind == Ast_FieldValue) {
+						error(e, "Mixture of 'field = value' and value elements in a literal is not allowed");
+						continue;
+					}
+
+					if (0 <= max_type_count && max_type_count <= index) {
+						error(e, "Index %lld is out of bounds (>= %lld) for %.*s", index, max_type_count, LIT(context_name));
+					}
+
+					Operand operand = {};
+					check_expr_with_type_hint(c, &operand, e, elem_type);
+					check_assignment(c, &operand, elem_type, context_name);
+
+					is_constant = is_constant && operand.mode == Addressing_Constant;
+				}
+
+				if (max < index) {
+					max = index;
+				}
 			}
 
+
 			if (t->kind == Type_Array) {
 				if (is_to_be_determined_array_count) {
 					t->Array.count = max;
-				} else if (0 < max && max < t->Array.count) {
-					error(node, "Expected %lld values for this array literal, got %lld", cast(long long)t->Array.count, cast(long long)max);
+				} else if (cl->elems.count > 0 && cl->elems[0]->kind != Ast_FieldValue) {
+					if (0 < max && max < t->Array.count) {
+						error(node, "Expected %lld values for this array literal, got %lld", cast(long long)t->Array.count, cast(long long)max);
+					}
 				}
 			}
 
+
 			if (t->kind == Type_SimdVector) {
 				if (!is_constant) {
 					error(node, "Expected all constant elements for a simd vector");
@@ -6828,7 +7710,7 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 
 
 	case_ast_node(be, BinaryExpr, node);
-		check_binary_expr(c, o, node, true);
+		check_binary_expr(c, o, node, type_hint, true);
 		if (o->mode == Addressing_Invalid) {
 			o->expr = node;
 			return kind;
@@ -6992,7 +7874,7 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 				if (o->mode == Addressing_Constant) {
 					max_count = o->value.value_string.len;
 				}
-				o->type = t_string;
+				o->type = type_deref(o->type);
 			}
 			break;
 
@@ -7072,7 +7954,7 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 
 
 	case_ast_node(ce, CallExpr, node);
-		return check_call_expr(c, o, node);
+		return check_call_expr(c, o, node, type_hint);
 	case_end;
 
 	case_ast_node(de, DerefExpr, node);
@@ -7111,6 +7993,9 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 	case Ast_UnionType:
 	case Ast_EnumType:
 	case Ast_MapType:
+	case Ast_OpaqueType:
+	case Ast_BitSetType:
+	case Ast_BitFieldType:
 		o->mode = Addressing_Type;
 		o->type = check_type(c, node);
 		break;
diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index e2090688f..d4398664b 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -132,6 +132,10 @@ bool check_is_terminating(Ast *node) {
 		}
 	case_end;
 
+	case_ast_node(rs, InlineRangeStmt, node);
+		return false;
+	case_end;
+
 	case_ast_node(rs, RangeStmt, node);
 		return false;
 	case_end;
@@ -492,8 +496,7 @@ bool check_using_stmt_entity(CheckerContext *ctx, AstUsingStmt *us, Ast *expr, b
 			for_array(i, found->elements.entries) {
 				Entity *f = found->elements.entries[i].value;
 				if (f->kind == Entity_Variable) {
-					Entity *uvar = alloc_entity_using_variable(e, f->token, f->type);
-					uvar->using_expr = expr;
+					Entity *uvar = alloc_entity_using_variable(e, f->token, f->type, expr);
 					Entity *prev = scope_insert(ctx->scope, uvar);
 					if (prev != nullptr) {
 						gbString expr_str = expr_to_string(expr);
@@ -587,6 +590,162 @@ void add_constant_switch_case(CheckerContext *ctx, Map<TypeAndToken> *seen, Oper
 	multi_map_insert(seen, key, tap);
 }
 
+void check_inline_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
+	ast_node(irs, InlineRangeStmt, node);
+	check_open_scope(ctx, node);
+
+	Type *val0 = nullptr;
+	Type *val1 = nullptr;
+	Entity *entities[2] = {};
+	isize entity_count = 0;
+
+	Ast *expr = unparen_expr(irs->expr);
+
+	ExactValue inline_for_depth = exact_value_i64(0);
+
+	if (is_ast_range(expr)) {
+		ast_node(ie, BinaryExpr, expr);
+		Operand x = {};
+		Operand y = {};
+
+		bool ok = check_range(ctx, expr, &x, &y, &inline_for_depth);
+		if (!ok) {
+			goto skip_expr;
+		}
+
+		val0 = x.type;
+		val1 = t_int;
+	} else {
+		Operand operand = {Addressing_Invalid};
+		check_expr_or_type(ctx, &operand, irs->expr);
+
+		if (operand.mode == Addressing_Type) {
+			if (!is_type_enum(operand.type)) {
+				gbString t = type_to_string(operand.type);
+				error(operand.expr, "Cannot iterate over the type '%s'", t);
+				gb_string_free(t);
+				goto skip_expr;
+			} else {
+				val0 = operand.type;
+				val1 = t_int;
+				add_type_info_type(ctx, operand.type);
+
+				Type *bt = base_type(operand.type);
+				inline_for_depth = exact_value_i64(bt->Enum.fields.count);
+				goto skip_expr;
+			}
+		} else if (operand.mode != Addressing_Invalid) {
+			Type *t = base_type(operand.type);
+			switch (t->kind) {
+			case Type_Basic:
+				if (is_type_string(t) && t->Basic.kind != Basic_cstring) {
+					val0 = t_rune;
+					val1 = t_int;
+					inline_for_depth = exact_value_i64(operand.value.value_string.len);
+				}
+				break;
+			case Type_Array:
+				val0 = t->Array.elem;
+				val1 = t_int;
+				inline_for_depth = exact_value_i64(t->Array.count);
+				break;
+			}
+		}
+
+		if (val0 == nullptr) {
+			gbString s = expr_to_string(operand.expr);
+			gbString t = type_to_string(operand.type);
+			error(operand.expr, "Cannot iterate over '%s' of type '%s' in an 'inline for' statement", s, t);
+			gb_string_free(t);
+			gb_string_free(s);
+		} else if (operand.mode != Addressing_Constant) {
+			error(operand.expr, "An 'inline for' expression must be known at compile time");
+		}
+	}
+
+	skip_expr:; // NOTE(zhiayang): again, declaring a variable immediately after a label... weird.
+
+	Ast * lhs[2] = {irs->val0, irs->val1};
+	Type *rhs[2] = {val0, val1};
+
+	for (isize i = 0; i < 2; i++) {
+		if (lhs[i] == nullptr) {
+			continue;
+		}
+		Ast * name = lhs[i];
+		Type *type = rhs[i];
+
+		Entity *entity = nullptr;
+		if (name->kind == Ast_Ident) {
+			Token token = name->Ident.token;
+			String str = token.string;
+			Entity *found = nullptr;
+
+			if (!is_blank_ident(str)) {
+				found = scope_lookup_current(ctx->scope, str);
+			}
+			if (found == nullptr) {
+				bool is_immutable = true;
+				entity = alloc_entity_variable(ctx->scope, token, type, is_immutable, EntityState_Resolved);
+				entity->flags |= EntityFlag_Value;
+				add_entity_definition(&ctx->checker->info, name, entity);
+			} else {
+				TokenPos pos = found->token.pos;
+				error(token,
+				      "Redeclaration of '%.*s' in this scope\n"
+				      "\tat %.*s(%td:%td)",
+				      LIT(str), LIT(pos.file), pos.line, pos.column);
+				entity = found;
+			}
+		} else {
+			error(name, "A variable declaration must be an identifier");
+		}
+
+		if (entity == nullptr) {
+			entity = alloc_entity_dummy_variable(builtin_pkg->scope, ast_token(name));
+		}
+
+		entities[entity_count++] = entity;
+
+		if (type == nullptr) {
+			entity->type = t_invalid;
+			entity->flags |= EntityFlag_Used;
+		}
+	}
+
+	for (isize i = 0; i < entity_count; i++) {
+		add_entity(ctx->checker, ctx->scope, entities[i]->identifier, entities[i]);
+	}
+
+
+	// NOTE(bill): Minimize the amount of nesting of an 'inline for'
+	i64 prev_inline_for_depth = ctx->inline_for_depth;
+	defer (ctx->inline_for_depth = prev_inline_for_depth);
+	{
+		i64 v = exact_value_to_i64(inline_for_depth);
+		if (v <= 0) {
+			// Do nothing
+		} else {
+			ctx->inline_for_depth = gb_max(ctx->inline_for_depth, 1) * v;
+		}
+
+		if (ctx->inline_for_depth >= MAX_INLINE_FOR_DEPTH && prev_inline_for_depth < MAX_INLINE_FOR_DEPTH) {
+			if (prev_inline_for_depth > 0) {
+				error(node, "Nested 'inline for' loop cannot be inlined as it exceeds the maximum inline for depth (%lld levels >= %lld maximum levels)", v, MAX_INLINE_FOR_DEPTH);
+			} else {
+				error(node, "'inline for' loop cannot be inlined as it exceeds the maximum inline for depth (%lld levels >= %lld maximum levels)", v, MAX_INLINE_FOR_DEPTH);
+			}
+			error_line("\tUse a normal 'for' loop instead by removing the 'inline' prefix\n");
+			ctx->inline_for_depth = MAX_INLINE_FOR_DEPTH;
+		}
+	}
+
+	check_stmt(ctx, irs->body, mod_flags);
+
+
+	check_close_scope(ctx);
+}
+
 void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 	ast_node(ss, SwitchStmt, node);
 
@@ -971,7 +1130,7 @@ void check_type_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 					GB_PANIC("Unknown type to type switch statement");
 				}
 
-				if (ptr_set_exists(&seen, y.type)) {
+				if (type_ptr_set_exists(&seen, y.type)) {
 					TokenPos pos = cc->token.pos;
 					gbString expr_str = expr_to_string(y.expr);
 					error(y.expr,
@@ -1023,7 +1182,7 @@ void check_type_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 
 		for_array(i, variants) {
 			Type *t = variants[i];
-			if (!ptr_set_exists(&seen, t)) {
+			if (!type_ptr_set_exists(&seen, t)) {
 				array_add(&unhandled, t);
 			}
 		}
@@ -1132,7 +1291,8 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 			isize rhs_count = rhs_operands.count;
 			for_array(i, rhs_operands) {
 				if (rhs_operands[i].mode == Addressing_Invalid) {
-					rhs_count--;
+					// TODO(bill): Should I ignore invalid parameters?
+					// rhs_count--;
 				}
 			}
 
@@ -1168,7 +1328,7 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 			be->right = as->rhs[0];
 
 			check_expr(ctx, &lhs, as->lhs[0]);
-			check_binary_expr(ctx, &rhs, &binary_expr, true);
+			check_binary_expr(ctx, &rhs, &binary_expr, nullptr, true);
 			if (rhs.mode == Addressing_Invalid) {
 				return;
 			}
@@ -1298,6 +1458,7 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 		check_close_scope(ctx);
 	case_end;
 
+
 	case_ast_node(rs, RangeStmt, node);
 		u32 new_flags = mod_flags | Stmt_BreakAllowed | Stmt_ContinueAllowed;
 
@@ -1320,29 +1481,29 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 
 			check_expr(ctx, &x, ie->left);
 			if (x.mode == Addressing_Invalid) {
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 			check_expr(ctx, &y, ie->right);
 			if (y.mode == Addressing_Invalid) {
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 
 			convert_to_typed(ctx, &x, y.type);
 			if (x.mode == Addressing_Invalid) {
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 			convert_to_typed(ctx, &y, x.type);
 			if (y.mode == Addressing_Invalid) {
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 
 			convert_to_typed(ctx, &x, default_type(y.type));
 			if (x.mode == Addressing_Invalid) {
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 			convert_to_typed(ctx, &y, default_type(x.type));
 			if (y.mode == Addressing_Invalid) {
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 
 			if (!are_types_identical(x.type, y.type)) {
@@ -1356,13 +1517,13 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 					gb_string_free(yt);
 					gb_string_free(xt);
 				}
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 
 			Type *type = x.type;
 			if (!is_type_integer(type) && !is_type_float(type) && !is_type_pointer(type) && !is_type_enum(type)) {
 				error(ie->op, "Only numerical and pointer types are allowed within interval expressions");
-				goto skip_expr;
+				goto skip_expr_range_stmt;
 			}
 
 			if (x.mode == Addressing_Constant &&
@@ -1382,18 +1543,10 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 				if (!ok) {
 					// TODO(bill): Better error message
 					error(ie->op, "Invalid interval range");
-					goto skip_expr;
+					goto skip_expr_range_stmt;
 				}
 			}
 
-			if (x.mode != Addressing_Constant) {
-				x.value = empty_exact_value;
-			}
-			if (y.mode != Addressing_Constant) {
-				y.value = empty_exact_value;
-			}
-
-
 			add_type_and_value(&ctx->checker->info, ie->left,  x.mode, x.type, x.value);
 			add_type_and_value(&ctx->checker->info, ie->right, y.mode, y.type, y.value);
 			val0 = type;
@@ -1407,12 +1560,12 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 					gbString t = type_to_string(operand.type);
 					error(operand.expr, "Cannot iterate over the type '%s'", t);
 					gb_string_free(t);
-					goto skip_expr;
+					goto skip_expr_range_stmt;
 				} else {
 					val0 = operand.type;
 					val1 = t_int;
 					add_type_info_type(ctx, operand.type);
-					goto skip_expr;
+					goto skip_expr_range_stmt;
 				}
 			} else if (operand.mode != Addressing_Invalid) {
 				bool is_ptr = is_type_pointer(operand.type);
@@ -1457,7 +1610,8 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 			}
 		}
 
-	skip_expr:; // NOTE(zhiayang): again, declaring a variable immediately after a label... weird.
+		skip_expr_range_stmt:; // NOTE(zhiayang): again, declaring a variable immediately after a label... weird.
+
 		Ast * lhs[2] = {rs->val0, rs->val1};
 		Type *rhs[2] = {val0, val1};
 
@@ -1507,7 +1661,12 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 		}
 
 		for (isize i = 0; i < entity_count; i++) {
-			add_entity(ctx->checker, ctx->scope, entities[i]->identifier, entities[i]);
+			Entity *e = entities[i];
+			DeclInfo *d = decl_info_of_entity(e);
+			GB_ASSERT(d == nullptr);
+			add_entity(ctx->checker, ctx->scope, e->identifier, e);
+			d = make_decl_info(ctx->allocator, ctx->scope, ctx->decl);
+			add_entity_and_decl_info(ctx, e->identifier, e, d);
 		}
 
 		check_stmt(ctx, rs->body, new_flags);
@@ -1515,6 +1674,10 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 		check_close_scope(ctx);
 	case_end;
 
+	case_ast_node(irs, InlineRangeStmt, node);
+		check_inline_range_stmt(ctx, node, mod_flags);
+	case_end;
+
 	case_ast_node(ss, SwitchStmt, node);
 		check_switch_stmt(ctx, node, mod_flags);
 	case_end;
@@ -1814,7 +1977,7 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 					// TODO(bill): Should a 'continue' happen here?
 				}
 
-				for (isize entity_index = 0; entity_index < entity_count; entity_index++) {
+				for (isize entity_index = 0; entity_index < 1; entity_index++) {
 					Entity *e = entities[entity_index];
 					if (e == nullptr) {
 						continue;
@@ -1833,7 +1996,7 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 						for_array(i, scope->elements.entries) {
 							Entity *f = scope->elements.entries[i].value;
 							if (f->kind == Entity_Variable) {
-								Entity *uvar = alloc_entity_using_variable(e, f->token, f->type);
+								Entity *uvar = alloc_entity_using_variable(e, f->token, f->type, nullptr);
 								uvar->Variable.is_immutable = is_immutable;
 								Entity *prev = scope_insert(ctx->scope, uvar);
 								if (prev != nullptr) {
diff --git a/src/check_type.cpp b/src/check_type.cpp
index f4e5b49d0..9f8310e44 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -110,9 +110,10 @@ bool does_field_type_allow_using(Type *t) {
 	return false;
 }
 
-void check_struct_fields(CheckerContext *ctx, Ast *node, Array<Entity *> *fields, Array<Ast *> const &params,
+void check_struct_fields(CheckerContext *ctx, Ast *node, Array<Entity *> *fields, Array<String> *tags, Array<Ast *> const &params,
                          isize init_field_capacity, Type *struct_type, String context) {
 	*fields = array_make<Entity *>(heap_allocator(), 0, init_field_capacity);
+	*tags   = array_make<String>(heap_allocator(), 0, init_field_capacity);
 
 	GB_ASSERT(node->kind == Ast_StructType);
 	GB_ASSERT(struct_type->kind == Type_Struct);
@@ -171,6 +172,7 @@ void check_struct_fields(CheckerContext *ctx, Ast *node, Array<Entity *> *fields
 			Entity *field = alloc_entity_field(ctx->scope, name_token, type, is_using, field_src_index);
 			add_entity(ctx->checker, ctx->scope, name, field);
 			array_add(fields, field);
+			array_add(tags, p->tag.string);
 
 			field_src_index += 1;
 		}
@@ -246,38 +248,51 @@ bool check_custom_align(CheckerContext *ctx, Ast *node, i64 *align_) {
 }
 
 
-Entity *find_polymorphic_record_entity(CheckerContext *ctx, Type *original_type, isize param_count, Array<Operand> ordered_operands) {
+Entity *find_polymorphic_record_entity(CheckerContext *ctx, Type *original_type, isize param_count, Array<Operand> const &ordered_operands, bool *failure) {
 	auto *found_gen_types = map_get(&ctx->checker->info.gen_types, hash_pointer(original_type));
 	if (found_gen_types != nullptr) {
 		for_array(i, *found_gen_types) {
 			Entity *e = (*found_gen_types)[i];
 			Type *t = base_type(e->type);
 			TypeTuple *tuple = get_record_polymorphic_params(t);
-			bool ok = true;
 			GB_ASSERT(param_count == tuple->variables.count);
+
+			bool skip = false;
+
 			for (isize j = 0; j < param_count; j++) {
 				Entity *p = tuple->variables[j];
 				Operand o = ordered_operands[j];
+				Entity *oe = entity_of_node(o.expr);
+				if (p == oe) {
+					// NOTE(bill): This is the same type, make sure that it will be be same thing and use that
+					// Saves on a lot of checking too below
+					continue;
+				}
+
 				if (p->kind == Entity_TypeName) {
 					if (is_type_polymorphic(o.type)) {
 						// NOTE(bill): Do not add polymorphic version to the gen_types
-						ok = false;
+						skip = true;
+						break;
 					}
 					if (!are_types_identical(o.type, p->type)) {
-						ok = false;
+						skip = true;
+						break;
 					}
 				} else if (p->kind == Entity_Constant) {
-					if (!are_types_identical(o.type, p->type)) {
-						ok = false;
-					}
 					if (!compare_exact_values(Token_CmpEq, o.value, p->Constant.value)) {
-						ok = false;
+						skip = true;
+						break;
+					}
+					if (!are_types_identical(o.type, p->type)) {
+						skip = true;
+						break;
 					}
 				} else {
 					GB_PANIC("Unknown entity kind");
 				}
 			}
-			if (ok) {
+			if (!skip) {
 				return e;
 			}
 		}
@@ -439,8 +454,6 @@ void check_struct_type(CheckerContext *ctx, Type *struct_type, Ast *node, Array<
 					if (poly_operands != nullptr) {
 						Operand operand = (*poly_operands)[entities.count];
 						if (is_type_param) {
-							GB_ASSERT(operand.mode == Addressing_Type ||
-							          operand.mode == Addressing_Invalid);
 							if (is_type_polymorphic(base_type(operand.type))) {
 								is_polymorphic = true;
 								can_check_fields = false;
@@ -448,6 +461,10 @@ void check_struct_type(CheckerContext *ctx, Type *struct_type, Ast *node, Array<
 							e = alloc_entity_type_name(scope, token, operand.type);
 							e->TypeName.is_type_alias = true;
 						} else {
+							if (is_type_polymorphic(base_type(operand.type))) {
+								is_polymorphic = true;
+								can_check_fields = false;
+							}
 							e = alloc_entity_constant(scope, token, operand.type, operand.value);
 						}
 					} else {
@@ -502,9 +519,13 @@ void check_struct_type(CheckerContext *ctx, Type *struct_type, Ast *node, Array<
 	struct_type->Struct.polymorphic_params      = polymorphic_params;
 	struct_type->Struct.is_poly_specialized     = is_poly_specialized;
 
-
 	if (!is_polymorphic) {
-		check_struct_fields(ctx, node, &struct_type->Struct.fields, st->fields, min_field_count, struct_type, context);
+		if (st->where_clauses.count > 0 && st->polymorphic_params == nullptr) {
+			error(st->where_clauses[0], "'where' clauses can only be used on structures with polymorphic parameters");
+		} else {
+			bool where_clause_ok = evaluate_where_clauses(ctx, ctx->scope, &st->where_clauses, true);
+		}
+		check_struct_fields(ctx, node, &struct_type->Struct.fields, &struct_type->Struct.tags, st->fields, min_field_count, struct_type, context);
 	}
 
 	if (st->align != nullptr) {
@@ -686,6 +707,13 @@ void check_union_type(CheckerContext *ctx, Type *union_type, Ast *node, Array<Op
 	union_type->Union.is_polymorphic          = is_polymorphic;
 	union_type->Union.is_poly_specialized     = is_poly_specialized;
 
+	if (ut->where_clauses.count > 0 && ut->polymorphic_params == nullptr) {
+		error(ut->where_clauses[0], "'where' clauses can only be used on unions with polymorphic parameters");
+	} else {
+		bool where_clause_ok = evaluate_where_clauses(ctx, ctx->scope, &ut->where_clauses, true);
+	}
+
+
 	for_array(i, ut->variants) {
 		Ast *node = ut->variants[i];
 		Type *t = check_type_expr(ctx, node, nullptr);
@@ -1252,20 +1280,21 @@ bool check_type_specialization_to(CheckerContext *ctx, Type *specialization, Typ
 
 Type *determine_type_from_polymorphic(CheckerContext *ctx, Type *poly_type, Operand operand) {
 	bool modify_type = !ctx->no_polymorphic_errors;
+	bool show_error = modify_type && !ctx->hide_polymorphic_errors;
 	if (!is_operand_value(operand)) {
-		if (modify_type) {
+		if (show_error) {
 			error(operand.expr, "Cannot determine polymorphic type from parameter");
 		}
 		return t_invalid;
 	}
 
 	if (is_polymorphic_type_assignable(ctx, poly_type, operand.type, false, modify_type)) {
-		if (modify_type) {
-			set_procedure_abi_types(ctx, poly_type);
+		if (show_error) {
+			set_procedure_abi_types(ctx->allocator, poly_type);
 		}
 		return poly_type;
 	}
-	if (modify_type) {
+	if (show_error) {
 		gbString pts = type_to_string(poly_type);
 		gbString ots = type_to_string(operand.type);
 		defer (gb_string_free(pts));
@@ -1538,7 +1567,7 @@ Type *check_get_params(CheckerContext *ctx, Scope *scope, Ast *_params, bool *is
 			}
 
 			if (is_poly_name) {
-				if (type != nullptr && type_expr->kind == Ast_TypeidType) {
+				if (type_expr != nullptr && type_expr->kind == Ast_TypeidType) {
 					is_type_param = true;
 				} else {
 					if (param_value.kind != ParameterValue_Invalid)  {
@@ -1622,6 +1651,7 @@ Type *check_get_params(CheckerContext *ctx, Scope *scope, Ast *_params, bool *is
 						if (op.mode == Addressing_Constant) {
 							poly_const = op.value;
 						} else {
+							error(op.expr, "Expected a constant value for this polymorphic name parameter");
 							success = false;
 						}
 					}
@@ -1825,6 +1855,282 @@ Type *check_get_results(CheckerContext *ctx, Scope *scope, Ast *_results) {
 	return tuple;
 }
 
+Array<Type *> systemv_distribute_struct_fields(Type *t) {
+	Type *bt = core_type(t);
+
+
+	isize distributed_cap = 1;
+	if (bt->kind == Type_Struct) {
+		distributed_cap = bt->Struct.fields.count;
+	}
+	auto distributed = array_make<Type *>(heap_allocator(), 0, distributed_cap);
+
+	i64 sz = type_size_of(bt);
+	switch (bt->kind) {
+	case Type_Basic:
+		switch (bt->Basic.kind){
+		case Basic_complex64:
+			array_add(&distributed, t_f32);
+			array_add(&distributed, t_f32);
+			break;
+		case Basic_complex128:
+			array_add(&distributed, t_f64);
+			array_add(&distributed, t_f64);
+			break;
+		case Basic_quaternion128:
+			array_add(&distributed, t_f32);
+			array_add(&distributed, t_f32);
+			array_add(&distributed, t_f32);
+			array_add(&distributed, t_f32);
+			break;
+		case Basic_quaternion256:
+			goto DEFAULT;
+		case Basic_string:
+			array_add(&distributed, t_u8_ptr);
+			array_add(&distributed, t_int);
+			break;
+		case Basic_any:
+			GB_ASSERT(type_size_of(t_uintptr) == type_size_of(t_typeid));
+			array_add(&distributed, t_rawptr);
+			array_add(&distributed, t_uintptr);
+			break;
+
+		case Basic_u128:
+		case Basic_i128:
+			if (build_context.ODIN_OS == "windows") {
+				array_add(&distributed, alloc_type_simd_vector(2, t_u64));
+			} else {
+				array_add(&distributed, bt);
+			}
+			break;
+
+		default:
+			goto DEFAULT;
+		}
+		break;
+
+	case Type_Struct:
+		if (bt->Struct.is_raw_union) {
+			goto DEFAULT;
+		} else {
+			// IMPORTANT TOOD(bill): handle #packed structs correctly
+			// IMPORTANT TODO(bill): handle #align structs correctly
+			for_array(field_index, bt->Struct.fields) {
+				Entity *f = bt->Struct.fields[field_index];
+				auto nested = systemv_distribute_struct_fields(f->type);
+				array_add_elems(&distributed, nested.data, nested.count);
+				array_free(&nested);
+			}
+		}
+		break;
+
+	case Type_Array:
+		for (i64 i = 0; i < bt->Array.count; i++) {
+			array_add(&distributed, bt->Array.elem);
+		}
+		break;
+
+	case Type_BitSet:
+		array_add(&distributed, bit_set_to_int(bt));
+		break;
+
+	case Type_Tuple:
+		GB_PANIC("Invalid struct field type");
+		break;
+
+	case Type_Slice:
+		array_add(&distributed, t_rawptr);
+		array_add(&distributed, t_int);
+		break;
+
+	case Type_Union:
+	case Type_DynamicArray:
+	case Type_Map:
+	case Type_BitField: // TODO(bill): Ignore?
+		// NOTE(bill, 2019-10-10): Odin specific, don't worry about C calling convention yet
+		goto DEFAULT;
+
+	case Type_Pointer:
+	case Type_Proc:
+	case Type_SimdVector: // TODO(bill): Is this correct logic?
+	default:
+	DEFAULT:;
+		if (sz > 0) {
+			array_add(&distributed, bt);
+		}
+		break;
+	}
+
+	return distributed;
+}
+
+Type *struct_type_from_systemv_distribute_struct_fields(Type *abi_type) {
+	GB_ASSERT(is_type_tuple(abi_type));
+	Type *final_type = alloc_type_struct();
+	final_type->Struct.fields = abi_type->Tuple.variables;
+	return final_type;
+}
+
+
+Type *handle_single_distributed_type_parameter(Array<Type *> const &types, bool packed, isize *offset) {
+	GB_ASSERT(types.count > 0);
+
+	if (types.count == 1) {
+		if (offset) *offset = 1;
+
+		i64 sz = type_size_of(types[0]);
+
+		if (is_type_float(types[0])) {
+			return types[0];
+		}
+		switch (sz) {
+		case 0:
+			GB_PANIC("Zero sized type found!");
+		case 1: return t_u8;
+		case 2: return t_u16;
+		case 4: return t_u32;
+		case 8: return t_u64;
+		default:
+			return types[0];
+		}
+	} else if (types.count >= 2) {
+	    if (types[0] == t_f32 && types[1] == t_f32) {
+	    	if (offset) *offset = 2;
+			return alloc_type_simd_vector(2, t_f32);
+		} else if (type_size_of(types[0]) == 8) {
+	    	if (offset) *offset = 1;
+			return types[0];
+		}
+
+		i64 total_size = 0;
+		isize i = 0;
+		if (packed) {
+			for (; i < types.count && total_size < 8; i += 1) {
+				Type *t = types[i];
+				i64 s = type_size_of(t);
+				total_size += s;
+			}
+		} else {
+			for (; i < types.count && total_size < 8; i += 1) {
+				Type *t = types[i];
+				i64 s = gb_max(type_size_of(t), 0);
+				i64 a = gb_max(type_align_of(t), 1);
+				isize ts = align_formula(total_size, a);
+				if (ts >= 8) {
+					break;
+				}
+				total_size = ts + s;
+			}
+		}
+		if (offset) *offset = i;
+		switch (total_size) {
+		case 1: return t_u8;
+		case 2: return t_u16;
+		case 4: return t_u32;
+		case 8: return t_u64;
+		}
+		return t_u64;
+	}
+
+	return nullptr;
+}
+
+Type *handle_struct_system_v_amd64_abi_type(Type *t) {
+	if (type_size_of(t) > 16) {
+		return alloc_type_pointer(t);
+	}
+	Type *original_type = t;
+	Type *bt = core_type(t);
+	t = base_type(t);
+	i64 size = type_size_of(bt);
+
+	switch (t->kind) {
+	case Type_Slice:
+	case Type_Struct:
+		break;
+
+	case Type_Basic:
+		switch (bt->Basic.kind) {
+		case Basic_string:
+		case Basic_any:
+		case Basic_complex64:
+		case Basic_complex128:
+		case Basic_quaternion128:
+			break;
+		default:
+			return original_type;
+		}
+		break;
+
+	default:
+		return original_type;
+	}
+
+	bool is_packed = false;
+	if (is_type_struct(bt)) {
+		is_packed = bt->Struct.is_packed;
+	}
+
+	if (is_type_raw_union(bt)) {
+		// TODO(bill): Handle raw union correctly for
+		return t;
+	} else {
+		auto field_types = systemv_distribute_struct_fields(bt);
+		defer (array_free(&field_types));
+
+		GB_ASSERT(field_types.count <= 16);
+
+		Type *final_type = nullptr;
+
+		if (field_types.count == 0) {
+			final_type = t;
+		} else if (field_types.count == 1) {
+			final_type = field_types[0];
+		} else {
+			if (size <= 8) {
+				isize offset = 0;
+				final_type = handle_single_distributed_type_parameter(field_types, is_packed, &offset);
+			} else {
+				isize offset = 0;
+				isize next_offset = 0;
+				Type *two_types[2] = {};
+
+				two_types[0] = handle_single_distributed_type_parameter(field_types, is_packed, &offset);
+				auto remaining = array_slice(field_types, offset, field_types.count);
+				two_types[1] = handle_single_distributed_type_parameter(remaining, is_packed, &next_offset);
+				GB_ASSERT(offset + next_offset == field_types.count);
+
+				auto variables = array_make<Entity *>(heap_allocator(), 2);
+				variables[0] = alloc_entity_param(nullptr, empty_token, two_types[0], false, false);
+				variables[1] = alloc_entity_param(nullptr, empty_token, two_types[1], false, false);
+				final_type = alloc_type_tuple();
+				final_type->Tuple.variables = variables;
+				if (t->kind == Type_Struct) {
+					// NOTE(bill): Make this packed
+					final_type->Tuple.is_packed = t->Struct.is_packed;
+				}
+			}
+		}
+
+
+		GB_ASSERT(final_type != nullptr);
+		i64 ftsz = type_size_of(final_type);
+		i64 otsz = type_size_of(original_type);
+		if (ftsz != otsz) {
+			// TODO(bill): Handle this case which will be caused by #packed most likely
+			switch (otsz) {
+			case 1:
+			case 2:
+			case 4:
+			case 8:
+				GB_PANIC("Incorrectly handled case for handle_struct_system_v_amd64_abi_type, %s %lld vs %s %lld", type_to_string(final_type), ftsz, type_to_string(original_type), otsz);
+			}
+		}
+
+		return final_type;
+	}
+}
+
 Type *type_to_abi_compat_param_type(gbAllocator a, Type *original_type, ProcCallingConvention cc) {
 	Type *new_type = original_type;
 
@@ -1889,6 +2195,7 @@ Type *type_to_abi_compat_param_type(gbAllocator a, Type *original_type, ProcCall
 		{
 			i64 align = type_align_of(original_type);
 			i64 size  = type_size_of(original_type);
+
 			switch (8*size) {
 			case 8:  new_type = t_u8;  break;
 			case 16: new_type = t_u16; break;
@@ -1903,7 +2210,7 @@ Type *type_to_abi_compat_param_type(gbAllocator a, Type *original_type, ProcCall
 		}
 		}
 	} else if (build_context.ODIN_OS == "linux" ||
-	           build_context.ODIN_OS == "osx") {
+	           build_context.ODIN_OS == "darwin") {
 		Type *bt = core_type(original_type);
 		switch (bt->kind) {
 		// Okay to pass by value (usually)
@@ -1920,18 +2227,17 @@ Type *type_to_abi_compat_param_type(gbAllocator a, Type *original_type, ProcCall
 		case Type_Pointer: break;
 		case Type_Proc:    break; // NOTE(bill): Just a pointer
 
-		// Odin specific
-		case Type_Slice:
-		case Type_Array:
-		case Type_DynamicArray:
-		case Type_Map:
-		case Type_Union:
-		// Could be in C too
-		case Type_Struct: {
-			i64 align = type_align_of(original_type);
-			i64 size  = type_size_of(original_type);
-			if (8*size > 16) {
+		default: {
+			i64 size = type_size_of(original_type);
+			if (size > 16) {
 				new_type = alloc_type_pointer(original_type);
+			} else if (build_context.ODIN_ARCH == "amd64") {
+				// NOTE(bill): System V AMD64 ABI
+				new_type = handle_struct_system_v_amd64_abi_type(bt);
+				if (are_types_identical(core_type(original_type), new_type)) {
+					new_type = original_type;
+				}
+				return new_type;
 			}
 
 			break;
@@ -2004,8 +2310,10 @@ Type *type_to_abi_compat_result_type(gbAllocator a, Type *original_type, ProcCal
 			break;
 		}
 		}
-	} else if (build_context.ODIN_OS == "linux") {
+	} else if (build_context.ODIN_OS == "linux" || build_context.ODIN_OS == "darwin") {
+		if (build_context.ODIN_ARCH == "amd64") {
 
+		}
 	} else {
 		// IMPORTANT TODO(bill): figure out the ABI settings for Linux, OSX etc. for
 		// their architectures
@@ -2071,25 +2379,39 @@ bool abi_compat_return_by_pointer(gbAllocator a, ProcCallingConvention cc, Type
 	return false;
 }
 
-void set_procedure_abi_types(CheckerContext *c, Type *type) {
+void set_procedure_abi_types(gbAllocator allocator, Type *type) {
 	type = base_type(type);
 	if (type->kind != Type_Proc) {
 		return;
 	}
 
-	type->Proc.abi_compat_params = array_make<Type *>(c->allocator, cast(isize)type->Proc.param_count);
+	if (type->Proc.abi_types_set) {
+		return;
+	}
+
+	type->Proc.abi_compat_params = array_make<Type *>(allocator, cast(isize)type->Proc.param_count);
 	for (i32 i = 0; i < type->Proc.param_count; i++) {
 		Entity *e = type->Proc.params->Tuple.variables[i];
 		if (e->kind == Entity_Variable) {
 			Type *original_type = e->type;
-			Type *new_type = type_to_abi_compat_param_type(c->allocator, original_type, type->Proc.calling_convention);
+			Type *new_type = type_to_abi_compat_param_type(allocator, original_type, type->Proc.calling_convention);
 			type->Proc.abi_compat_params[i] = new_type;
+			switch (type->Proc.calling_convention) {
+			case ProcCC_Odin:
+			case ProcCC_Contextless:
+				if (is_type_pointer(new_type) & !is_type_pointer(e->type)) {
+					e->flags |= EntityFlag_ImplicitReference;
+				}
+				break;
+			}
 		}
 	}
 
 	// NOTE(bill): The types are the same
-	type->Proc.abi_compat_result_type = type_to_abi_compat_result_type(c->allocator, type->Proc.results, type->Proc.calling_convention);
-	type->Proc.return_by_pointer = abi_compat_return_by_pointer(c->allocator, type->Proc.calling_convention, type->Proc.abi_compat_result_type);
+	type->Proc.abi_compat_result_type = type_to_abi_compat_result_type(allocator, type->Proc.results, type->Proc.calling_convention);
+	type->Proc.return_by_pointer = abi_compat_return_by_pointer(allocator, type->Proc.calling_convention, type->Proc.abi_compat_result_type);
+
+	type->Proc.abi_types_set = true;
 }
 
 // NOTE(bill): 'operands' is for generating non generic procedure type
@@ -2187,8 +2509,6 @@ bool check_procedure_type(CheckerContext *ctx, Type *type, Ast *proc_type_node,
 	}
 	type->Proc.is_polymorphic = is_polymorphic;
 
-	set_procedure_abi_types(c, type);
-
 	return success;
 }
 
@@ -2537,7 +2857,7 @@ bool check_type_internal(CheckerContext *ctx, Ast *e, Type **type, Type *named_t
 				generic_type = o.type;
 			}
 			if (count < 0) {
-				error(at->count, "... can only be used in conjuction with compound literals");
+				error(at->count, "? can only be used in conjuction with compound literals");
 				count = 0;
 			}
 			Type *elem = check_type_expr(ctx, at->elem, nullptr);
diff --git a/src/checker.cpp b/src/checker.cpp
index 9abd8c499..e7b347f1a 100644
--- a/src/checker.cpp
+++ b/src/checker.cpp
@@ -85,9 +85,13 @@ int entity_graph_node_cmp(EntityGraphNode **data, isize i, isize j) {
 	EntityGraphNode *y = data[j];
 	isize a = x->entity->order_in_src;
 	isize b = y->entity->order_in_src;
-	if (x->dep_count < y->dep_count) return -1;
-	if (x->dep_count > y->dep_count) return +1;
-	return a < b ? -1 : b > a;
+	if (x->dep_count < y->dep_count) {
+		return -1;
+	}
+	if (x->dep_count == y->dep_count) {
+		return a < b ? -1 : b > a;
+	}
+	return +1;
 }
 
 void entity_graph_node_swap(EntityGraphNode **data, isize i, isize j) {
@@ -400,6 +404,15 @@ Entity *scope_insert_with_name(Scope *s, String name, Entity *entity) {
 	if (found) {
 		return *found;
 	}
+	if (s->parent != nullptr && (s->parent->flags & ScopeFlag_Proc) != 0) {
+		Entity **found = map_get(&s->parent->elements, key);
+		if (found) {
+			if ((*found)->flags & EntityFlag_Result) {
+				return *found;
+			}
+		}
+	}
+
 	map_set(&s->elements, key, entity);
 	if (entity->scope == nullptr) {
 		entity->scope = s;
@@ -1044,21 +1057,37 @@ bool redeclaration_error(String name, Entity *prev, Entity *found) {
 			// NOTE(bill): Error should have been handled already
 			return false;
 		}
-		error(prev->token,
-		      "Redeclaration of '%.*s' in this scope through 'using'\n"
-		      "\tat %.*s(%td:%td)",
-		      LIT(name),
-		      LIT(up->token.pos.file), up->token.pos.line, up->token.pos.column);
+		if (found->flags & EntityFlag_Result) {
+			error(prev->token,
+			      "Direct shadowing of the named return value '%.*s' in this scope through 'using'\n"
+			      "\tat %.*s(%td:%td)",
+			      LIT(name),
+			      LIT(up->token.pos.file), up->token.pos.line, up->token.pos.column);
+		} else {
+			error(prev->token,
+			      "Redeclaration of '%.*s' in this scope through 'using'\n"
+			      "\tat %.*s(%td:%td)",
+			      LIT(name),
+			      LIT(up->token.pos.file), up->token.pos.line, up->token.pos.column);
+		}
 	} else {
 		if (pos == prev->token.pos) {
 			// NOTE(bill): Error should have been handled already
 			return false;
 		}
-		error(prev->token,
-		      "Redeclaration of '%.*s' in this scope\n"
-		      "\tat %.*s(%td:%td)",
-		      LIT(name),
-		      LIT(pos.file), pos.line, pos.column);
+		if (found->flags & EntityFlag_Result) {
+			error(prev->token,
+			      "Direct shadowing of the named return value '%.*s' in this scope\n"
+			      "\tat %.*s(%td:%td)",
+			      LIT(name),
+			      LIT(pos.file), pos.line, pos.column);
+		} else {
+			error(prev->token,
+			      "Redeclaration of '%.*s' in this scope\n"
+			      "\tat %.*s(%td:%td)",
+			      LIT(name),
+			      LIT(pos.file), pos.line, pos.column);
+		}
 	}
 	return false;
 }
@@ -1139,6 +1168,7 @@ void add_entity_and_decl_info(CheckerContext *c, Ast *identifier, Entity *e, Dec
 	add_entity_definition(&c->checker->info, identifier, e);
 	GB_ASSERT(e->decl_info == nullptr);
 	e->decl_info = d;
+	d->entity = e;
 	array_add(&c->checker->info.entities, e);
 	e->order_in_src = c->checker->info.entities.count;
 	e->pkg = c->pkg;
@@ -1415,6 +1445,14 @@ void add_min_dep_type_info(Checker *c, Type *t) {
 			add_min_dep_type_info(c, t_type_info_float);
 			add_min_dep_type_info(c, t_f64);
 			break;
+		case Basic_quaternion128:
+			add_min_dep_type_info(c, t_type_info_float);
+			add_min_dep_type_info(c, t_f32);
+			break;
+		case Basic_quaternion256:
+			add_min_dep_type_info(c, t_type_info_float);
+			add_min_dep_type_info(c, t_f64);
+			break;
 		}
 		break;
 
@@ -1577,6 +1615,7 @@ void generate_minimum_dependency_set(Checker *c, Entity *start) {
 
 		str_lit("args__"),
 		str_lit("type_table"),
+		str_lit("__type_info_of"),
 		str_lit("global_scratch_allocator"),
 
 		str_lit("Type_Info"),
@@ -1585,9 +1624,17 @@ void generate_minimum_dependency_set(Checker *c, Entity *start) {
 
 		str_lit("quo_complex64"),
 		str_lit("quo_complex128"),
+		str_lit("mul_quaternion128"),
+		str_lit("mul_quaternion256"),
+		str_lit("quo_quaternion128"),
+		str_lit("quo_quaternion256"),
+		str_lit("cstring_to_string"),
 
 		str_lit("umodti3"),
 		str_lit("udivti3"),
+
+		str_lit("memory_compare"),
+		str_lit("memory_compare_zero"),
 	};
 	for (isize i = 0; i < gb_count_of(required_runtime_entities); i++) {
 		add_dependency_to_set(c, scope_lookup(c->info.runtime_package->scope, required_runtime_entities[i]));
@@ -1656,9 +1703,10 @@ bool is_entity_a_dependency(Entity *e) {
 	if (e == nullptr) return false;
 	switch (e->kind) {
 	case Entity_Procedure:
-	case Entity_Variable:
-	case Entity_Constant:
 		return true;
+	case Entity_Constant:
+	case Entity_Variable:
+		return e->pkg != nullptr;
 	}
 	return false;
 }
@@ -1685,18 +1733,17 @@ Array<EntityGraphNode *> generate_entity_dependency_graph(CheckerInfo *info) {
 		EntityGraphNode *n = M.entries[i].value;
 
 		DeclInfo *decl = decl_info_of_entity(e);
-		if (decl != nullptr) {
-			for_array(j, decl->deps.entries) {
-				auto entry = decl->deps.entries[j];
-				Entity *dep = entry.ptr;
-				if (dep && is_entity_a_dependency(dep)) {
-					EntityGraphNode **m_ = map_get(&M, hash_pointer(dep));
-					if (m_ != nullptr) {
-						EntityGraphNode *m = *m_;
-						entity_graph_node_set_add(&n->succ, m);
-						entity_graph_node_set_add(&m->pred, n);
-					}
-				}
+		GB_ASSERT(decl != nullptr);
+
+		for_array(j, decl->deps.entries) {
+			Entity *dep = decl->deps.entries[j].ptr;
+			GB_ASSERT(dep != nullptr);
+			if (is_entity_a_dependency(dep)) {
+				EntityGraphNode **m_ = map_get(&M, hash_pointer(dep));
+				GB_ASSERT(m_ != nullptr);
+				EntityGraphNode *m = *m_;
+				entity_graph_node_set_add(&n->succ, m);
+				entity_graph_node_set_add(&m->pred, n);
 			}
 		}
 	}
@@ -1741,6 +1788,7 @@ Array<EntityGraphNode *> generate_entity_dependency_graph(CheckerInfo *info) {
 		EntityGraphNode *n = G[i];
 		n->index = i;
 		n->dep_count = n->succ.entries.count;
+
 		GB_ASSERT(n->dep_count >= 0);
 	}
 
@@ -1863,6 +1911,7 @@ void init_core_type_info(Checker *c) {
 	t_type_info_integer       = find_core_type(c, str_lit("Type_Info_Integer"));
 	t_type_info_rune          = find_core_type(c, str_lit("Type_Info_Rune"));
 	t_type_info_float         = find_core_type(c, str_lit("Type_Info_Float"));
+	t_type_info_quaternion    = find_core_type(c, str_lit("Type_Info_Quaternion"));
 	t_type_info_complex       = find_core_type(c, str_lit("Type_Info_Complex"));
 	t_type_info_string        = find_core_type(c, str_lit("Type_Info_String"));
 	t_type_info_boolean       = find_core_type(c, str_lit("Type_Info_Boolean"));
@@ -1887,6 +1936,7 @@ void init_core_type_info(Checker *c) {
 	t_type_info_integer_ptr       = alloc_type_pointer(t_type_info_integer);
 	t_type_info_rune_ptr          = alloc_type_pointer(t_type_info_rune);
 	t_type_info_float_ptr         = alloc_type_pointer(t_type_info_float);
+	t_type_info_quaternion_ptr    = alloc_type_pointer(t_type_info_quaternion);
 	t_type_info_complex_ptr       = alloc_type_pointer(t_type_info_complex);
 	t_type_info_string_ptr        = alloc_type_pointer(t_type_info_string);
 	t_type_info_boolean_ptr       = alloc_type_pointer(t_type_info_boolean);
@@ -2138,6 +2188,12 @@ DECL_ATTRIBUTE_PROC(proc_decl_attribute) {
 			error(elem, "Expected a string value for '%.*s'", LIT(name));
 		}
 		return true;
+	} else if (name == "require_results") {
+		if (value != nullptr) {
+			error(elem, "Expected no value for '%.*s'", LIT(name));
+		}
+		ac->require_results = true;
+		return true;
 	}
 	return false;
 }
@@ -2528,6 +2584,7 @@ void check_collect_value_decl(CheckerContext *c, Ast *decl) {
 
 			Ast *init_expr = value;
 			DeclInfo *d = make_decl_info(heap_allocator(), c->scope, c->decl);
+			d->entity    = e;
 			d->type_expr = vd->type;
 			d->init_expr = init_expr;
 			d->attributes = vd->attributes;
@@ -2557,14 +2614,14 @@ void check_collect_value_decl(CheckerContext *c, Ast *decl) {
 			Entity *e = nullptr;
 
 			d->attributes = vd->attributes;
+			d->type_expr = vd->type;
+			d->init_expr = init;
 
 			if (is_ast_type(init)) {
 				e = alloc_entity_type_name(d->scope, token, nullptr);
-				if (vd->type != nullptr) {
-					error(name, "A type declaration cannot have an type parameter");
-				}
-				d->type_expr = init;
-				d->init_expr = init;
+				// if (vd->type != nullptr) {
+				// 	error(name, "A type declaration cannot have an type parameter");
+				// }
 			} else if (init->kind == Ast_ProcLit) {
 				if (c->scope->flags&ScopeFlag_Type) {
 					error(name, "Procedure declarations are not allowed within a struct");
@@ -2591,19 +2648,15 @@ void check_collect_value_decl(CheckerContext *c, Ast *decl) {
 					pl->type->ProcType.calling_convention = cc;
 				}
 				d->proc_lit = init;
-				d->type_expr = vd->type;
+				d->init_expr = init;
 			} else if (init->kind == Ast_ProcGroup) {
 				ast_node(pg, ProcGroup, init);
 				e = alloc_entity_proc_group(d->scope, token, nullptr);
 				if (fl != nullptr) {
 					error(name, "Procedure groups are not allowed within a foreign block");
 				}
-				d->init_expr = init;
-				d->type_expr = vd->type;
 			} else {
 				e = alloc_entity_constant(d->scope, token, nullptr, empty_exact_value);
-				d->type_expr = vd->type;
-				d->init_expr = init;
 			}
 			e->identifier = name;
 
@@ -3101,7 +3154,7 @@ void check_add_import_decl(CheckerContext *ctx, Ast *decl) {
 			Entity *e = scope->elements.entries[elem_index].value;
 			if (e->scope == parent_scope) continue;
 
-			if (is_entity_exported(e)) {
+			if (is_entity_exported(e, true)) {
 				Entity *found = scope_lookup_current(parent_scope, name);
 				if (found != nullptr) {
 					// NOTE(bill):
@@ -3315,8 +3368,9 @@ bool collect_file_decls(CheckerContext *ctx, Array<Ast *> const &decls) {
 			if (es->expr->kind == Ast_CallExpr) {
 				ast_node(ce, CallExpr, es->expr);
 				if (ce->proc->kind == Ast_BasicDirective) {
-					Operand o = {};
-					check_expr(ctx, &o, es->expr);
+					if (ctx->collect_delayed_decls) {
+						array_add(&ctx->scope->delayed_directives, es->expr);
+					}
 				}
 			}
 		case_end;
@@ -3473,12 +3527,18 @@ void check_import_entities(Checker *c) {
 		for_array(i, pkg->files) {
 			AstFile *f = pkg->files[i];
 			CheckerContext ctx = c->init_ctx;
-
 			add_curr_ast_file(&ctx, f);
+
 			for_array(j, f->scope->delayed_imports) {
 				Ast *decl = f->scope->delayed_imports[j];
 				check_add_import_decl(&ctx, decl);
 			}
+		}
+		for_array(i, pkg->files) {
+			AstFile *f = pkg->files[i];
+			CheckerContext ctx = c->init_ctx;
+			add_curr_ast_file(&ctx, f);
+
 			for_array(j, f->scope->delayed_directives) {
 				Ast *expr = f->scope->delayed_directives[j];
 				Operand o = {};
@@ -3542,7 +3602,6 @@ void calculate_global_init_order(Checker *c) {
 #define TIME_SECTION(str)
 #endif
 
-
 	CheckerInfo *info = &c->info;
 
 	TIME_SECTION("generate entity dependency graph");
@@ -3584,21 +3643,26 @@ void calculate_global_init_order(Checker *c) {
 
 		for_array(i, n->pred.entries) {
 			EntityGraphNode *p = n->pred.entries[i].ptr;
-			p->dep_count -= gb_max(p->dep_count-1, 0);
+			p->dep_count -= 1;
+			p->dep_count = gb_max(p->dep_count, 0);
 			priority_queue_fix(&pq, p->index);
 		}
 
-		if (e == nullptr || e->kind != Entity_Variable) {
+		DeclInfo *d = decl_info_of_entity(e);
+		if (e->kind != Entity_Variable) {
 			continue;
 		}
-		DeclInfo *d = decl_info_of_entity(e);
-
+		// IMPORTANT NOTE(bill, 2019-08-29): Just add it regardless of the ordering
+		// because it does not need any initialization other than zero
+		// if (!decl_info_has_init(d)) {
+		// 	continue;
+		// }
 		if (ptr_set_exists(&emitted, d)) {
 			continue;
 		}
 		ptr_set_add(&emitted, d);
 
-		d->entity = e;
+
 		array_add(&info->variable_init_order, d);
 	}
 
@@ -3637,6 +3701,14 @@ void check_proc_info(Checker *c, ProcInfo pi) {
 		return;
 	}
 
+	if (pt->is_polymorphic && pt->is_poly_specialized) {
+		Entity *e = pi.decl->entity;
+		if ((e->flags & EntityFlag_Used) == 0) {
+			// NOTE(bill, 2019-08-31): It was never used, don't check
+			return;
+		}
+	}
+
 	bool bounds_check    = (pi.tags & ProcTag_bounds_check)    != 0;
 	bool no_bounds_check = (pi.tags & ProcTag_no_bounds_check) != 0;
 
diff --git a/src/checker.hpp b/src/checker.hpp
index 66b68c35c..c33514511 100644
--- a/src/checker.hpp
+++ b/src/checker.hpp
@@ -59,218 +59,8 @@ struct BuiltinProc {
 	BuiltinProcPkg pkg;
 };
 
-enum BuiltinProcId {
-	BuiltinProc_Invalid,
-
-	BuiltinProc_len,
-	BuiltinProc_cap,
-
-	BuiltinProc_size_of,
-	BuiltinProc_align_of,
-	BuiltinProc_offset_of,
-	BuiltinProc_type_of,
-	BuiltinProc_type_info_of,
-	BuiltinProc_typeid_of,
-
-	BuiltinProc_swizzle,
-
-	BuiltinProc_complex,
-	BuiltinProc_real,
-	BuiltinProc_imag,
-	BuiltinProc_conj,
-
-	BuiltinProc_expand_to_tuple,
-
-	BuiltinProc_min,
-	BuiltinProc_max,
-	BuiltinProc_abs,
-	BuiltinProc_clamp,
-
-	BuiltinProc_DIRECTIVE, // NOTE(bill): This is used for specialized hash-prefixed procedures
-
-	// "Intrinsics"
-	BuiltinProc_vector,
-
-	BuiltinProc_atomic_fence,
-	BuiltinProc_atomic_fence_acq,
-	BuiltinProc_atomic_fence_rel,
-	BuiltinProc_atomic_fence_acqrel,
-
-	BuiltinProc_atomic_store,
-	BuiltinProc_atomic_store_rel,
-	BuiltinProc_atomic_store_relaxed,
-	BuiltinProc_atomic_store_unordered,
-
-	BuiltinProc_atomic_load,
-	BuiltinProc_atomic_load_acq,
-	BuiltinProc_atomic_load_relaxed,
-	BuiltinProc_atomic_load_unordered,
-
-	BuiltinProc_atomic_add,
-	BuiltinProc_atomic_add_acq,
-	BuiltinProc_atomic_add_rel,
-	BuiltinProc_atomic_add_acqrel,
-	BuiltinProc_atomic_add_relaxed,
-	BuiltinProc_atomic_sub,
-	BuiltinProc_atomic_sub_acq,
-	BuiltinProc_atomic_sub_rel,
-	BuiltinProc_atomic_sub_acqrel,
-	BuiltinProc_atomic_sub_relaxed,
-	BuiltinProc_atomic_and,
-	BuiltinProc_atomic_and_acq,
-	BuiltinProc_atomic_and_rel,
-	BuiltinProc_atomic_and_acqrel,
-	BuiltinProc_atomic_and_relaxed,
-	BuiltinProc_atomic_nand,
-	BuiltinProc_atomic_nand_acq,
-	BuiltinProc_atomic_nand_rel,
-	BuiltinProc_atomic_nand_acqrel,
-	BuiltinProc_atomic_nand_relaxed,
-	BuiltinProc_atomic_or,
-	BuiltinProc_atomic_or_acq,
-	BuiltinProc_atomic_or_rel,
-	BuiltinProc_atomic_or_acqrel,
-	BuiltinProc_atomic_or_relaxed,
-	BuiltinProc_atomic_xor,
-	BuiltinProc_atomic_xor_acq,
-	BuiltinProc_atomic_xor_rel,
-	BuiltinProc_atomic_xor_acqrel,
-	BuiltinProc_atomic_xor_relaxed,
-
-	BuiltinProc_atomic_xchg,
-	BuiltinProc_atomic_xchg_acq,
-	BuiltinProc_atomic_xchg_rel,
-	BuiltinProc_atomic_xchg_acqrel,
-	BuiltinProc_atomic_xchg_relaxed,
-
-	BuiltinProc_atomic_cxchg,
-	BuiltinProc_atomic_cxchg_acq,
-	BuiltinProc_atomic_cxchg_rel,
-	BuiltinProc_atomic_cxchg_acqrel,
-	BuiltinProc_atomic_cxchg_relaxed,
-	BuiltinProc_atomic_cxchg_failrelaxed,
-	BuiltinProc_atomic_cxchg_failacq,
-	BuiltinProc_atomic_cxchg_acq_failrelaxed,
-	BuiltinProc_atomic_cxchg_acqrel_failrelaxed,
-
-	BuiltinProc_atomic_cxchgweak,
-	BuiltinProc_atomic_cxchgweak_acq,
-	BuiltinProc_atomic_cxchgweak_rel,
-	BuiltinProc_atomic_cxchgweak_acqrel,
-	BuiltinProc_atomic_cxchgweak_relaxed,
-	BuiltinProc_atomic_cxchgweak_failrelaxed,
-	BuiltinProc_atomic_cxchgweak_failacq,
-	BuiltinProc_atomic_cxchgweak_acq_failrelaxed,
-	BuiltinProc_atomic_cxchgweak_acqrel_failrelaxed,
-
-	BuiltinProc_COUNT,
-};
-gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
-	{STR_LIT(""),                 0, false, Expr_Stmt, BuiltinProcPkg_builtin},
-
-	{STR_LIT("len"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("cap"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
-
-	{STR_LIT("size_of"),          1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("align_of"),         1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("offset_of"),        2, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("type_of"),          1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("type_info_of"),     1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("typeid_of"),        1, false, Expr_Expr, BuiltinProcPkg_builtin},
-
-	{STR_LIT("swizzle"),          1, true,  Expr_Expr, BuiltinProcPkg_builtin},
-
-	{STR_LIT("complex"),          2, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("real"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("imag"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("conj"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
-
-	{STR_LIT("expand_to_tuple"),  1, false, Expr_Expr, BuiltinProcPkg_builtin},
-
-	{STR_LIT("min"),              1, true,  Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("max"),              1, true,  Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("abs"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
-	{STR_LIT("clamp"),            3, false, Expr_Expr, BuiltinProcPkg_builtin},
-
-	{STR_LIT(""),                 0, true,  Expr_Expr, BuiltinProcPkg_builtin}, // DIRECTIVE
-
-
-	// "Intrinsics"
-	{STR_LIT("vector"), 2, false, Expr_Expr, BuiltinProcPkg_intrinsics}, // Type
-
-
-	{STR_LIT("atomic_fence"),        0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_fence_acq"),    0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_fence_rel"),    0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_fence_acqrel"), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-
-	{STR_LIT("atomic_store"),           2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_store_rel"),       2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_store_relaxed"),   2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_store_unordered"), 2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
-
-	{STR_LIT("atomic_load"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_load_acq"),        1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_load_relaxed"),    1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_load_unordered"),  1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-
-	{STR_LIT("atomic_add"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_add_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_add_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_add_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_add_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_sub"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_sub_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_sub_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_sub_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_sub_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_and"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_and_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_and_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_and_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_and_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_nand"),            2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_nand_acq"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_nand_rel"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_nand_acqrel"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_nand_relaxed"),    2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_or"),              2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_or_acq"),          2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_or_rel"),          2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_or_acqrel"),       2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_or_relaxed"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xor"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xor_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xor_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xor_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xor_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-
-	{STR_LIT("atomic_xchg"),            2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xchg_acq"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xchg_rel"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xchg_acqrel"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_xchg_relaxed"),    2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-
-	{STR_LIT("atomic_cxchg"),                    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_acq"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_rel"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_acqrel"),             3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_relaxed"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_failrelaxed"),        3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_failacq"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_acq_failrelaxed"),    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchg_acqrel_failrelaxed"), 3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-
-	{STR_LIT("atomic_cxchgweak"),                    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_acq"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_rel"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_acqrel"),             3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_relaxed"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_failrelaxed"),        3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_failacq"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_acq_failrelaxed"),    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-	{STR_LIT("atomic_cxchgweak_acqrel_failrelaxed"), 3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
-};
+
+#include "checker_builtin_procs.hpp"
 
 
 // Operand is used as an intermediate value whilst checking
@@ -307,6 +97,7 @@ struct DeferredProcedure {
 struct AttributeContext {
 	bool    is_export;
 	bool    is_static;
+	bool    require_results;
 	String  link_name;
 	String  link_prefix;
 	isize   init_expr_list_count;
@@ -431,6 +222,7 @@ struct ForeignContext {
 typedef Array<Entity *> CheckerTypePath;
 typedef Array<Type *>   CheckerPolyPath;
 
+
 // CheckerInfo stores all the symbol information for a type-checked program
 struct CheckerInfo {
 	Map<ExprInfo>         untyped; // Key: Ast * | Expression -> ExprInfo
@@ -486,10 +278,14 @@ struct CheckerContext {
 	CheckerPolyPath *poly_path;
 	isize            poly_level; // TODO(bill): Actually handle correctly
 
+#define MAX_INLINE_FOR_DEPTH 1024ll
+	i64 inline_for_depth;
+
 	bool       in_enum_type;
 	bool       collect_delayed_decls;
 	bool       allow_polymorphic_types;
 	bool       no_polymorphic_errors;
+	bool       hide_polymorphic_errors;
 	bool       in_polymorphic_specialization;
 	Scope *    polymorphic_scope;
 };
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
new file mode 100644
index 000000000..50d27d715
--- /dev/null
+++ b/src/checker_builtin_procs.hpp
@@ -0,0 +1,320 @@
+// checker_builtin_procs.hpp
+
+enum BuiltinProcId {
+	BuiltinProc_Invalid,
+
+	BuiltinProc_len,
+	BuiltinProc_cap,
+
+	BuiltinProc_size_of,
+	BuiltinProc_align_of,
+	BuiltinProc_offset_of,
+	BuiltinProc_type_of,
+	BuiltinProc_type_info_of,
+	BuiltinProc_typeid_of,
+
+	BuiltinProc_swizzle,
+
+	BuiltinProc_complex,
+	BuiltinProc_quaternion,
+	BuiltinProc_real,
+	BuiltinProc_imag,
+	BuiltinProc_jmag,
+	BuiltinProc_kmag,
+	BuiltinProc_conj,
+
+	BuiltinProc_expand_to_tuple,
+
+	BuiltinProc_min,
+	BuiltinProc_max,
+	BuiltinProc_abs,
+	BuiltinProc_clamp,
+
+	BuiltinProc_DIRECTIVE, // NOTE(bill): This is used for specialized hash-prefixed procedures
+
+	// "Intrinsics"
+	BuiltinProc_vector,
+
+	BuiltinProc_atomic_fence,
+	BuiltinProc_atomic_fence_acq,
+	BuiltinProc_atomic_fence_rel,
+	BuiltinProc_atomic_fence_acqrel,
+
+	BuiltinProc_atomic_store,
+	BuiltinProc_atomic_store_rel,
+	BuiltinProc_atomic_store_relaxed,
+	BuiltinProc_atomic_store_unordered,
+
+	BuiltinProc_atomic_load,
+	BuiltinProc_atomic_load_acq,
+	BuiltinProc_atomic_load_relaxed,
+	BuiltinProc_atomic_load_unordered,
+
+	BuiltinProc_atomic_add,
+	BuiltinProc_atomic_add_acq,
+	BuiltinProc_atomic_add_rel,
+	BuiltinProc_atomic_add_acqrel,
+	BuiltinProc_atomic_add_relaxed,
+	BuiltinProc_atomic_sub,
+	BuiltinProc_atomic_sub_acq,
+	BuiltinProc_atomic_sub_rel,
+	BuiltinProc_atomic_sub_acqrel,
+	BuiltinProc_atomic_sub_relaxed,
+	BuiltinProc_atomic_and,
+	BuiltinProc_atomic_and_acq,
+	BuiltinProc_atomic_and_rel,
+	BuiltinProc_atomic_and_acqrel,
+	BuiltinProc_atomic_and_relaxed,
+	BuiltinProc_atomic_nand,
+	BuiltinProc_atomic_nand_acq,
+	BuiltinProc_atomic_nand_rel,
+	BuiltinProc_atomic_nand_acqrel,
+	BuiltinProc_atomic_nand_relaxed,
+	BuiltinProc_atomic_or,
+	BuiltinProc_atomic_or_acq,
+	BuiltinProc_atomic_or_rel,
+	BuiltinProc_atomic_or_acqrel,
+	BuiltinProc_atomic_or_relaxed,
+	BuiltinProc_atomic_xor,
+	BuiltinProc_atomic_xor_acq,
+	BuiltinProc_atomic_xor_rel,
+	BuiltinProc_atomic_xor_acqrel,
+	BuiltinProc_atomic_xor_relaxed,
+
+	BuiltinProc_atomic_xchg,
+	BuiltinProc_atomic_xchg_acq,
+	BuiltinProc_atomic_xchg_rel,
+	BuiltinProc_atomic_xchg_acqrel,
+	BuiltinProc_atomic_xchg_relaxed,
+
+	BuiltinProc_atomic_cxchg,
+	BuiltinProc_atomic_cxchg_acq,
+	BuiltinProc_atomic_cxchg_rel,
+	BuiltinProc_atomic_cxchg_acqrel,
+	BuiltinProc_atomic_cxchg_relaxed,
+	BuiltinProc_atomic_cxchg_failrelaxed,
+	BuiltinProc_atomic_cxchg_failacq,
+	BuiltinProc_atomic_cxchg_acq_failrelaxed,
+	BuiltinProc_atomic_cxchg_acqrel_failrelaxed,
+
+	BuiltinProc_atomic_cxchgweak,
+	BuiltinProc_atomic_cxchgweak_acq,
+	BuiltinProc_atomic_cxchgweak_rel,
+	BuiltinProc_atomic_cxchgweak_acqrel,
+	BuiltinProc_atomic_cxchgweak_relaxed,
+	BuiltinProc_atomic_cxchgweak_failrelaxed,
+	BuiltinProc_atomic_cxchgweak_failacq,
+	BuiltinProc_atomic_cxchgweak_acq_failrelaxed,
+	BuiltinProc_atomic_cxchgweak_acqrel_failrelaxed,
+
+
+	// Constant type tests
+BuiltinProc__type_begin,
+
+	BuiltinProc_type_base_type,
+	BuiltinProc_type_core_type,
+	BuiltinProc_type_elem_type,
+
+	BuiltinProc_type_is_boolean,
+	BuiltinProc_type_is_integer,
+	BuiltinProc_type_is_rune,
+	BuiltinProc_type_is_float,
+	BuiltinProc_type_is_complex,
+	BuiltinProc_type_is_quaternion,
+	BuiltinProc_type_is_string,
+	BuiltinProc_type_is_typeid,
+	BuiltinProc_type_is_any,
+
+	BuiltinProc_type_is_endian_little,
+	BuiltinProc_type_is_endian_big,
+	BuiltinProc_type_is_numeric,
+	BuiltinProc_type_is_ordered,
+	BuiltinProc_type_is_ordered_numeric,
+	BuiltinProc_type_is_indexable,
+	BuiltinProc_type_is_sliceable,
+	BuiltinProc_type_is_simple_compare, // easily compared using memcmp
+	BuiltinProc_type_is_dereferenceable,
+	BuiltinProc_type_is_valid_map_key,
+
+	BuiltinProc_type_is_named,
+	BuiltinProc_type_is_pointer,
+	BuiltinProc_type_is_opaque,
+	BuiltinProc_type_is_array,
+	BuiltinProc_type_is_slice,
+	BuiltinProc_type_is_dynamic_array,
+	BuiltinProc_type_is_map,
+	BuiltinProc_type_is_struct,
+	BuiltinProc_type_is_union,
+	BuiltinProc_type_is_enum,
+	BuiltinProc_type_is_proc,
+	BuiltinProc_type_is_bit_field,
+	BuiltinProc_type_is_bit_field_value,
+	BuiltinProc_type_is_bit_set,
+	BuiltinProc_type_is_simd_vector,
+
+	BuiltinProc_type_has_nil,
+
+	BuiltinProc_type_proc_parameter_count,
+	BuiltinProc_type_proc_return_count,
+
+BuiltinProc__type_end,
+
+	BuiltinProc_COUNT,
+};
+gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
+	{STR_LIT(""),                 0, false, Expr_Stmt, BuiltinProcPkg_builtin},
+
+	{STR_LIT("len"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("cap"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
+
+	{STR_LIT("size_of"),          1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("align_of"),         1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("offset_of"),        2, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("type_of"),          1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("type_info_of"),     1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("typeid_of"),        1, false, Expr_Expr, BuiltinProcPkg_builtin},
+
+	{STR_LIT("swizzle"),          1, true,  Expr_Expr, BuiltinProcPkg_builtin},
+
+	{STR_LIT("complex"),          2, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("quaternion"),       4, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("real"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("imag"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("jmag"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("kmag"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("conj"),             1, false, Expr_Expr, BuiltinProcPkg_builtin},
+
+	{STR_LIT("expand_to_tuple"),  1, false, Expr_Expr, BuiltinProcPkg_builtin},
+
+	{STR_LIT("min"),              1, true,  Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("max"),              1, true,  Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("abs"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("clamp"),            3, false, Expr_Expr, BuiltinProcPkg_builtin},
+
+	{STR_LIT(""),                 0, true,  Expr_Expr, BuiltinProcPkg_builtin}, // DIRECTIVE
+
+
+	// "Intrinsics"
+	{STR_LIT("vector"), 2, false, Expr_Expr, BuiltinProcPkg_intrinsics}, // Type
+
+	{STR_LIT("atomic_fence"),        0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_fence_acq"),    0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_fence_rel"),    0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_fence_acqrel"), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("atomic_store"),           2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_store_rel"),       2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_store_relaxed"),   2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_store_unordered"), 2, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("atomic_load"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_load_acq"),        1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_load_relaxed"),    1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_load_unordered"),  1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("atomic_add"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_add_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_add_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_add_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_add_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_sub"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_sub_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_sub_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_sub_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_sub_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_and"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_and_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_and_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_and_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_and_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_nand"),            2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_nand_acq"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_nand_rel"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_nand_acqrel"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_nand_relaxed"),    2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_or"),              2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_or_acq"),          2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_or_rel"),          2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_or_acqrel"),       2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_or_relaxed"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xor"),             2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xor_acq"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xor_rel"),         2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xor_acqrel"),      2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xor_relaxed"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("atomic_xchg"),            2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xchg_acq"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xchg_rel"),        2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xchg_acqrel"),     2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_xchg_relaxed"),    2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("atomic_cxchg"),                    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_acq"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_rel"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_acqrel"),             3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_relaxed"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_failrelaxed"),        3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_failacq"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_acq_failrelaxed"),    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchg_acqrel_failrelaxed"), 3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("atomic_cxchgweak"),                    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_acq"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_rel"),                3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_acqrel"),             3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_relaxed"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_failrelaxed"),        3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_failacq"),            3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_acq_failrelaxed"),    3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("atomic_cxchgweak_acqrel_failrelaxed"), 3, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+
+	{STR_LIT(""), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_base_type"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_core_type"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_elem_type"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("type_is_boolean"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_integer"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_rune"),              1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_float"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_complex"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_quaternion"),        1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_string"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_typeid"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_any"),               1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("type_is_endian_little"),     1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_endian_big"),        1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_numeric"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_ordered"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_ordered_numeric"),   1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_indexable"),         1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_sliceable"),         1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_simple_compare"),    1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_dereferenceable"),   1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_valid_map_key"),     1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("type_is_named"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_pointer"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_opaque"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_array"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_slice"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_dynamic_array"),     1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_map"),               1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_struct"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_union"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_enum"),              1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_proc"),              1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_bit_field"),         1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_bit_field_value"),   1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_bit_set"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_simd_vector"),       1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("type_has_nil"),              1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("type_proc_parameter_count"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_proc_return_count"),    1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT(""), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+};
diff --git a/src/common.cpp b/src/common.cpp
index 8085e895c..b034ad720 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -10,13 +10,11 @@
 #define GB_IMPLEMENTATION
 #include "gb/gb.h"
 
-
 #include <wchar.h>
 #include <stdio.h>
 
 #include <math.h>
 
-
 template <typename U, typename V>
 gb_inline U bit_cast(V &v) { return reinterpret_cast<U &>(v); }
 
@@ -145,6 +143,9 @@ GB_ALLOCATOR_PROC(heap_allocator_proc) {
 
 #define for_array(index_, array_) for (isize index_ = 0; index_ < (array_).count; index_++)
 
+#include "range_cache.cpp"
+
+
 
 u64 fnv64a(void const *data, isize len) {
 	u8 const *bytes = cast(u8 const *)data;
@@ -331,7 +332,7 @@ void mul_overflow_u64(u64 x, u64 y, u64 *lo, u64 *hi) {
 #include "ptr_set.cpp"
 #include "string_set.cpp"
 #include "priority_queue.cpp"
-
+#include "thread_pool.cpp"
 
 
 gb_global String global_module_path = {0};
@@ -873,7 +874,6 @@ ReadDirectoryError read_directory(String path, Array<FileInfo> *fi) {
 		info.size = size;
 		info.is_dir = (file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 		array_add(fi, info);
-
 	} while (FindNextFileW(find_file, &file_data));
 
 	if (fi->count == 0) {
diff --git a/src/entity.cpp b/src/entity.cpp
index 3318eac24..bbea68e8b 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -48,7 +48,8 @@ enum EntityFlag {
 	EntityFlag_NotExported   = 1<<14,
 
 	EntityFlag_Static        = 1<<16,
-	// EntityFlag_Reference     = 1<<17,
+
+	EntityFlag_ImplicitReference = 1<<17, // NOTE(bill): equivalent to `const &` in C++
 
 	EntityFlag_CVarArg       = 1<<20,
 	EntityFlag_AutoCast      = 1<<21,
@@ -183,10 +184,11 @@ bool is_entity_exported(Entity *e, bool allow_builtin = false) {
 	}
 
 	String name = e->token.string;
-	if (name.len == 0) {
-		return false;
+	switch (name.len) {
+	case 0: return false;
+	case 1: return name[0] != '_';
 	}
-	return name[0] != '_';
+	return true;
 }
 
 bool entity_has_deferred_procedure(Entity *e) {
@@ -219,12 +221,13 @@ Entity *alloc_entity_variable(Scope *scope, Token token, Type *type, bool is_imm
 	return entity;
 }
 
-Entity *alloc_entity_using_variable(Entity *parent, Token token, Type *type) {
+Entity *alloc_entity_using_variable(Entity *parent, Token token, Type *type, Ast *using_expr) {
 	GB_ASSERT(parent != nullptr);
 	token.pos = parent->token.pos;
 	Entity *entity = alloc_entity(Entity_Variable, parent->scope, token, type);
 	entity->using_parent = parent;
 	entity->parent_proc_decl = parent->parent_proc_decl;
+	entity->using_expr = using_expr;
 	entity->flags |= EntityFlag_Using;
 	entity->flags |= EntityFlag_Used;
 	entity->state = EntityState_Resolved;
diff --git a/src/exact_value.cpp b/src/exact_value.cpp
index 428690291..42b22c8ef 100644
--- a/src/exact_value.cpp
+++ b/src/exact_value.cpp
@@ -12,6 +12,19 @@ bool are_types_identical(Type *x, Type *y);
 struct Complex128 {
 	f64 real, imag;
 };
+struct Quaternion256 {
+	f64 imag, jmag, kmag, real;
+};
+
+Quaternion256 quaternion256_inverse(Quaternion256 x) {
+	f64 invmag2 = 1.0 / (x.real*x.real + x.imag*x.imag + x.jmag*x.jmag + x.kmag*x.kmag);
+	x.real = +x.real * invmag2;
+	x.imag = -x.imag * invmag2;
+	x.jmag = -x.jmag * invmag2;
+	x.kmag = -x.kmag * invmag2;
+	return x;
+}
+
 
 enum ExactValueKind {
 	ExactValue_Invalid,
@@ -21,9 +34,11 @@ enum ExactValueKind {
 	ExactValue_Integer,
 	ExactValue_Float,
 	ExactValue_Complex,
+	ExactValue_Quaternion,
 	ExactValue_Pointer,
 	ExactValue_Compound,  // TODO(bill): Is this good enough?
 	ExactValue_Procedure, // TODO(bill): Is this good enough?
+	ExactValue_Typeid,
 
 	ExactValue_Count,
 };
@@ -37,8 +52,10 @@ struct ExactValue {
 		f64           value_float;
 		i64           value_pointer;
 		Complex128    value_complex;
+		Quaternion256 value_quaternion;
 		Ast *         value_compound;
 		Ast *         value_procedure;
+		Type *        value_typeid;
 	};
 };
 
@@ -53,25 +70,22 @@ HashKey hash_exact_value(ExactValue v) {
 		return hash_integer(u64(v.value_bool));
 	case ExactValue_String:
 		return hash_string(v.value_string);
-	case ExactValue_Integer: {
-		u64 *d = big_int_ptr(&v.value_integer);
-		u64 x = 0;
-		for (i32 i = 0; i < v.value_integer.len; i++) {
-			x |= d[i];
-		}
-		return hash_integer(x);
-	}
+	case ExactValue_Integer:
+		return hashing_proc(big_int_ptr(&v.value_integer), v.value_integer.len * gb_size_of(u64));
 	case ExactValue_Float:
 		return hash_f64(v.value_float);
 	case ExactValue_Pointer:
 		return hash_integer(v.value_pointer);
 	case ExactValue_Complex:
 		return hashing_proc(&v.value_complex, gb_size_of(Complex128));
-
+	case ExactValue_Quaternion:
+		return hashing_proc(&v.value_quaternion, gb_size_of(Quaternion256));
 	case ExactValue_Compound:
 		return hash_pointer(v.value_compound);
 	case ExactValue_Procedure:
 		return hash_pointer(v.value_procedure);
+	case ExactValue_Typeid:
+		return hash_pointer(v.value_typeid);
 	}
 	return hashing_proc(&v, gb_size_of(ExactValue));
 
@@ -122,6 +136,15 @@ ExactValue exact_value_complex(f64 real, f64 imag) {
 	return result;
 }
 
+ExactValue exact_value_quaternion(f64 real, f64 imag, f64 jmag, f64 kmag) {
+	ExactValue result = {ExactValue_Quaternion};
+	result.value_quaternion.real = real;
+	result.value_quaternion.imag = imag;
+	result.value_quaternion.jmag = jmag;
+	result.value_quaternion.kmag = kmag;
+	return result;
+}
+
 ExactValue exact_value_pointer(i64 ptr) {
 	ExactValue result = {ExactValue_Pointer};
 	result.value_pointer = ptr;
@@ -135,6 +158,13 @@ ExactValue exact_value_procedure(Ast *node) {
 }
 
 
+ExactValue exact_value_typeid(Type *type) {
+	ExactValue result = {ExactValue_Typeid};
+	result.value_typeid = type;
+	return result;
+}
+
+
 ExactValue exact_value_integer_from_string(String const &string) {
 	ExactValue result = {ExactValue_Integer};
 	big_int_from_string(&result.value_integer, string);
@@ -259,14 +289,16 @@ ExactValue exact_value_from_basic_literal(Token token) {
 		str.len--; // Ignore the 'i|j|k'
 		f64 imag = float_from_string(str);
 
-		if (last_rune == 'i') {
-			return exact_value_complex(0, imag);
+		switch (last_rune) {
+		case 'i': return exact_value_complex(0, imag);
+		case 'j': return exact_value_quaternion(0, 0, imag, 0);
+		case 'k': return exact_value_quaternion(0, 0, 0, imag);
+		default: GB_PANIC("Invalid imaginary basic literal");
 		}
 	}
 	case Token_Rune: {
 		Rune r = GB_RUNE_INVALID;
 		gb_utf8_decode(token.string.text, token.string.len, &r);
-		// gb_printf("%.*s rune: %d\n", LIT(token.string), r);
 		return exact_value_i64(r);
 	}
 	default:
@@ -324,11 +356,26 @@ ExactValue exact_value_to_complex(ExactValue v) {
 		return exact_value_complex(v.value_float, 0);
 	case ExactValue_Complex:
 		return v;
+	// case ExactValue_Quaternion:
+		// return exact_value_complex(v.value_quaternion.real, v.value_quaternion.imag);
+	}
+	ExactValue r = {ExactValue_Invalid};
+	return r;
+}
+ExactValue exact_value_to_quaternion(ExactValue v) {
+	switch (v.kind) {
+	case ExactValue_Integer:
+		return exact_value_quaternion(big_int_to_f64(&v.value_integer), 0, 0, 0);
+	case ExactValue_Float:
+		return exact_value_quaternion(v.value_float, 0, 0, 0);
+	case ExactValue_Complex:
+		return exact_value_quaternion(v.value_complex.real, v.value_complex.imag, 0, 0);
+	case ExactValue_Quaternion:
+		return v;
 	}
 	ExactValue r = {ExactValue_Invalid};
 	return r;
 }
-
 
 ExactValue exact_value_real(ExactValue v) {
 	switch (v.kind) {
@@ -337,6 +384,8 @@ ExactValue exact_value_real(ExactValue v) {
 		return v;
 	case ExactValue_Complex:
 		return exact_value_float(v.value_complex.real);
+	case ExactValue_Quaternion:
+		return exact_value_float(v.value_quaternion.real);
 	}
 	ExactValue r = {ExactValue_Invalid};
 	return r;
@@ -349,6 +398,34 @@ ExactValue exact_value_imag(ExactValue v) {
 		return exact_value_i64(0);
 	case ExactValue_Complex:
 		return exact_value_float(v.value_complex.imag);
+	case ExactValue_Quaternion:
+		return exact_value_float(v.value_quaternion.imag);
+	}
+	ExactValue r = {ExactValue_Invalid};
+	return r;
+}
+
+ExactValue exact_value_jmag(ExactValue v) {
+	switch (v.kind) {
+	case ExactValue_Integer:
+	case ExactValue_Float:
+	case ExactValue_Complex:
+		return exact_value_i64(0);
+	case ExactValue_Quaternion:
+		return exact_value_float(v.value_quaternion.jmag);
+	}
+	ExactValue r = {ExactValue_Invalid};
+	return r;
+}
+
+ExactValue exact_value_kmag(ExactValue v) {
+	switch (v.kind) {
+	case ExactValue_Integer:
+	case ExactValue_Float:
+	case ExactValue_Complex:
+		return exact_value_i64(0);
+	case ExactValue_Quaternion:
+		return exact_value_float(v.value_quaternion.kmag);
 	}
 	ExactValue r = {ExactValue_Invalid};
 	return r;
@@ -367,6 +444,32 @@ ExactValue exact_value_make_imag(ExactValue v) {
 	return r;
 }
 
+ExactValue exact_value_make_jmag(ExactValue v) {
+	switch (v.kind) {
+	case ExactValue_Integer:
+		return exact_value_quaternion(0, 0, exact_value_to_float(v).value_float, 0);
+	case ExactValue_Float:
+		return exact_value_quaternion(0, 0, v.value_float, 0);
+	default:
+		GB_PANIC("Expected an integer or float type for 'exact_value_make_imag'");
+	}
+	ExactValue r = {ExactValue_Invalid};
+	return r;
+}
+
+ExactValue exact_value_make_kmag(ExactValue v) {
+	switch (v.kind) {
+	case ExactValue_Integer:
+		return exact_value_quaternion(0, 0, 0, exact_value_to_float(v).value_float);
+	case ExactValue_Float:
+		return exact_value_quaternion(0, 0, 0, v.value_float);
+	default:
+		GB_PANIC("Expected an integer or float type for 'exact_value_make_imag'");
+	}
+	ExactValue r = {ExactValue_Invalid};
+	return r;
+}
+
 i64 exact_value_to_i64(ExactValue v) {
 	v = exact_value_to_integer(v);
 	if (v.kind == ExactValue_Integer) {
@@ -395,6 +498,7 @@ ExactValue exact_unary_operator_value(TokenKind op, ExactValue v, i32 precision,
 		case ExactValue_Integer:
 		case ExactValue_Float:
 		case ExactValue_Complex:
+		case ExactValue_Quaternion:
 			return v;
 		}
 		break;
@@ -419,6 +523,13 @@ ExactValue exact_unary_operator_value(TokenKind op, ExactValue v, i32 precision,
 			f64 imag = v.value_complex.imag;
 			return exact_value_complex(-real, -imag);
 		}
+		case ExactValue_Quaternion: {
+			f64 real = v.value_quaternion.real;
+			f64 imag = v.value_quaternion.imag;
+			f64 jmag = v.value_quaternion.jmag;
+			f64 kmag = v.value_quaternion.kmag;
+			return exact_value_quaternion(-real, -imag, -jmag, -kmag);
+		}
 		}
 		break;
 	}
@@ -469,8 +580,10 @@ i32 exact_value_order(ExactValue const &v) {
 		return 3;
 	case ExactValue_Complex:
 		return 4;
-	case ExactValue_Pointer:
+	case ExactValue_Quaternion:
 		return 5;
+	case ExactValue_Pointer:
+		return 6;
 
 	default:
 		GB_PANIC("How'd you get here? Invalid Value.kind");
@@ -491,7 +604,7 @@ void match_exact_values(ExactValue *x, ExactValue *y) {
 
 	case ExactValue_Bool:
 	case ExactValue_String:
-	case ExactValue_Complex:
+	case ExactValue_Quaternion:
 		return;
 
 	case ExactValue_Integer:
@@ -505,6 +618,9 @@ void match_exact_values(ExactValue *x, ExactValue *y) {
 		case ExactValue_Complex:
 			*x = exact_value_complex(big_int_to_f64(&x->value_integer), 0);
 			return;
+		case ExactValue_Quaternion:
+			*x = exact_value_quaternion(big_int_to_f64(&x->value_integer), 0, 0, 0);
+			return;
 		}
 		break;
 
@@ -515,6 +631,17 @@ void match_exact_values(ExactValue *x, ExactValue *y) {
 		case ExactValue_Complex:
 			*x = exact_value_to_complex(*x);
 			return;
+		case ExactValue_Quaternion:
+			*x = exact_value_to_quaternion(*x);
+			return;
+		}
+		break;
+
+	case ExactValue_Complex:
+		switch (y->kind) {
+		case ExactValue_Quaternion:
+			*x = exact_value_to_quaternion(*x);
+			return;
 		}
 		break;
 	}
@@ -612,6 +739,56 @@ ExactValue exact_binary_operator_value(TokenKind op, ExactValue x, ExactValue y)
 		break;
 	}
 
+	case ExactValue_Quaternion: {
+		y = exact_value_to_quaternion(y);
+		f64 xr = x.value_quaternion.real;
+		f64 xi = x.value_quaternion.imag;
+		f64 xj = x.value_quaternion.jmag;
+		f64 xk = x.value_quaternion.kmag;
+		f64 yr = y.value_quaternion.real;
+		f64 yi = y.value_quaternion.imag;
+		f64 yj = y.value_quaternion.jmag;
+		f64 yk = y.value_quaternion.kmag;
+
+
+		f64 real = 0;
+		f64 imag = 0;
+		f64 jmag = 0;
+		f64 kmag = 0;
+
+		switch (op) {
+		case Token_Add:
+			real = xr + yr;
+			imag = xi + yi;
+			jmag = xj + yj;
+			kmag = xk + yk;
+			break;
+		case Token_Sub:
+			real = xr - yr;
+			imag = xi - yi;
+			jmag = xj - yj;
+			kmag = xk - yk;
+			break;
+		case Token_Mul:
+			imag = xr * yi + xi * yr + xj * yk - xk * yj;
+			jmag = xr * yj - xi * yk + xj * yr + xk * yi;
+			kmag = xr * yk + xi * yj - xj * yi + xk * yr;
+			real = xr * yr - xi * yi - xj * yj - xk * yk;
+			break;
+		case Token_Quo: {
+			f64 invmag2 = 1.0 / (yr*yr + yi*yi + yj*yj + yk*yk);
+			imag = (xr * -yi + xi * +yr + xj * -yk - xk * -yj) * invmag2;
+			jmag = (xr * -yj - xi * -yk + xj * +yr + xk * -yi) * invmag2;
+			kmag = (xr * -yk + xi * -yj - xj * -yi + xk * +yr) * invmag2;
+			real = (xr * +yr - xi * -yi - xj * -yj - xk * -yk) * invmag2;
+			break;
+		}
+		default: goto error;
+		}
+		return exact_value_quaternion(real, imag, jmag, kmag);
+		break;
+	}
+
 	case ExactValue_String: {
 		if (op != Token_Add) goto error;
 
@@ -647,6 +824,10 @@ gb_inline ExactValue exact_value_shift(TokenKind op, ExactValue const &x, ExactV
 	return exact_binary_operator_value(op, x, y);
 }
 
+gb_inline ExactValue exact_value_increment_one(ExactValue const &x) {
+	return exact_binary_operator_value(Token_Add, x, exact_value_i64(1));
+}
+
 
 i32 cmp_f64(f64 a, f64 b) {
 	return (a > b) - (a < b);
@@ -719,8 +900,61 @@ bool compare_exact_values(TokenKind op, ExactValue x, ExactValue y) {
 		}
 		break;
 	}
+
+	case ExactValue_Typeid:
+		switch (op) {
+		case Token_CmpEq: return are_types_identical(x.value_typeid, y.value_typeid);
+		case Token_NotEq: return !are_types_identical(x.value_typeid, y.value_typeid);
+		}
+		break;
 	}
 
 	GB_PANIC("Invalid comparison");
 	return false;
 }
+
+
+gbString write_exact_value_to_string(gbString str, ExactValue const &v, isize string_limit=36) {
+	switch (v.kind) {
+	case ExactValue_Invalid:
+		return str;
+	case ExactValue_Bool:
+		return gb_string_appendc(str, v.value_bool ? "true" : "false");
+	case ExactValue_String: {
+		String s = quote_to_ascii(heap_allocator(), v.value_string);
+		string_limit = gb_max(string_limit, 36);
+		if (s.len <= string_limit) {
+			str = gb_string_append_length(str, s.text, s.len);
+		} else {
+			isize n = string_limit/5;
+			str = gb_string_append_length(str, s.text, n);
+			str = gb_string_append_fmt(str, "\"..%lld chars..\"", s.len-(2*n));
+			str = gb_string_append_length(str, s.text+s.len-n, n);
+		}
+		gb_free(heap_allocator(), s.text);
+		return str;
+	}
+	case ExactValue_Integer: {
+		String s = big_int_to_string(heap_allocator(), &v.value_integer);
+		str = gb_string_append_length(str, s.text, s.len);
+		gb_free(heap_allocator(), s.text);
+		return str;
+	}
+	case ExactValue_Float:
+		return gb_string_append_fmt(str, "%f", v.value_float);
+	case ExactValue_Complex:
+		return gb_string_append_fmt(str, "%f+%fi", v.value_complex.real, v.value_complex.imag);
+
+	case ExactValue_Pointer:
+		return str;
+	case ExactValue_Compound:
+		return str;
+	case ExactValue_Procedure:
+		return str;
+	}
+	return str;
+};
+
+gbString exact_value_to_string(ExactValue const &v, isize string_limit=36) {
+	return write_exact_value_to_string(gb_string_make(heap_allocator(), ""), v, string_limit);
+}
diff --git a/src/gb/gb.h b/src/gb/gb.h
index adeb554b2..60303729f 100644
--- a/src/gb/gb.h
+++ b/src/gb/gb.h
@@ -918,7 +918,7 @@ GB_DEF void gb_lfence      (void);
 
 
 #if defined(GB_SYSTEM_WINDOWS)
-typedef struct gbSemaphore { void *win32_handle; }     gbSemaphore;
+typedef struct gbSemaphore { void *win32_handle;}      gbSemaphore;
 #elif defined(GB_SYSTEM_OSX)
 typedef struct gbSemaphore { semaphore_t osx_handle; } gbSemaphore;
 #elif defined(GB_SYSTEM_UNIX)
@@ -930,7 +930,7 @@ typedef struct gbSemaphore { sem_t unix_handle; }      gbSemaphore;
 GB_DEF void gb_semaphore_init   (gbSemaphore *s);
 GB_DEF void gb_semaphore_destroy(gbSemaphore *s);
 GB_DEF void gb_semaphore_post   (gbSemaphore *s, i32 count);
-GB_DEF void gb_semaphore_release(gbSemaphore *s); // NOTE(bill): gb_semaphore_post(s, 1)
+GB_DEF void gb_semaphore_release(gbSemaphore *s);
 GB_DEF void gb_semaphore_wait   (gbSemaphore *s);
 
 
@@ -975,10 +975,10 @@ typedef struct gbThread {
 	pthread_t     posix_handle;
 #endif
 
-	gbThreadProc *proc;
-	void *        user_data;
-	isize         user_index;
-	isize         return_value;
+	gbThreadProc * proc;
+	void *         user_data;
+	isize          user_index;
+	isize volatile return_value;
 
 	gbSemaphore   semaphore;
 	isize         stack_size;
@@ -4588,10 +4588,18 @@ gb_inline void gb_lfence(void) {
 gb_inline void gb_semaphore_release(gbSemaphore *s) { gb_semaphore_post(s, 1); }
 
 #if defined(GB_SYSTEM_WINDOWS)
-	gb_inline void gb_semaphore_init   (gbSemaphore *s)            { s->win32_handle = CreateSemaphoreA(NULL, 0, I32_MAX, NULL); }
-	gb_inline void gb_semaphore_destroy(gbSemaphore *s)            { CloseHandle(s->win32_handle); }
-	gb_inline void gb_semaphore_post   (gbSemaphore *s, i32 count) { ReleaseSemaphore(s->win32_handle, count, NULL); }
-	gb_inline void gb_semaphore_wait   (gbSemaphore *s)            { WaitForSingleObject(s->win32_handle, INFINITE); }
+	gb_inline void gb_semaphore_init(gbSemaphore *s) {
+		s->win32_handle = CreateSemaphoreA(NULL, 0, I32_MAX, NULL);
+	}
+	gb_inline void gb_semaphore_destroy(gbSemaphore *s) {
+		CloseHandle(s->win32_handle);
+	}
+	gb_inline void gb_semaphore_post(gbSemaphore *s, i32 count) {
+		ReleaseSemaphore(s->win32_handle, count, NULL);
+	}
+	gb_inline void gb_semaphore_wait(gbSemaphore *s) {
+		WaitForSingleObjectEx(s->win32_handle, INFINITE, FALSE);
+	}
 
 #elif defined(GB_SYSTEM_OSX)
 	gb_inline void gb_semaphore_init   (gbSemaphore *s)            { semaphore_create(mach_task_self(), &s->osx_handle, SYNC_POLICY_FIFO, 0); }
@@ -8975,7 +8983,7 @@ gb_inline void gb_exit(u32 code) { exit(code); }
 
 gb_inline void gb_yield(void) {
 #if defined(GB_SYSTEM_WINDOWS)
-	Sleep(0);
+	YieldProcessor();
 #else
 	sched_yield();
 #endif
diff --git a/src/ir.cpp b/src/ir.cpp
index 82f9fa755..e7317a960 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -147,6 +147,7 @@ struct irProcedure {
 
 	Array<irContextData>  context_stack;
 
+	i32      parameter_count;
 
 	irValue *return_ptr_hint_value;
 	Ast *    return_ptr_hint_ast;
@@ -174,6 +175,7 @@ gbAllocator ir_allocator(void) {
 #define IR_TYPE_INFO_NAMES_NAME      "__$type_info_names_data"
 #define IR_TYPE_INFO_OFFSETS_NAME    "__$type_info_offsets_data"
 #define IR_TYPE_INFO_USINGS_NAME     "__$type_info_usings_data"
+#define IR_TYPE_INFO_TAGS_NAME       "__$type_info_tags_data"
 
 
 #define IR_INSTR_KINDS \
@@ -424,6 +426,7 @@ enum irParamPasskind {
 	irParamPass_Integer,  // Pass as an integer of the same size
 	irParamPass_ConstRef, // Pass as a pointer but the value is immutable
 	irParamPass_BitCast,  // Pass by value and bit cast to the correct type
+	irParamPass_Tuple,    // Pass across multiple parameters (System V AMD64, up to 2)
 };
 
 struct irValueParam {
@@ -432,6 +435,7 @@ struct irValueParam {
 	Entity *         entity;
 	Type *           type;
 	Type *           original_type;
+	i32              index;
 	Array<irValue *> referrers;
 };
 
@@ -913,15 +917,18 @@ irValue *ir_value_global(Entity *e, irValue *value) {
 	if (value) value->uses += 1;
 	return v;
 }
-irValue *ir_value_param(irProcedure *parent, Entity *e, Type *abi_type) {
+irValue *ir_value_param(irProcedure *parent, Entity *e, Type *abi_type, i32 index) {
 	irValue *v = ir_alloc_value(irValue_Param);
 	v->Param.kind          = irParamPass_Value;
 	v->Param.parent        = parent;
-	v->Param.entity        = e;
-	v->Param.original_type = e->type;
+	if (e != nullptr) {
+		v->Param.entity        = e;
+		v->Param.original_type = e->type;
+	}
 	v->Param.type          = abi_type;
+	v->Param.index         = index;
 
-	if (abi_type != e->type) {
+	if (e != nullptr && abi_type != e->type) {
 		if (is_type_pointer(abi_type)) {
 			GB_ASSERT(e->kind == Entity_Variable);
 			v->Param.kind = irParamPass_Pointer;
@@ -934,8 +941,12 @@ irValue *ir_value_param(irProcedure *parent, Entity *e, Type *abi_type) {
 			v->Param.kind = irParamPass_Value;
 		} else if (is_type_simd_vector(abi_type)) {
 			v->Param.kind = irParamPass_BitCast;
+		} else if (is_type_float(abi_type)) {
+			v->Param.kind = irParamPass_BitCast;
+		} else if (is_type_tuple(abi_type)) {
+			v->Param.kind = irParamPass_Tuple;
 		} else {
-			GB_PANIC("Invalid abi type pass kind");
+			GB_PANIC("Invalid abi type pass kind %s", type_to_string(abi_type));
 		}
 	}
 	array_init(&v->Param.referrers, heap_allocator()); // TODO(bill): Replace heap allocator here
@@ -1428,7 +1439,7 @@ irValue *ir_value_procedure(irModule *m, Entity *entity, Type *type, Ast *type_e
 
 	Type *t = base_type(type);
 	GB_ASSERT(is_type_proc(t));
-	array_init(&v->Proc.params, ir_allocator(), 0, t->Proc.param_count);
+	array_init(&v->Proc.params, heap_allocator(), 0, t->Proc.param_count);
 
 	return v;
 }
@@ -1498,7 +1509,9 @@ void ir_start_block(irProcedure *proc, irBlock *block) {
 }
 
 
-
+irValue *ir_emit_transmute(irProcedure *proc, irValue *value, Type *t);
+irValue *ir_address_from_load_or_generate_local(irProcedure *proc, irValue *val);
+irValue *ir_emit_struct_ep(irProcedure *proc, irValue *s, i32 index);
 
 
 
@@ -1539,6 +1552,7 @@ irValue *ir_add_module_constant(irModule *m, Type *type, ExactValue value) {
 			if (count == 0) {
 				return ir_value_nil(type);
 			}
+			count = gb_max(cl->max_count, count);
 			Type *elem = base_type(type)->Slice.elem;
 			Type *t = alloc_type_array(elem, count);
 			irValue *backing_array = ir_add_module_constant(m, t, value);
@@ -1712,9 +1726,12 @@ irValue *ir_add_global_generated(irModule *m, Type *type, irValue *value) {
 
 
 irValue *ir_add_param(irProcedure *proc, Entity *e, Ast *expr, Type *abi_type, i32 index) {
-	irValue *v = ir_value_param(proc, e, abi_type);
+	irValue *v = ir_value_param(proc, e, abi_type, index);
+	array_add(&proc->params, v);
 	irValueParam *p = &v->Param;
 
+	irValue *res = nullptr;
+
 	ir_push_debug_location(proc->module, e ? e->identifier : nullptr, proc->debug_scope, e);
 	defer (ir_pop_debug_location(proc->module));
 
@@ -1749,6 +1766,24 @@ irValue *ir_add_param(irProcedure *proc, Entity *e, Ast *expr, Type *abi_type, i
 		ir_emit_store(proc, l, x);
 		return x;
 	}
+	case irParamPass_Tuple: {
+		irValue *l = ir_add_local(proc, e, expr, true, index);
+		Type *st = struct_type_from_systemv_distribute_struct_fields(abi_type);
+		irValue *ptr = ir_emit_bitcast(proc, l, alloc_type_pointer(st));
+		if (abi_type->Tuple.variables.count > 0) {
+			array_pop(&proc->params);
+		}
+		for_array(i, abi_type->Tuple.variables) {
+			Type *t = abi_type->Tuple.variables[i]->type;
+
+			irValue *elem = ir_value_param(proc, nullptr, t, index+cast(i32)i);
+			array_add(&proc->params, elem);
+
+			irValue *dst = ir_emit_struct_ep(proc, ptr, cast(i32)i);
+			ir_emit_store(proc, dst, elem);
+		}
+		return ir_emit_load(proc, l);
+	}
 
 	}
 
@@ -1872,10 +1907,12 @@ irDebugEncoding ir_debug_encoding_for_basic(BasicKind kind) {
 	case Basic_string:
 	case Basic_any:
 	case Basic_rawptr:
+	case Basic_quaternion128:
+	case Basic_quaternion256:
 		break; // not a "DIBasicType"
 	}
 
-	GB_PANIC("Unreachable");
+	GB_PANIC("Unreachable %d", kind);
 	return irDebugBasicEncoding_Invalid;
 }
 
@@ -2221,27 +2258,11 @@ irDebugInfo *ir_add_debug_info_type_complex(irModule *module, Type *type) {
 	di->CompositeType.tag = irDebugBasicEncoding_structure_type;
 	di->CompositeType.size = ir_debug_size_bits(type);
 
-	Type *field_type = nullptr;
-	if (type->Basic.kind == Basic_complex64) {
-		field_type = t_f32;
-	} else if (type->Basic.kind == Basic_complex128) {
-		field_type = t_f64;
-	} else {
-		GB_PANIC("Unreachable");
-	}
+	Type *field_type = base_complex_elem_type(type);
 
-	// Field "real"
-	irDebugInfo *real_di = ir_add_debug_info_field_internal(module, str_lit("real"), field_type,
-															0,
-															nullptr,
-															di);
+	irDebugInfo *real_di = ir_add_debug_info_field_internal(module, str_lit("real"), field_type, 0*cast(i32)type_size_of(field_type), nullptr, di);
+	irDebugInfo *imag_di = ir_add_debug_info_field_internal(module, str_lit("imag"), field_type, 1*cast(i32)type_size_of(field_type), nullptr, di);
 	map_set(&module->debug_info, hash_pointer(real_di), real_di);
-
-	// Field "imag"
-	irDebugInfo *imag_di = ir_add_debug_info_field_internal(module, str_lit("imag"), field_type,
-															real_di->DerivedType.size,
-															nullptr,
-															di);
 	map_set(&module->debug_info, hash_pointer(imag_di), imag_di);
 
 	irDebugInfo *elements_di = ir_add_debug_info_array(module, 0, 2);
@@ -2253,6 +2274,40 @@ irDebugInfo *ir_add_debug_info_type_complex(irModule *module, Type *type) {
 	return di;
 }
 
+irDebugInfo *ir_add_debug_info_type_quaternion(irModule *module, Type *type) {
+	GB_ASSERT(type->kind == Type_Basic && is_type_quaternion(type));
+
+	irDebugInfo *di = ir_alloc_debug_info(irDebugInfo_CompositeType);
+	map_set(&module->debug_info, hash_type(type), di);
+
+	di->CompositeType.name = type->Basic.name;
+	di->CompositeType.tag = irDebugBasicEncoding_structure_type;
+	di->CompositeType.size = ir_debug_size_bits(type);
+
+	Type *field_type = base_complex_elem_type(type);
+
+	// @QuaternionLayout
+	irDebugInfo *imag_di = ir_add_debug_info_field_internal(module, str_lit("imag"), field_type, 0*cast(i32)type_size_of(field_type), nullptr, di);
+	irDebugInfo *jmag_di = ir_add_debug_info_field_internal(module, str_lit("jmag"), field_type, 1*cast(i32)type_size_of(field_type), nullptr, di);
+	irDebugInfo *kmag_di = ir_add_debug_info_field_internal(module, str_lit("kmag"), field_type, 2*cast(i32)type_size_of(field_type), nullptr, di);
+	irDebugInfo *real_di = ir_add_debug_info_field_internal(module, str_lit("real"), field_type, 3*cast(i32)type_size_of(field_type), nullptr, di);
+
+	map_set(&module->debug_info, hash_pointer(imag_di), imag_di);
+	map_set(&module->debug_info, hash_pointer(jmag_di), jmag_di);
+	map_set(&module->debug_info, hash_pointer(kmag_di), kmag_di);
+	map_set(&module->debug_info, hash_pointer(real_di), real_di);
+
+	irDebugInfo *elements_di = ir_add_debug_info_array(module, 0, 4);
+	array_add(&elements_di->DebugInfoArray.elements, imag_di);
+	array_add(&elements_di->DebugInfoArray.elements, jmag_di);
+	array_add(&elements_di->DebugInfoArray.elements, kmag_di);
+	array_add(&elements_di->DebugInfoArray.elements, real_di);
+	di->CompositeType.elements = elements_di;
+	map_set(&module->debug_info, hash_pointer(elements_di), elements_di);
+
+	return di;
+}
+
 irDebugInfo *ir_add_debug_info_proc_type(irModule *module, Type *type) {
 	GB_ASSERT(type->kind == Type_Proc);
 
@@ -2377,10 +2432,14 @@ irDebugInfo *ir_add_debug_info_type(irModule *module, Type *type, Entity *e, irD
 	if (type->kind == Type_Basic) {
 		switch (type->Basic.kind) {
 		// Composite basic types
-		case Basic_complex64:
-		case Basic_complex128: return ir_add_debug_info_type_complex(module, type);
-		case Basic_string:     return ir_add_debug_info_type_string(module, scope, e, type);
-		case Basic_any:        return ir_add_debug_info_type_any(module);
+		case Basic_complex64: case Basic_complex128:
+			return ir_add_debug_info_type_complex(module, type);
+		case Basic_quaternion128: case Basic_quaternion256:
+			return ir_add_debug_info_type_quaternion(module, type);
+		case Basic_string:
+			return ir_add_debug_info_type_string(module, scope, e, type);
+		case Basic_any:
+			return ir_add_debug_info_type_any(module);
 
 		// Derived basic types
 		case Basic_cstring:
@@ -2920,10 +2979,6 @@ void ir_emit_unreachable(irProcedure *proc) {
 	ir_emit(proc, ir_instr_unreachable(proc));
 }
 
-irValue *ir_emit_transmute(irProcedure *proc, irValue *value, Type *t);
-irValue *ir_address_from_load_or_generate_local(irProcedure *proc, irValue *val);
-irValue *ir_emit_struct_ep(irProcedure *proc, irValue *s, i32 index);
-
 
 irValue *ir_get_package_value(irModule *m, String package_name, String entity_name) {
 	AstPackage *rt_pkg = get_core_package(m->info, package_name);
@@ -2973,7 +3028,7 @@ Array<irValue *> ir_value_to_array(irProcedure *p, irValue *value) {
 }
 
 
-irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, ProcInlining inlining = ProcInlining_none, bool use_return_ptr_hint = false) {
+irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> const &args, ProcInlining inlining = ProcInlining_none, bool use_return_ptr_hint = false) {
 	Type *pt = base_type(ir_type(value));
 	GB_ASSERT(pt->kind == Type_Proc);
 	Type *results = pt->Proc.results;
@@ -2983,6 +3038,8 @@ irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, Pro
 		context_ptr = ir_find_or_generate_context_ptr(p);
 	}
 
+	set_procedure_abi_types(heap_allocator(), pt);
+
 	bool is_c_vararg = pt->Proc.c_vararg;
 	isize param_count = pt->Proc.param_count;
 	if (is_c_vararg) {
@@ -2991,9 +3048,13 @@ irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, Pro
 	} else {
 		GB_ASSERT_MSG(param_count == args.count, "%td == %td", param_count, args.count);
 	}
+
+	auto processed_args = array_make<irValue *>(heap_allocator(), 0, args.count);
+
 	for (isize i = 0; i < param_count; i++) {
 		Entity *e = pt->Proc.params->Tuple.variables[i];
 		if (e->kind != Entity_Variable) {
+			array_add(&processed_args, args[i]);
 			continue;
 		}
 		GB_ASSERT(e->flags & EntityFlag_Param);
@@ -3003,21 +3064,32 @@ irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, Pro
 		Type *arg_type = ir_type(args[i]);
 		if (are_types_identical(arg_type, new_type)) {
 			// NOTE(bill): Done
+			array_add(&processed_args, args[i]);
 		} else if (!are_types_identical(original_type, new_type)) {
-
 			if (is_type_pointer(new_type) && !is_type_pointer(original_type)) {
-				if (e->flags&EntityFlag_Value) {
-					args[i] = ir_address_from_load_or_generate_local(p, args[i]);
+				if (e->flags&EntityFlag_ImplicitReference) {
+					array_add(&processed_args, ir_address_from_load_or_generate_local(p, args[i]));
 				} else if (!is_type_pointer(arg_type)) {
-					args[i] = ir_copy_value_to_ptr(p, args[i], original_type, 16);
+					array_add(&processed_args, ir_copy_value_to_ptr(p, args[i], original_type, 16));
 				}
 			} else if (is_type_integer(new_type)) {
-				args[i] = ir_emit_transmute(p, args[i], new_type);
+				array_add(&processed_args, ir_emit_transmute(p, args[i], new_type));
 			} else if (new_type == t_llvm_bool) {
-				args[i] = ir_emit_conv(p, args[i], new_type);
+				array_add(&processed_args, ir_emit_conv(p, args[i], new_type));
 			} else if (is_type_simd_vector(new_type)) {
-				args[i] = ir_emit_bitcast(p, args[i], new_type);
+				array_add(&processed_args, ir_emit_bitcast(p, args[i], new_type));
+			} else if (is_type_tuple(new_type)) {
+				Type *abi_type = pt->Proc.abi_compat_params[i];
+				Type *st = struct_type_from_systemv_distribute_struct_fields(abi_type);
+				irValue *x = ir_emit_transmute(p, args[i], st);
+				for (isize j = 0; j < new_type->Tuple.variables.count; j++) {
+					irValue *xx = ir_emit_struct_ev(p, x, cast(i32)j);
+					array_add(&processed_args, xx);
+				}
 			}
+		} else {
+			irValue *x = ir_emit_conv(p, args[i], new_type);
+			array_add(&processed_args, x);
 		}
 	}
 
@@ -3042,10 +3114,10 @@ irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, Pro
 			return_ptr = ir_add_local_generated(p, rt, true);
 		}
 		GB_ASSERT(is_type_pointer(ir_type(return_ptr)));
-		ir_emit(p, ir_instr_call(p, value, return_ptr, args, nullptr, context_ptr, inlining));
+		ir_emit(p, ir_instr_call(p, value, return_ptr, processed_args, nullptr, context_ptr, inlining));
 		result = ir_emit_load(p, return_ptr);
 	} else {
-		result = ir_emit(p, ir_instr_call(p, value, nullptr, args, abi_rt, context_ptr, inlining));
+		result = ir_emit(p, ir_instr_call(p, value, nullptr, processed_args, abi_rt, context_ptr, inlining));
 		if (abi_rt != results) {
 			result = ir_emit_transmute(p, result, rt);
 		}
@@ -3054,7 +3126,7 @@ irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, Pro
 	if (value->kind == irValue_Proc) {
 		irProcedure *the_proc = &value->Proc;
 		Entity *e = the_proc->entity;
-		if (entity_has_deferred_procedure(e)) {
+		if (e != nullptr && entity_has_deferred_procedure(e)) {
 			DeferredProcedureKind kind = e->Procedure.deferred_procedure.kind;
 			Entity *deferred_entity = e->Procedure.deferred_procedure.entity;
 			irValue **deferred_found = map_get(&p->module->values, hash_entity(deferred_entity));
@@ -3653,12 +3725,12 @@ struct irLoopData {
 	irBlock *loop;
 };
 
-irLoopData ir_loop_start(irProcedure *proc, isize count) {
+irLoopData ir_loop_start(irProcedure *proc, isize count, Type *index_type=t_int) {
 	irLoopData data = {};
 
 	irValue *max = ir_const_int(count);
 
-	data.idx_addr = ir_add_local_generated(proc, t_int, true);
+	data.idx_addr = ir_add_local_generated(proc, index_type, true);
 
 	data.body = ir_new_block(proc, nullptr, "loop.body");
 	data.done = ir_new_block(proc, nullptr, "loop.done");
@@ -3728,7 +3800,7 @@ irValue *ir_emit_unary_arith(irProcedure *proc, TokenKind op, irValue *x, Type *
 				ir_emit_store(proc, ir_emit_array_epi(proc, res, i), z);
 			}
 		} else {
-			auto loop_data = ir_loop_start(proc, count);
+			auto loop_data = ir_loop_start(proc, count, t_i32);
 
 			irValue *e = ir_emit_load(proc, ir_emit_array_ep(proc, val, loop_data.idx));
 			irValue *z = ir_emit_unary_arith(proc, op, e, elem_type);
@@ -3787,7 +3859,7 @@ irValue *ir_emit_arith(irProcedure *proc, TokenKind op, irValue *left, irValue *
 				ir_emit_store(proc, ir_emit_array_epi(proc, res, i), z);
 			}
 		} else {
-			auto loop_data = ir_loop_start(proc, count);
+			auto loop_data = ir_loop_start(proc, count, t_i32);
 
 			irValue *x = ir_emit_load(proc, ir_emit_array_ep(proc, lhs, loop_data.idx));
 			irValue *y = ir_emit_load(proc, ir_emit_array_ep(proc, rhs, loop_data.idx));
@@ -3853,6 +3925,60 @@ irValue *ir_emit_arith(irProcedure *proc, TokenKind op, irValue *left, irValue *
 		return ir_emit_load(proc, res);
 	}
 
+	if (is_type_quaternion(t_left)) {
+		ir_emit_comment(proc, str_lit("complex.arith.begin"));
+		defer (ir_emit_comment(proc, str_lit("complex.arith.end")));
+
+		right = ir_emit_conv(proc, right, t_left);
+
+		Type *ft = base_complex_elem_type(t_left);
+
+		if (op == Token_Add || op == Token_Sub) {
+			irValue *res = ir_add_local_generated(proc, type, false); // NOTE: initialized in full later
+			irValue *x0 = ir_emit_struct_ev(proc, left,  0);
+			irValue *x1 = ir_emit_struct_ev(proc, left,  1);
+			irValue *x2 = ir_emit_struct_ev(proc, left,  2);
+			irValue *x3 = ir_emit_struct_ev(proc, left,  3);
+
+			irValue *y0 = ir_emit_struct_ev(proc, right, 0);
+			irValue *y1 = ir_emit_struct_ev(proc, right, 1);
+			irValue *y2 = ir_emit_struct_ev(proc, right, 2);
+			irValue *y3 = ir_emit_struct_ev(proc, right, 3);
+
+			irValue *z0 = ir_emit_arith(proc, op, x0, y0, ft);
+			irValue *z1 = ir_emit_arith(proc, op, x1, y1, ft);
+			irValue *z2 = ir_emit_arith(proc, op, x2, y2, ft);
+			irValue *z3 = ir_emit_arith(proc, op, x3, y3, ft);
+
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 0), z0);
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 1), z1);
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 2), z2);
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 3), z3);
+
+			return ir_emit_load(proc, res);
+		} else if (op == Token_Mul) {
+			auto args = array_make<irValue *>(heap_allocator(), 2);
+			args[0] = left;
+			args[1] = right;
+
+			switch (8*type_size_of(ft)) {
+			case 32: return ir_emit_runtime_call(proc, "mul_quaternion128", args);
+			case 64: return ir_emit_runtime_call(proc, "mul_quaternion256", args);
+			default: GB_PANIC("Unknown float type"); break;
+			}
+		} else if (op == Token_Quo) {
+			auto args = array_make<irValue *>(heap_allocator(), 2);
+			args[0] = left;
+			args[1] = right;
+
+			switch (8*type_size_of(ft)) {
+			case 32: return ir_emit_runtime_call(proc, "quo_quaternion128", args);
+			case 64: return ir_emit_runtime_call(proc, "quo_quaternion256", args);
+			default: GB_PANIC("Unknown float type"); break;
+			}
+		}
+	}
+
 
 #if 0
 	if (op == Token_Add) {
@@ -4018,6 +4144,15 @@ irValue *ir_emit_comp_against_nil(irProcedure *proc, TokenKind op_kind, irValue
 	} else if (is_type_typeid(t)) {
 		irValue *invalid_typeid = ir_value_constant(t_typeid, exact_value_i64(0));
 		return ir_emit_comp(proc, op_kind, x, invalid_typeid);
+	} else if (is_type_bit_field(t)) {
+		auto args = array_make<irValue *>(heap_allocator(), 2);
+		irValue *lhs = ir_address_from_load_or_generate_local(proc, x);
+		args[0] = ir_emit_conv(proc, lhs, t_rawptr);
+		args[1] = ir_const_int(type_size_of(t));
+		irValue *val = ir_emit_runtime_call(proc, "memory_compare_zero", args);
+		irValue *res = ir_emit_comp(proc, op_kind, val, v_zero);
+		return ir_emit_conv(proc, res, t_bool);
+
 	}
 	return nullptr;
 }
@@ -4105,6 +4240,9 @@ irValue *ir_emit_comp(irProcedure *proc, TokenKind op_kind, irValue *left, irVal
 		if (op_kind == Token_NotEq) {
 			res = v_false;
 			cmp_op = Token_Or;
+		} else if (op_kind == Token_CmpEq) {
+			res = v_true;
+			cmp_op = Token_And;
 		}
 
 		bool inline_array_arith = type_size_of(tl) <= build_context.max_align;
@@ -4112,28 +4250,43 @@ irValue *ir_emit_comp(irProcedure *proc, TokenKind op_kind, irValue *left, irVal
 
 		if (inline_array_arith) {
 			// inline
+			irValue *val = ir_add_local_generated(proc, t_bool, false);
+			ir_emit_store(proc, val, res);
 			for (i32 i = 0; i < count; i++) {
 				irValue *x = ir_emit_load(proc, ir_emit_array_epi(proc, lhs, i));
 				irValue *y = ir_emit_load(proc, ir_emit_array_epi(proc, rhs, i));
 				irValue *cmp = ir_emit_comp(proc, op_kind, x, y);
-				res = ir_emit_arith(proc, cmp_op, res, cmp, t_bool);
-			}
-
-			return ir_emit_conv(proc, res, t_bool);
-		} else {
-			irValue *val = ir_add_local_generated(proc, t_bool, false);
-			ir_emit_store(proc, val, res);
-			auto loop_data = ir_loop_start(proc, count);
-			{
-				irValue *x = ir_emit_load(proc, ir_emit_array_ep(proc, lhs, loop_data.idx));
-				irValue *y = ir_emit_load(proc, ir_emit_array_ep(proc, rhs, loop_data.idx));
-				irValue *cmp = ir_emit_comp(proc, op_kind, x, y);
-				irValue *new_res = ir_emit_arith(proc, cmp_op, res, cmp, t_bool);
+				irValue *new_res = ir_emit_arith(proc, cmp_op, ir_emit_load(proc, val), cmp, t_bool);
 				ir_emit_store(proc, val, ir_emit_conv(proc, new_res, t_bool));
 			}
-			ir_loop_end(proc, loop_data);
 
 			return ir_emit_load(proc, val);
+		} else {
+			if (is_type_simple_compare(tl) && (op_kind == Token_CmpEq || op_kind == Token_NotEq)) {
+				// TODO(bill): Test to see if this is actually faster!!!!
+				auto args = array_make<irValue *>(heap_allocator(), 3);
+				args[0] = ir_emit_conv(proc, lhs, t_rawptr);
+				args[1] = ir_emit_conv(proc, rhs, t_rawptr);
+				args[2] = ir_const_int(type_size_of(tl));
+				irValue *val = ir_emit_runtime_call(proc, "memory_compare", args);
+				irValue *res = ir_emit_comp(proc, op_kind, val, v_zero);
+				return ir_emit_conv(proc, res, t_bool);
+			} else {
+				irValue *val = ir_add_local_generated(proc, t_bool, false);
+				ir_emit_store(proc, val, res);
+				auto loop_data = ir_loop_start(proc, count, t_i32);
+				{
+					irValue *i = loop_data.idx;
+					irValue *x = ir_emit_load(proc, ir_emit_array_ep(proc, lhs, i));
+					irValue *y = ir_emit_load(proc, ir_emit_array_ep(proc, rhs, i));
+					irValue *cmp = ir_emit_comp(proc, op_kind, x, y);
+					irValue *new_res = ir_emit_arith(proc, cmp_op, ir_emit_load(proc, val), cmp, t_bool);
+					ir_emit_store(proc, val, ir_emit_conv(proc, new_res, t_bool));
+				}
+				ir_loop_end(proc, loop_data);
+
+				return ir_emit_load(proc, val);
+			}
 		}
 	}
 
@@ -4161,7 +4314,7 @@ irValue *ir_emit_comp(irProcedure *proc, TokenKind op_kind, irValue *left, irVal
 	}
 
 	if (is_type_complex(a)) {
-		char *runtime_proc = "";
+		char const *runtime_proc = "";
 		i64 sz = 8*type_size_of(a);
 		switch (sz) {
 		case 64:
@@ -4185,6 +4338,31 @@ irValue *ir_emit_comp(irProcedure *proc, TokenKind op_kind, irValue *left, irVal
 		return ir_emit_runtime_call(proc, runtime_proc, args);
 	}
 
+	if (is_type_quaternion(a)) {
+		char const *runtime_proc = "";
+		i64 sz = 8*type_size_of(a);
+		switch (sz) {
+		case 128:
+			switch (op_kind) {
+			case Token_CmpEq: runtime_proc = "quaternion128_eq"; break;
+			case Token_NotEq: runtime_proc = "quaternion128_ne"; break;
+			}
+			break;
+		case 256:
+			switch (op_kind) {
+			case Token_CmpEq: runtime_proc = "quaternion256_eq"; break;
+			case Token_NotEq: runtime_proc = "quaternion256_ne"; break;
+			}
+			break;
+		}
+		GB_ASSERT(runtime_proc != nullptr);
+
+		auto args = array_make<irValue *>(ir_allocator(), 2);
+		args[0] = left;
+		args[1] = right;
+		return ir_emit_runtime_call(proc, runtime_proc, args);
+	}
+
 	if (is_type_bit_set(a)) {
 		switch (op_kind) {
 		case Token_Lt:
@@ -4268,11 +4446,18 @@ irValue *ir_emit_struct_ep(irProcedure *proc, irValue *s, i32 index) {
 		case 0: result_type = alloc_type_pointer(ft); break;
 		case 1: result_type = alloc_type_pointer(ft); break;
 		}
+	} else if (is_type_quaternion(t)) {
+		Type *ft = base_complex_elem_type(t);
+		switch (index) {
+		case 0: result_type = alloc_type_pointer(ft); break;
+		case 1: result_type = alloc_type_pointer(ft); break;
+		case 2: result_type = alloc_type_pointer(ft); break;
+		case 3: result_type = alloc_type_pointer(ft); break;
+		}
 	} else if (is_type_slice(t)) {
 		switch (index) {
 		case 0: result_type = alloc_type_pointer(alloc_type_pointer(t->Slice.elem)); break;
 		case 1: result_type = alloc_type_pointer(t_int); break;
-		case 2: result_type = alloc_type_pointer(t_int); break;
 		}
 	} else if (is_type_string(t)) {
 		switch (index) {
@@ -4343,6 +4528,17 @@ irValue *ir_emit_struct_ev(irProcedure *proc, irValue *s, i32 index) {
 			}
 			break;
 		}
+		case Basic_quaternion128: case Basic_quaternion256:
+		{
+			Type *ft = base_complex_elem_type(t);
+			switch (index) {
+			case 0: result_type = ft; break;
+			case 1: result_type = ft; break;
+			case 2: result_type = ft; break;
+			case 3: result_type = ft; break;
+			}
+			break;
+		}
 		}
 		break;
 	case Type_Struct:
@@ -4401,13 +4597,14 @@ irValue *ir_emit_deep_field_gep(irProcedure *proc, irValue *e, Selection sel) {
 		if (is_type_pointer(type)) {
 			type = type_deref(type);
 			e = ir_emit_load(proc, e);
-			e = ir_emit_ptr_offset(proc, e, v_zero); // TODO(bill): Do I need these copies?
+			// e = ir_emit_ptr_offset(proc, e, v_zero); // TODO(bill): Do I need these copies?
 		}
 		type = core_type(type);
 
 		if (is_type_raw_union(type)) {
 			type = type->Struct.fields[index]->type;
-			e = ir_emit_conv(proc, e, alloc_type_pointer(type));
+			GB_ASSERT(is_type_pointer(ir_type(e)));
+			e = ir_emit_bitcast(proc, e, alloc_type_pointer(type));
 		} else if (is_type_struct(type)) {
 			type = type->Struct.fields[index]->type;
 			e = ir_emit_struct_ep(proc, e, index);
@@ -4725,6 +4922,8 @@ irValue *ir_emit_conv(irProcedure *proc, irValue *value, Type *t) {
 				ev = exact_value_to_float(ev);
 			} else if (is_type_complex(dst)) {
 				ev = exact_value_to_complex(ev);
+			} else if (is_type_quaternion(dst)) {
+				ev = exact_value_to_quaternion(ev);
 			} else if (is_type_string(dst)) {
 				// Handled elsewhere
 				GB_ASSERT_MSG(ev.kind == ExactValue_String, "%d", ev.kind);
@@ -4848,6 +5047,49 @@ irValue *ir_emit_conv(irProcedure *proc, irValue *value, Type *t) {
 		return ir_emit_load(proc, gen);
 	}
 
+	if (is_type_quaternion(src) && is_type_quaternion(dst)) {
+		// @QuaternionLayout
+		Type *ft = base_complex_elem_type(dst);
+		irValue *gen = ir_add_local_generated(proc, dst, false);
+		irValue *q0 = ir_emit_conv(proc, ir_emit_struct_ev(proc, value, 0), ft);
+		irValue *q1 = ir_emit_conv(proc, ir_emit_struct_ev(proc, value, 1), ft);
+		irValue *q2 = ir_emit_conv(proc, ir_emit_struct_ev(proc, value, 2), ft);
+		irValue *q3 = ir_emit_conv(proc, ir_emit_struct_ev(proc, value, 3), ft);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 0), q0);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 1), q1);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 2), q2);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 3), q3);
+		return ir_emit_load(proc, gen);
+	}
+
+	if (is_type_float(src) && is_type_complex(dst)) {
+		Type *ft = base_complex_elem_type(dst);
+		irValue *gen = ir_add_local_generated(proc, dst, true);
+		irValue *real = ir_emit_conv(proc, value, ft);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 0), real);
+		return ir_emit_load(proc, gen);
+	}
+	if (is_type_float(src) && is_type_quaternion(dst)) {
+		Type *ft = base_complex_elem_type(dst);
+		irValue *gen = ir_add_local_generated(proc, dst, true);
+		irValue *real = ir_emit_conv(proc, value, ft);
+		// @QuaternionLayout
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 3), real);
+		return ir_emit_load(proc, gen);
+	}
+	if (is_type_complex(src) && is_type_quaternion(dst)) {
+		Type *ft = base_complex_elem_type(dst);
+		irValue *gen = ir_add_local_generated(proc, dst, true);
+		irValue *real = ir_emit_conv(proc, ir_emit_struct_ev(proc, value, 0), ft);
+		irValue *imag = ir_emit_conv(proc, ir_emit_struct_ev(proc, value, 1), ft);
+		// @QuaternionLayout
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 3), real);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, gen, 0), imag);
+		return ir_emit_load(proc, gen);
+	}
+
+
+
 	// float <-> integer
 	if (is_type_float(src) && is_type_integer(dst)) {
 		irConvKind kind = irConv_fptosi;
@@ -5245,12 +5487,14 @@ gb_global irValue *ir_global_type_info_member_types   = nullptr;
 gb_global irValue *ir_global_type_info_member_names   = nullptr;
 gb_global irValue *ir_global_type_info_member_offsets = nullptr;
 gb_global irValue *ir_global_type_info_member_usings  = nullptr;
+gb_global irValue *ir_global_type_info_member_tags    = nullptr;
 
 gb_global i32      ir_global_type_info_data_index           = 0;
 gb_global i32      ir_global_type_info_member_types_index   = 0;
 gb_global i32      ir_global_type_info_member_names_index   = 0;
 gb_global i32      ir_global_type_info_member_offsets_index = 0;
 gb_global i32      ir_global_type_info_member_usings_index  = 0;
+gb_global i32      ir_global_type_info_member_tags_index    = 0;
 
 isize ir_type_info_count(CheckerInfo *info) {
 	return info->minimum_dependency_type_info_set.entries.count+1;
@@ -5286,6 +5530,7 @@ enum Typeid_Kind : u8 {
 	Typeid_Rune,
 	Typeid_Float,
 	Typeid_Complex,
+	Typeid_Quaternion,
 	Typeid_String,
 	Typeid_Boolean,
 	Typeid_Any,
@@ -5402,7 +5647,8 @@ irValue *ir_emit_logical_binary_expr(irProcedure *proc, TokenKind op, Ast *left,
 	}
 
 	ir_start_block(proc, rhs);
-	array_add(&edges, ir_build_expr(proc, right));
+	irValue *edge = ir_build_expr(proc, right);
+	array_add(&edges, edge);
 	ir_emit_jump(proc, done);
 	ir_start_block(proc, done);
 
@@ -5411,8 +5657,6 @@ irValue *ir_emit_logical_binary_expr(irProcedure *proc, TokenKind op, Ast *left,
 
 irValue *ir_emit_logical_binary_expr(irProcedure *proc, Ast *expr) {
 	ast_node(be, BinaryExpr, expr);
-	irBlock *rhs  = ir_new_block(proc, nullptr, "logical.cmp.rhs");
-	irBlock *done = ir_new_block(proc, nullptr, "logical.cmp.done");
 
 	Type *type = type_of_expr(expr);
 	type = default_type(type);
@@ -6038,17 +6282,77 @@ irValue *ir_build_builtin_proc(irProcedure *proc, Ast *expr, TypeAndValue tv, Bu
 		return ir_emit_load(proc, dst);
 	}
 
+	case BuiltinProc_quaternion: {
+		ir_emit_comment(proc, str_lit("quaternion"));
+		irValue *real = ir_build_expr(proc, ce->args[0]);
+		irValue *imag = ir_build_expr(proc, ce->args[1]);
+		irValue *jmag = ir_build_expr(proc, ce->args[2]);
+		irValue *kmag = ir_build_expr(proc, ce->args[3]);
+
+		// @QuaternionLayout
+		irValue *dst = ir_add_local_generated(proc, tv.type, false);
+		Type *ft = base_complex_elem_type(tv.type);
+		real = ir_emit_conv(proc, real, ft);
+		imag = ir_emit_conv(proc, imag, ft);
+		jmag = ir_emit_conv(proc, jmag, ft);
+		kmag = ir_emit_conv(proc, kmag, ft);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, dst, 3), real);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, dst, 0), imag);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, dst, 1), jmag);
+		ir_emit_store(proc, ir_emit_struct_ep(proc, dst, 2), kmag);
+
+		return ir_emit_load(proc, dst);
+	}
+
 	case BuiltinProc_real: {
 		ir_emit_comment(proc, str_lit("real"));
 		irValue *val = ir_build_expr(proc, ce->args[0]);
-		irValue *real = ir_emit_struct_ev(proc, val, 0);
-		return ir_emit_conv(proc, real, tv.type);
+		if (is_type_complex(ir_type(val))) {
+			irValue *real = ir_emit_struct_ev(proc, val, 0);
+			return ir_emit_conv(proc, real, tv.type);
+		} else if (is_type_quaternion(ir_type(val))) {
+			// @QuaternionLayout
+			irValue *real = ir_emit_struct_ev(proc, val, 3);
+			return ir_emit_conv(proc, real, tv.type);
+		}
+		GB_PANIC("invalid type for real");
+		return nullptr;
 	}
 	case BuiltinProc_imag: {
 		ir_emit_comment(proc, str_lit("imag"));
 		irValue *val = ir_build_expr(proc, ce->args[0]);
-		irValue *imag = ir_emit_struct_ev(proc, val, 1);
-		return ir_emit_conv(proc, imag, tv.type);
+		if (is_type_complex(ir_type(val))) {
+			irValue *imag = ir_emit_struct_ev(proc, val, 1);
+			return ir_emit_conv(proc, imag, tv.type);
+		} else if (is_type_quaternion(ir_type(val))) {
+			// @QuaternionLayout
+			irValue *imag = ir_emit_struct_ev(proc, val, 0);
+			return ir_emit_conv(proc, imag, tv.type);
+		}
+		GB_PANIC("invalid type for imag");
+		return nullptr;
+	}
+	case BuiltinProc_jmag: {
+		ir_emit_comment(proc, str_lit("jmag"));
+		irValue *val = ir_build_expr(proc, ce->args[0]);
+		if (is_type_quaternion(ir_type(val))) {
+			// @QuaternionLayout
+			irValue *imag = ir_emit_struct_ev(proc, val, 1);
+			return ir_emit_conv(proc, imag, tv.type);
+		}
+		GB_PANIC("invalid type for jmag");
+		return nullptr;
+	}
+	case BuiltinProc_kmag: {
+		ir_emit_comment(proc, str_lit("kmag"));
+		irValue *val = ir_build_expr(proc, ce->args[0]);
+		if (is_type_quaternion(ir_type(val))) {
+			// @QuaternionLayout
+			irValue *imag = ir_emit_struct_ev(proc, val, 2);
+			return ir_emit_conv(proc, imag, tv.type);
+		}
+		GB_PANIC("invalid type for kmag");
+		return nullptr;
 	}
 
 	case BuiltinProc_conj: {
@@ -6063,6 +6367,20 @@ irValue *ir_build_builtin_proc(irProcedure *proc, Ast *expr, TypeAndValue tv, Bu
 			imag = ir_emit_unary_arith(proc, Token_Sub, imag, ir_type(imag));
 			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 0), real);
 			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 1), imag);
+		} else if (is_type_quaternion(t)) {
+			// @QuaternionLayout
+			res = ir_add_local_generated(proc, tv.type, false);
+			irValue *real = ir_emit_struct_ev(proc, val, 3);
+			irValue *imag = ir_emit_struct_ev(proc, val, 0);
+			irValue *jmag = ir_emit_struct_ev(proc, val, 1);
+			irValue *kmag = ir_emit_struct_ev(proc, val, 2);
+			imag = ir_emit_unary_arith(proc, Token_Sub, imag, ir_type(imag));
+			jmag = ir_emit_unary_arith(proc, Token_Sub, jmag, ir_type(jmag));
+			kmag = ir_emit_unary_arith(proc, Token_Sub, kmag, ir_type(kmag));
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 3), real);
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 0), imag);
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 1), jmag);
+			ir_emit_store(proc, ir_emit_struct_ep(proc, res, 2), kmag);
 		}
 		return ir_emit_load(proc, res);
 	}
@@ -6133,7 +6451,16 @@ irValue *ir_build_builtin_proc(irProcedure *proc, Ast *expr, TypeAndValue tv, Bu
 			return x;
 		}
 		ir_emit_comment(proc, str_lit("abs"));
-		if (is_type_complex(t)) {
+		if (is_type_quaternion(t)) {
+			i64 sz = 8*type_size_of(t);
+			auto args = array_make<irValue *>(ir_allocator(), 1);
+			args[0] = x;
+			switch (sz) {
+			case 128: return ir_emit_runtime_call(proc, "abs_quaternion128", args);
+			case 256: return ir_emit_runtime_call(proc, "abs_quaternion256", args);
+			}
+			GB_PANIC("Unknown complex type");
+		} else if (is_type_complex(t)) {
 			i64 sz = 8*type_size_of(t);
 			auto args = array_make<irValue *>(ir_allocator(), 1);
 			args[0] = x;
@@ -6312,6 +6639,11 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 			return ir_emit_conv(proc, x, tv.type);
 		}
 
+		if (tv.value.kind == ExactValue_Typeid) {
+			irValue *v = ir_typeid(proc->module, tv.value.value_typeid);
+			return ir_emit_conv(proc, v, tv.type);
+		}
+
 		return ir_add_module_constant(proc->module, tv.type, tv.value);
 	}
 
@@ -6546,9 +6878,6 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 	case_end;
 
 	case_ast_node(be, BinaryExpr, expr);
-		irValue *left = ir_build_expr(proc, be->left);
-		Type *type = default_type(tv.type);
-
 		switch (be->op.kind) {
 		case Token_Add:
 		case Token_Sub:
@@ -6562,6 +6891,8 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 		case Token_AndNot:
 		case Token_Shl:
 		case Token_Shr: {
+			irValue *left = ir_build_expr(proc, be->left);
+			Type *type = default_type(tv.type);
 			irValue *right = ir_build_expr(proc, be->right);
 			return ir_emit_arith(proc, be->op.kind, left, right, type);
 		}
@@ -6573,10 +6904,11 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 		case Token_LtEq:
 		case Token_Gt:
 		case Token_GtEq: {
+			irValue *left = ir_build_expr(proc, be->left);
+			Type *type = default_type(tv.type);
 			irValue *right = ir_build_expr(proc, be->right);
 			irValue *cmp = ir_emit_comp(proc, be->op.kind, left, right);
 			return ir_emit_conv(proc, cmp, type);
-			break;
 		}
 
 		case Token_CmpAnd:
@@ -6586,6 +6918,8 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 
 		case Token_in:
 		case Token_notin: {
+			irValue *left = ir_build_expr(proc, be->left);
+			Type *type = default_type(tv.type);
 			irValue *right = ir_build_expr(proc, be->right);
 			Type *rt = base_type(ir_type(right));
 			switch (rt->kind) {
@@ -6687,7 +7021,34 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 		}
 
 		// NOTE(bill): Regular call
-		irValue *value = ir_build_expr(proc, ce->proc);
+		irValue *value = nullptr;
+		Ast *proc_expr = unparen_expr(ce->proc);
+		if (proc_expr->tav.mode == Addressing_Constant) {
+			ExactValue v = proc_expr->tav.value;
+			switch (v.kind) {
+			case ExactValue_Integer:
+				{
+					u64 u = big_int_to_u64(&v.value_integer);
+					irValue *x = ir_const_uintptr(u);
+					x = ir_emit_conv(proc, x, t_rawptr);
+					value = ir_emit_conv(proc, x, proc_expr->tav.type);
+					break;
+				}
+			case ExactValue_Pointer:
+				{
+					u64 u = cast(u64)v.value_pointer;
+					irValue *x = ir_const_uintptr(u);
+					x = ir_emit_conv(proc, x, t_rawptr);
+					value = ir_emit_conv(proc, x, proc_expr->tav.type);
+					break;
+				}
+			}
+		}
+
+		if (value == nullptr) {
+			value = ir_build_expr(proc, proc_expr);
+		}
+
 		GB_ASSERT(value != nullptr);
 		Type *proc_type_ = base_type(ir_type(value));
 		GB_ASSERT(proc_type_->kind == Type_Proc);
@@ -7501,13 +7862,55 @@ irAddr ir_build_addr(irProcedure *proc, Ast *expr) {
 				// NOTE(bill): Separate value, gep, store into their own chunks
 				for_array(i, cl->elems) {
 					Ast *elem = cl->elems[i];
-					if (ir_is_elem_const(proc->module, elem, et)) {
-						continue;
+					if (elem->kind == Ast_FieldValue) {
+						ast_node(fv, FieldValue, elem);
+						if (ir_is_elem_const(proc->module, fv->value, et)) {
+							continue;
+						}
+						if (is_ast_range(fv->field)) {
+							ast_node(ie, BinaryExpr, fv->field);
+							TypeAndValue lo_tav = ie->left->tav;
+							TypeAndValue hi_tav = ie->right->tav;
+							GB_ASSERT(lo_tav.mode == Addressing_Constant);
+							GB_ASSERT(hi_tav.mode == Addressing_Constant);
+
+							TokenKind op = ie->op.kind;
+							i64 lo = exact_value_to_i64(lo_tav.value);
+							i64 hi = exact_value_to_i64(hi_tav.value);
+							if (op == Token_Ellipsis) {
+								hi += 1;
+							}
+
+							irValue *value = ir_build_expr(proc, fv->value);
+
+							for (i64 k = lo; k < hi; k++) {
+								irCompoundLitElemTempData data = {};
+								data.value = value;
+								data.elem_index = cast(i32)k;
+								array_add(&temp_data, data);
+							}
+
+						} else {
+							auto tav = fv->field->tav;
+							GB_ASSERT(tav.mode == Addressing_Constant);
+							i64 index = exact_value_to_i64(tav.value);
+
+							irCompoundLitElemTempData data = {};
+							data.value = ir_emit_conv(proc, ir_build_expr(proc, fv->value), et);
+							data.expr = fv->value;
+							data.elem_index = cast(i32)index;
+							array_add(&temp_data, data);
+						}
+
+					} else {
+						if (ir_is_elem_const(proc->module, elem, et)) {
+							continue;
+						}
+						irCompoundLitElemTempData data = {};
+						data.expr = elem;
+						data.elem_index = cast(i32)i;
+						array_add(&temp_data, data);
 					}
-					irCompoundLitElemTempData data = {};
-					data.expr = elem;
-					data.elem_index = cast(i32)i;
-					array_add(&temp_data, data);
 				}
 
 				for_array(i, temp_data) {
@@ -7522,12 +7925,15 @@ irAddr ir_build_addr(irProcedure *proc, Ast *expr) {
 					defer (proc->return_ptr_hint_value = return_ptr_hint_value);
 					defer (proc->return_ptr_hint_used  = return_ptr_hint_used);
 
+					irValue *field_expr = temp_data[i].value;
 					Ast *expr = temp_data[i].expr;
 
 					proc->return_ptr_hint_value = temp_data[i].gep;
 					proc->return_ptr_hint_ast = unparen_expr(expr);
 
-					irValue *field_expr = ir_build_expr(proc, expr);
+					if (field_expr == nullptr) {
+						field_expr = ir_build_expr(proc, expr);
+					}
 					Type *t = ir_type(field_expr);
 					GB_ASSERT(t->kind != Type_Tuple);
 					irValue *ev = ir_emit_conv(proc, field_expr, et);
@@ -7560,18 +7966,64 @@ irAddr ir_build_addr(irProcedure *proc, Ast *expr) {
 
 				for_array(i, cl->elems) {
 					Ast *elem = cl->elems[i];
-					if (ir_is_elem_const(proc->module, elem, et)) {
-						continue;
-					}
-					irValue *field_expr = ir_build_expr(proc, elem);
-					Type *t = ir_type(field_expr);
-					GB_ASSERT(t->kind != Type_Tuple);
-					irValue *ev = ir_emit_conv(proc, field_expr, et);
+					if (elem->kind == Ast_FieldValue) {
+						ast_node(fv, FieldValue, elem);
+
+						if (ir_is_elem_const(proc->module, fv->value, et)) {
+							continue;
+						}
+
+						if (is_ast_range(fv->field)) {
+							ast_node(ie, BinaryExpr, fv->field);
+							TypeAndValue lo_tav = ie->left->tav;
+							TypeAndValue hi_tav = ie->right->tav;
+							GB_ASSERT(lo_tav.mode == Addressing_Constant);
+							GB_ASSERT(hi_tav.mode == Addressing_Constant);
+
+							TokenKind op = ie->op.kind;
+							i64 lo = exact_value_to_i64(lo_tav.value);
+							i64 hi = exact_value_to_i64(hi_tav.value);
+							if (op == Token_Ellipsis) {
+								hi += 1;
+							}
+
+							irValue *value = ir_emit_conv(proc, ir_build_expr(proc, fv->value), et);
+
+							for (i64 k = lo; k < hi; k++) {
+								irCompoundLitElemTempData data = {};
+								data.value = value;
+								data.elem_index = cast(i32)k;
+								array_add(&temp_data, data);
+							}
+
+						} else {
+							GB_ASSERT(fv->field->tav.mode == Addressing_Constant);
+							i64 index = exact_value_to_i64(fv->field->tav.value);
 
-					irCompoundLitElemTempData data = {};
-					data.value = ev;
-					data.elem_index = cast(i32)i;
-					array_add(&temp_data, data);
+							irValue *field_expr = ir_build_expr(proc, fv->value);
+							GB_ASSERT(!is_type_tuple(ir_type(field_expr)));
+
+							irValue *ev = ir_emit_conv(proc, field_expr, et);
+
+							irCompoundLitElemTempData data = {};
+							data.value = ev;
+							data.elem_index = cast(i32)index;
+							array_add(&temp_data, data);
+						}
+					} else {
+						if (ir_is_elem_const(proc->module, elem, et)) {
+							continue;
+						}
+						irValue *field_expr = ir_build_expr(proc, elem);
+						GB_ASSERT(!is_type_tuple(ir_type(field_expr)));
+
+						irValue *ev = ir_emit_conv(proc, field_expr, et);
+
+						irCompoundLitElemTempData data = {};
+						data.value = ev;
+						data.elem_index = cast(i32)i;
+						array_add(&temp_data, data);
+					}
 				}
 
 				for_array(i, temp_data) {
@@ -7592,28 +8044,64 @@ irAddr ir_build_addr(irProcedure *proc, Ast *expr) {
 			if (cl->elems.count == 0) {
 				break;
 			}
-			Type *elem = bt->DynamicArray.elem;
+			Type *et = bt->DynamicArray.elem;
 			gbAllocator a = ir_allocator();
-			irValue *size  = ir_const_int(type_size_of(elem));
-			irValue *align = ir_const_int(type_align_of(elem));
+			irValue *size  = ir_const_int(type_size_of(et));
+			irValue *align = ir_const_int(type_align_of(et));
+
+			i64 item_count = gb_max(cl->max_count, cl->elems.count);
 			{
+
 				auto args = array_make<irValue *>(a, 5);
 				args[0] = ir_emit_conv(proc, v, t_rawptr);
 				args[1] = size;
 				args[2] = align;
-				args[3] = ir_const_int(2*cl->elems.count);
+				args[3] = ir_const_int(2*item_count); // TODO(bill): Is this too much waste?
 				args[4] = ir_emit_source_code_location(proc, proc_name, pos);
 				ir_emit_runtime_call(proc, "__dynamic_array_reserve", args);
 			}
 
-			i64 item_count = cl->elems.count;
-			irValue *items = ir_generate_array(proc->module, elem, item_count, str_lit("dacl$"), cast(i64)cast(intptr)expr);
+			irValue *items = ir_generate_array(proc->module, et, item_count, str_lit("dacl$"), cast(i64)cast(intptr)expr);
+
+			for_array(i, cl->elems) {
+				Ast *elem = cl->elems[i];
+				if (elem->kind == Ast_FieldValue) {
+					ast_node(fv, FieldValue, elem);
+					if (is_ast_range(fv->field)) {
+						ast_node(ie, BinaryExpr, fv->field);
+						TypeAndValue lo_tav = ie->left->tav;
+						TypeAndValue hi_tav = ie->right->tav;
+						GB_ASSERT(lo_tav.mode == Addressing_Constant);
+						GB_ASSERT(hi_tav.mode == Addressing_Constant);
+
+						TokenKind op = ie->op.kind;
+						i64 lo = exact_value_to_i64(lo_tav.value);
+						i64 hi = exact_value_to_i64(hi_tav.value);
+						if (op == Token_Ellipsis) {
+							hi += 1;
+						}
 
-			for_array(field_index, cl->elems) {
-				Ast *f = cl->elems[field_index];
-				irValue *value = ir_emit_conv(proc, ir_build_expr(proc, f), elem);
-				irValue *ep = ir_emit_array_epi(proc, items, cast(i32)field_index);
-				ir_emit_store(proc, ep, value);
+						irValue *value = ir_emit_conv(proc, ir_build_expr(proc, fv->value), et);
+
+						for (i64 k = lo; k < hi; k++) {
+							irValue *ep = ir_emit_array_epi(proc, items, cast(i32)k);
+							ir_emit_store(proc, ep, value);
+						}
+					} else {
+						GB_ASSERT(fv->field->tav.mode == Addressing_Constant);
+
+						i64 field_index = exact_value_to_i64(fv->field->tav.value);
+
+						irValue *ev = ir_build_expr(proc, fv->value);
+						irValue *value = ir_emit_conv(proc, ev, et);
+						irValue *ep = ir_emit_array_epi(proc, items, cast(i32)field_index);
+						ir_emit_store(proc, ep, value);
+					}
+				} else {
+					irValue *value = ir_emit_conv(proc, ir_build_expr(proc, elem), et);
+					irValue *ep = ir_emit_array_epi(proc, items, cast(i32)i);
+					ir_emit_store(proc, ep, value);
+				}
 			}
 
 			{
@@ -7907,24 +8395,27 @@ void ir_build_constant_value_decl(irProcedure *proc, AstValueDecl *vd) {
 					name = e->Procedure.link_name;
 				}
 
+				HashKey key = hash_string(name);
+				irValue **prev_value = map_get(&proc->module->members, key);
+				if (prev_value != nullptr) {
+					// NOTE(bill): Don't do mutliple declarations in the IR
+					return;
+				}
+
+
 				irValue *value = ir_value_procedure(proc->module, e, e->type, pl->type, pl->body, name);
 
 				value->Proc.tags = pl->tags;
 				value->Proc.inlining = pl->inlining;
 
-				ir_module_add_value(proc->module, e, value);
-				ir_build_proc(value, proc);
-
 				if (value->Proc.is_foreign || value->Proc.is_export) {
-					HashKey key = hash_string(name);
-					irValue **prev_value = map_get(&proc->module->members, key);
-					if (prev_value == nullptr) {
-						// NOTE(bill): Don't do mutliple declarations in the IR
-						map_set(&proc->module->members, key, value);
-					}
+					map_set(&proc->module->members, key, value);
 				} else {
 					array_add(&proc->children, &value->Proc);
 				}
+
+				ir_module_add_value(proc->module, e, value);
+				ir_build_proc(value, proc);
 			}
 		}
 	}
@@ -8806,6 +9297,150 @@ void ir_build_stmt_internal(irProcedure *proc, Ast *node) {
 		ir_start_block(proc, done);
 	case_end;
 
+	case_ast_node(rs, InlineRangeStmt, node);
+		ir_emit_comment(proc, str_lit("InlineRangeStmt"));
+		ir_open_scope(proc); // Open scope here
+
+		Type *val0_type = nullptr;
+		Type *val1_type = nullptr;
+		if (rs->val0 != nullptr && !is_blank_ident(rs->val0)) {
+			val0_type = type_of_expr(rs->val0);
+		}
+		if (rs->val1 != nullptr && !is_blank_ident(rs->val1)) {
+			val1_type = type_of_expr(rs->val1);
+		}
+
+		if (val0_type != nullptr) {
+			ir_add_local_for_identifier(proc, rs->val0, true);
+		}
+		if (val1_type != nullptr) {
+			ir_add_local_for_identifier(proc, rs->val1, true);
+		}
+
+		irValue *val = nullptr;
+		irValue *key = nullptr;
+		irBlock *loop = nullptr;
+		irBlock *done = nullptr;
+		Ast *expr = unparen_expr(rs->expr);
+
+		TypeAndValue tav = type_and_value_of_expr(expr);
+
+		if (is_ast_range(expr)) {
+
+			irAddr val0_addr = {};
+			irAddr val1_addr = {};
+			if (val0_type) val0_addr = ir_build_addr(proc, rs->val0);
+			if (val1_type) val1_addr = ir_build_addr(proc, rs->val1);
+
+			TokenKind op = expr->BinaryExpr.op.kind;
+			Ast *start_expr = expr->BinaryExpr.left;
+			Ast *end_expr   = expr->BinaryExpr.right;
+			GB_ASSERT(start_expr->tav.mode == Addressing_Constant);
+			GB_ASSERT(end_expr->tav.mode == Addressing_Constant);
+
+			ExactValue start = start_expr->tav.value;
+			ExactValue end   = end_expr->tav.value;
+			if (op == Token_Ellipsis) { // .. [start, end]
+				ExactValue index = exact_value_i64(0);
+				for (ExactValue val = start;
+				     compare_exact_values(Token_LtEq, val, end);
+				     val = exact_value_increment_one(val), index = exact_value_increment_one(index)) {
+
+					if (val0_type) ir_addr_store(proc, val0_addr, ir_value_constant(val0_type, val));
+					if (val1_type) ir_addr_store(proc, val1_addr, ir_value_constant(val1_type, index));
+
+					ir_build_stmt(proc, rs->body);
+				}
+			} else if (op == Token_RangeHalf) { // ..< [start, end)
+				ExactValue index = exact_value_i64(0);
+				for (ExactValue val = start;
+				     compare_exact_values(Token_Lt, val, end);
+				     val = exact_value_increment_one(val), index = exact_value_increment_one(index)) {
+
+					if (val0_type) ir_addr_store(proc, val0_addr, ir_value_constant(val0_type, val));
+					if (val1_type) ir_addr_store(proc, val1_addr, ir_value_constant(val1_type, index));
+
+					ir_build_stmt(proc, rs->body);
+				}
+			}
+
+
+		} else if (tav.mode == Addressing_Type) {
+			GB_ASSERT(is_type_enum(type_deref(tav.type)));
+			Type *et = type_deref(tav.type);
+			Type *bet = base_type(et);
+
+			irAddr val0_addr = {};
+			irAddr val1_addr = {};
+			if (val0_type) val0_addr = ir_build_addr(proc, rs->val0);
+			if (val1_type) val1_addr = ir_build_addr(proc, rs->val1);
+
+			for_array(i, bet->Enum.fields) {
+				Entity *field = bet->Enum.fields[i];
+				GB_ASSERT(field->kind == Entity_Constant);
+				if (val0_type) ir_addr_store(proc, val0_addr, ir_value_constant(val0_type, field->Constant.value));
+				if (val1_type) ir_addr_store(proc, val1_addr, ir_value_constant(val1_type, exact_value_i64(i)));
+
+				ir_build_stmt(proc, rs->body);
+			}
+		} else {
+			irAddr val0_addr = {};
+			irAddr val1_addr = {};
+			if (val0_type) val0_addr = ir_build_addr(proc, rs->val0);
+			if (val1_type) val1_addr = ir_build_addr(proc, rs->val1);
+
+			GB_ASSERT(expr->tav.mode == Addressing_Constant);
+
+			Type *t = base_type(expr->tav.type);
+
+
+			switch (t->kind) {
+			case Type_Basic:
+				GB_ASSERT(is_type_string(t));
+				{
+					ExactValue value = expr->tav.value;
+					GB_ASSERT(value.kind == ExactValue_String);
+					String str = value.value_string;
+					Rune codepoint = 0;
+					isize offset = 0;
+					do {
+						isize width = gb_utf8_decode(str.text+offset, str.len-offset, &codepoint);
+						if (val0_type) ir_addr_store(proc, val0_addr, ir_value_constant(val0_type, exact_value_i64(codepoint)));
+						if (val1_type) ir_addr_store(proc, val1_addr, ir_value_constant(val1_type, exact_value_i64(offset)));
+						ir_build_stmt(proc, rs->body);
+
+						offset += width;
+					} while (offset < str.len);
+				}
+				break;
+			case Type_Array:
+				if (t->Array.count > 0) {
+					irValue *val = ir_build_expr(proc, expr);
+					irValue *val_addr = ir_address_from_load_or_generate_local(proc, val);
+
+					for (i64 i = 0; i < t->Array.count; i++) {
+						if (val0_type) {
+							// NOTE(bill): Due to weird legacy issues in LLVM, this needs to be an i32
+							irValue *elem = ir_emit_array_epi(proc, val_addr, cast(i32)i);
+							ir_addr_store(proc, val0_addr, ir_emit_load(proc, elem));
+						}
+						if (val1_type) ir_addr_store(proc, val1_addr, ir_value_constant(val1_type, exact_value_i64(i)));
+
+						ir_build_stmt(proc, rs->body);
+					}
+
+				}
+				break;
+			default:
+				GB_PANIC("Invalid inline for type");
+				break;
+			}
+		}
+
+
+		ir_close_scope(proc, irDeferExit_Default, nullptr);
+	case_end;
+
 	case_ast_node(ss, SwitchStmt, node);
 		ir_emit_comment(proc, str_lit("SwitchStmt"));
 		if (ss->init != nullptr) {
@@ -9084,6 +9719,7 @@ void ir_build_stmt_internal(irProcedure *proc, Ast *node) {
 ////////////////////////////////////////////////////////////////
 
 void ir_number_proc_registers(irProcedure *proc) {
+	// i32 reg_index = proc->parameter_count;
 	i32 reg_index = 0;
 	for_array(i, proc->blocks) {
 		irBlock *b = proc->blocks[i];
@@ -9139,13 +9775,15 @@ void ir_begin_procedure_body(irProcedure *proc) {
 	proc->entry_block = ir_new_block(proc, proc->type_expr, "entry");
 	ir_start_block(proc, proc->entry_block);
 
+	i32 parameter_index = 0;
+
 	if (proc->type->Proc.return_by_pointer) {
 		// NOTE(bill): this must be the first parameter stored
 		Type *ptr_type = alloc_type_pointer(reduce_tuple_to_single_type(proc->type->Proc.results));
 		Entity *e = alloc_entity_param(nullptr, make_token_ident(str_lit("agg.result")), ptr_type, false, false);
 		e->flags |= EntityFlag_Sret | EntityFlag_NoAlias;
 
-		irValue *param = ir_value_param(proc, e, ptr_type);
+		irValue *param = ir_value_param(proc, e, ptr_type, -1);
 		param->Param.kind = irParamPass_Pointer;
 
 		ir_module_add_value(proc->module, e, param);
@@ -9174,13 +9812,19 @@ void ir_begin_procedure_body(irProcedure *proc) {
 
 				Entity *e = params->variables[i];
 				if (e->kind != Entity_Variable) {
+					parameter_index += 1;
 					continue;
 				}
 
 				Type *abi_type = proc->type->Proc.abi_compat_params[i];
-				if (e->token.string != "" && !is_blank_ident(e->token)) {
-					irValue *param = ir_add_param(proc, e, name, abi_type, cast(i32)(i+1));
-					array_add(&proc->params, param);
+				if (e->token.string != "") {
+					ir_add_param(proc, e, name, abi_type, parameter_index);
+				}
+
+				if (is_type_tuple(abi_type)) {
+					parameter_index += cast(i32)abi_type->Tuple.variables.count;
+				} else {
+					parameter_index += 1;
 				}
 			}
 		} else {
@@ -9189,15 +9833,20 @@ void ir_begin_procedure_body(irProcedure *proc) {
 			for_array(i, params->variables) {
 				Entity *e = params->variables[i];
 				if (e->kind != Entity_Variable) {
+					parameter_index += 1;
 					continue;
 				}
 				Type *abi_type = e->type;
 				if (abi_types.count > 0) {
 					abi_type = abi_types[i];
 				}
-				if (e->token.string != "" && !is_blank_ident(e->token)) {
-					irValue *param = ir_add_param(proc, e, nullptr, abi_type, cast(i32)(i+1));
-					array_add(&proc->params, param);
+				if (e->token.string != "") {
+					ir_add_param(proc, e, nullptr, abi_type, parameter_index);
+				}
+				if (is_type_tuple(abi_type)) {
+					parameter_index += cast(i32)abi_type->Tuple.variables.count;
+				} else {
+					parameter_index += 1;
 				}
 			}
 		}
@@ -9239,11 +9888,13 @@ void ir_begin_procedure_body(irProcedure *proc) {
 	if (proc->type->Proc.calling_convention == ProcCC_Odin) {
 		Entity *e = alloc_entity_param(nullptr, make_token_ident(str_lit("__.context_ptr")), t_context_ptr, false, false);
 		e->flags |= EntityFlag_NoAlias;
-		irValue *param = ir_value_param(proc, e, e->type);
+		irValue *param = ir_value_param(proc, e, e->type, -1);
 		ir_module_add_value(proc->module, e, param);
 		irContextData ctx = {param, proc->scope_index};
 		array_add(&proc->context_stack, ctx);
 	}
+
+	proc->parameter_count = parameter_index;
 }
 
 
@@ -9370,6 +10021,8 @@ void ir_insert_code_before_proc(irProcedure* proc, irProcedure *parent) {
 void ir_build_proc(irValue *value, irProcedure *parent) {
 	irProcedure *proc = &value->Proc;
 
+	set_procedure_abi_types(heap_allocator(), proc->type);
+
 	proc->parent = parent;
 
 	if (proc->body != nullptr) {
@@ -9561,13 +10214,27 @@ void ir_init_module(irModule *m, Checker *c) {
 					map_set(&m->members, hash_string(name), g);
 					ir_global_type_info_member_usings = g;
 				}
+
+				{
+					String name = str_lit(IR_TYPE_INFO_TAGS_NAME);
+					Entity *e = alloc_entity_variable(nullptr, make_token_ident(name),
+					                                  alloc_type_array(t_string, count), false);
+					irValue *g = ir_value_global(e, nullptr);
+					ir_module_add_value(m, e, g);
+					map_set(&m->members, hash_string(name), g);
+					ir_global_type_info_member_tags = g;
+				}
 			}
 		}
 	}
 
 	{
 		irDebugInfo *di = ir_alloc_debug_info(irDebugInfo_CompileUnit);
-		di->CompileUnit.file = m->info->files.entries[0].value; // Zeroth is the init file
+
+		GB_ASSERT(m->info->files.entries.count > 0);
+		AstFile *file = m->info->files.entries[0].value;
+
+		di->CompileUnit.file = file; // Zeroth is the init file
 		di->CompileUnit.producer = str_lit("odin");
 
 		map_set(&m->debug_info, hash_pointer(m), di);
@@ -9586,6 +10253,13 @@ void ir_init_module(irModule *m, Checker *c) {
 
 		array_init(&m->debug_location_stack, heap_allocator()); // TODO(lachsinc): ir_allocator() ??
 	}
+
+	{
+		for_array(i, m->info->files.entries) {
+			AstFile *file = m->info->files.entries[i].value;
+			ir_add_debug_info_file(m, file);
+		}
+	}
 }
 
 void ir_destroy_module(irModule *m) {
@@ -9694,6 +10368,11 @@ irValue *ir_type_info_member_usings_offset(irProcedure *proc, isize count) {
 	ir_global_type_info_member_usings_index += cast(i32)count;
 	return offset;
 }
+irValue *ir_type_info_member_tags_offset(irProcedure *proc, isize count) {
+	irValue *offset = ir_emit_array_epi(proc, ir_global_type_info_member_tags, ir_global_type_info_member_tags_index);
+	ir_global_type_info_member_tags_index += cast(i32)count;
+	return offset;
+}
 
 
 
@@ -9832,6 +10511,11 @@ void ir_setup_type_info_data(irProcedure *proc) { // NOTE(bill): Setup type_info
 				tag = ir_emit_conv(proc, variant_ptr, t_type_info_complex_ptr);
 				break;
 
+			case Basic_quaternion128:
+			case Basic_quaternion256:
+				tag = ir_emit_conv(proc, variant_ptr, t_type_info_quaternion_ptr);
+				break;
+
 			case Basic_rawptr:
 				tag = ir_emit_conv(proc, variant_ptr, t_type_info_pointer_ptr);
 				break;
@@ -10039,9 +10723,9 @@ void ir_setup_type_info_data(irProcedure *proc) { // NOTE(bill): Setup type_info
 				irValue *is_packed       = ir_const_bool(t->Struct.is_packed);
 				irValue *is_raw_union    = ir_const_bool(t->Struct.is_raw_union);
 				irValue *is_custom_align = ir_const_bool(t->Struct.custom_align != 0);
-				ir_emit_store(proc, ir_emit_struct_ep(proc, tag, 4), is_packed);
-				ir_emit_store(proc, ir_emit_struct_ep(proc, tag, 5), is_raw_union);
-				ir_emit_store(proc, ir_emit_struct_ep(proc, tag, 6), is_custom_align);
+				ir_emit_store(proc, ir_emit_struct_ep(proc, tag, 5), is_packed);
+				ir_emit_store(proc, ir_emit_struct_ep(proc, tag, 6), is_raw_union);
+				ir_emit_store(proc, ir_emit_struct_ep(proc, tag, 7), is_custom_align);
 			}
 
 			isize count = t->Struct.fields.count;
@@ -10050,6 +10734,7 @@ void ir_setup_type_info_data(irProcedure *proc) { // NOTE(bill): Setup type_info
 				irValue *memory_names   = ir_type_info_member_names_offset  (proc, count);
 				irValue *memory_offsets = ir_type_info_member_offsets_offset(proc, count);
 				irValue *memory_usings  = ir_type_info_member_usings_offset (proc, count);
+				irValue *memory_tags    = ir_type_info_member_tags_offset   (proc, count);
 
 				type_set_offsets(t); // NOTE(bill): Just incase the offsets have not been set yet
 				for (isize source_index = 0; source_index < count; source_index++) {
@@ -10065,7 +10750,7 @@ void ir_setup_type_info_data(irProcedure *proc) { // NOTE(bill): Setup type_info
 					irValue *index     = ir_const_int(source_index);
 					irValue *type_info = ir_emit_ptr_offset(proc, memory_types,   index);
 					irValue *offset    = ir_emit_ptr_offset(proc, memory_offsets, index);
-					irValue *is_using  = ir_emit_ptr_offset(proc, memory_usings, index);
+					irValue *is_using  = ir_emit_ptr_offset(proc, memory_usings,  index);
 
 					ir_emit_store(proc, type_info, ir_type_info(proc, f->type));
 					if (f->token.string.len > 0) {
@@ -10074,6 +10759,15 @@ void ir_setup_type_info_data(irProcedure *proc) { // NOTE(bill): Setup type_info
 					}
 					ir_emit_store(proc, offset, ir_const_uintptr(foffset));
 					ir_emit_store(proc, is_using, ir_const_bool((f->flags&EntityFlag_Using) != 0));
+
+					if (t->Struct.tags.count > 0) {
+						String tag_string = t->Struct.tags[source_index];
+						if (tag_string.len > 0) {
+							irValue *tag_ptr = ir_emit_ptr_offset(proc, memory_tags, index);
+							ir_emit_store(proc, tag_ptr, ir_const_string(tag_string));
+						}
+					}
+
 				}
 
 				irValue *cv = ir_const_int(count);
@@ -10081,6 +10775,7 @@ void ir_setup_type_info_data(irProcedure *proc) { // NOTE(bill): Setup type_info
 				ir_fill_slice(proc, ir_emit_struct_ep(proc, tag, 1), memory_names,   cv);
 				ir_fill_slice(proc, ir_emit_struct_ep(proc, tag, 2), memory_offsets, cv);
 				ir_fill_slice(proc, ir_emit_struct_ep(proc, tag, 3), memory_usings,  cv);
+				ir_fill_slice(proc, ir_emit_struct_ep(proc, tag, 4), memory_tags,    cv);
 			}
 			break;
 		}
@@ -10482,12 +11177,14 @@ void ir_gen_tree(irGen *s) {
 		// main :: proc(argc: i32, argv: ^^u8) -> i32
 		String name = str_lit("main");
 
+#if 0
 		if (str_eq_ignore_case(cross_compile_target, str_lit("Essence"))) {
 			// This is a bit hacky,
 			// because this makes this function the first function run in the executable
 			// so it won't actually have the argc/argv arguments.
 			name = str_lit("ProgramEntry");
 		}
+#endif
 
 		Type *proc_params = alloc_type_tuple();
 		Type *proc_results = alloc_type_tuple();
diff --git a/src/ir_print.cpp b/src/ir_print.cpp
index b008fa682..d47dfc898 100644
--- a/src/ir_print.cpp
+++ b/src/ir_print.cpp
@@ -323,12 +323,15 @@ void ir_print_proc_results(irFileBuffer *f, irModule *m, Type *t) {
 
 
 void ir_print_proc_type_without_pointer(irFileBuffer *f, irModule *m, Type *t) {
+	set_procedure_abi_types(heap_allocator(), t);
+
 	i64 word_bits = 8*build_context.word_size;
 	t = base_type(t);
 	GB_ASSERT(is_type_proc(t));
 
 	isize param_count = t->Proc.param_count;
 	isize result_count = t->Proc.result_count;
+
 	ir_print_proc_results(f, m, t);
 	ir_write_string(f, str_lit(" ("));
 	if (t->Proc.return_by_pointer) {
@@ -418,20 +421,23 @@ void ir_print_type(irFileBuffer *f, irModule *m, Type *t, bool in_struct) {
 			}
 			return;
 
-		// case Basic_f16:    ir_write_str_lit(f, "half");              return;
-		case Basic_f32:    ir_write_str_lit(f, "float");                return;
-		case Basic_f64:    ir_write_str_lit(f, "double");               return;
+		// case Basic_f16:    ir_write_str_lit(f, "half");                 return;
+		case Basic_f32:    ir_write_str_lit(f, "float");                   return;
+		case Basic_f64:    ir_write_str_lit(f, "double");                  return;
+
+		// case Basic_complex32:  ir_write_str_lit(f, "%%..complex32");    return;
+		case Basic_complex64:  ir_write_str_lit(f, "%..complex64");        return;
+		case Basic_complex128: ir_write_str_lit(f, "%..complex128");       return;
 
-		// case Basic_complex32:  ir_write_str_lit(f, "%%..complex32"); return;
-		case Basic_complex64:  ir_write_str_lit(f, "%..complex64");     return;
-		case Basic_complex128: ir_write_str_lit(f, "%..complex128");    return;
+		case Basic_quaternion128: ir_write_str_lit(f, "%..quaternion128"); return;
+		case Basic_quaternion256: ir_write_str_lit(f, "%..quaternion256"); return;
 
-		case Basic_any:     ir_write_str_lit(f, "%..any");              return;
-		case Basic_rawptr:  ir_write_str_lit(f, "%..rawptr");           return;
-		case Basic_string:  ir_write_str_lit(f, "%..string");           return;
-		case Basic_cstring: ir_write_str_lit(f, "i8*");                 return;
+		case Basic_any:     ir_write_str_lit(f, "%..any");                 return;
+		case Basic_rawptr:  ir_write_str_lit(f, "%..rawptr");              return;
+		case Basic_string:  ir_write_str_lit(f, "%..string");              return;
+		case Basic_cstring: ir_write_str_lit(f, "i8*");                    return;
 
-		case Basic_typeid:  ir_write_str_lit(f, "%..typeid");           return;
+		case Basic_typeid:  ir_write_str_lit(f, "%..typeid");              return;
 		}
 		break;
 
@@ -767,15 +773,17 @@ void ir_print_exact_value(irFileBuffer *f, irModule *m, ExactValue value, Type *
 	case ExactValue_Float: {
 		GB_ASSERT_MSG(is_type_float(type), "%s", type_to_string(type));
 		type = core_type(type);
-		u64 u = bit_cast<u64>(value.value_float);
+		u64 u_64 = bit_cast<u64>(value.value_float);
+		u32 u_32 = bit_cast<u32>(cast(f32)value.value_float);
+	#if 0
 		switch (type->Basic.kind) {
 		case Basic_f32:
 			// IMPORTANT NOTE(bill): LLVM requires all floating point constants to be
 			// a 64 bit number if bits_of(float type) <= 64.
 			// https://groups.google.com/forum/#!topic/llvm-dev/IlqV3TbSk6M
-			// 64 bit mantissa: 52 bits
-			// 32 bit mantissa: 23 bits
-			// 16 bit mantissa: 10 bits
+			// 64 bit mantissa: 52 bits ==> 52-52 ==  0
+			// 32 bit mantissa: 23 bits ==> 52-23 == 29
+			// 16 bit mantissa: 10 bits ==> 52=10 == 42
 			// 29 == 52-23
 			u >>= 29;
 			u <<= 29;
@@ -792,9 +800,24 @@ void ir_print_exact_value(irFileBuffer *f, irModule *m, ExactValue value, Type *
 			ir_fprintf(f, "0x%016llx", u);
 			break;
 		}
+	#else
+		switch (type->Basic.kind) {
+		case Basic_f32: {
+			ir_fprintf(f, "bitcast (i32 %u to float)", u_32);
+			break;
+		}
+		case Basic_f64:
+			ir_fprintf(f, "0x%016llx", u_64);
+			break;
+		default:
+			ir_fprintf(f, "0x%016llx", u_64);
+			break;
+		}
+	#endif
 		break;
 	}
 	case ExactValue_Complex: {
+		// xy/ri format
 		type = core_type(type);
 		GB_ASSERT_MSG(is_type_complex(type), "%s", type_to_string(type));
 		Type *ft = base_complex_elem_type(type);
@@ -807,6 +830,26 @@ void ir_print_exact_value(irFileBuffer *f, irModule *m, ExactValue value, Type *
 		ir_write_byte(f, '}');
 		break;
 	}
+
+	case ExactValue_Quaternion: {
+		// xyzw/ijkr format
+		type = core_type(type);
+		GB_ASSERT_MSG(is_type_quaternion(type), "%s", type_to_string(type));
+		Type *ft = base_complex_elem_type(type);
+		ir_write_byte(f, ' ');
+		ir_write_byte(f, '{');
+		ir_print_type(f, m, ft); ir_write_byte(f, ' ');
+		ir_print_exact_value(f, m, exact_value_float(value.value_quaternion.imag), ft);
+		ir_write_str_lit(f, ", "); ir_print_type(f, m, ft); ir_write_byte(f, ' ');
+		ir_print_exact_value(f, m, exact_value_float(value.value_quaternion.jmag), ft);
+		ir_write_str_lit(f, ", "); ir_print_type(f, m, ft); ir_write_byte(f, ' ');
+		ir_print_exact_value(f, m, exact_value_float(value.value_quaternion.kmag), ft);
+		ir_write_str_lit(f, ", "); ir_print_type(f, m, ft); ir_write_byte(f, ' ');
+		ir_print_exact_value(f, m, exact_value_float(value.value_quaternion.real), ft);
+		ir_write_byte(f, '}');
+		break;
+	}
+
 	case ExactValue_Pointer:
 		if (value.value_pointer == 0) {
 			if (is_type_typeid(type)) {
@@ -836,22 +879,86 @@ void ir_print_exact_value(irFileBuffer *f, irModule *m, ExactValue value, Type *
 				ir_write_str_lit(f, "zeroinitializer");
 				break;
 			}
-			GB_ASSERT_MSG(elem_count == type->Array.count, "%td != %td", elem_count, type->Array.count);
+			if (cl->elems[0]->kind == Ast_FieldValue) {
+				// TODO(bill): This is O(N*M) and will be quite slow; it should probably be sorted before hand
+				ir_write_byte(f, '[');
+				for (i64 i = 0; i < type->Array.count; i++) {
+					if (i > 0) ir_write_str_lit(f, ", ");
+
+					bool found = false;
+
+					for (isize j = 0; j < elem_count; j++) {
+						Ast *elem = cl->elems[j];
+						ast_node(fv, FieldValue, elem);
+						if (is_ast_range(fv->field)) {
+							ast_node(ie, BinaryExpr, fv->field);
+							TypeAndValue lo_tav = ie->left->tav;
+							TypeAndValue hi_tav = ie->right->tav;
+							GB_ASSERT(lo_tav.mode == Addressing_Constant);
+							GB_ASSERT(hi_tav.mode == Addressing_Constant);
+
+							TokenKind op = ie->op.kind;
+							i64 lo = exact_value_to_i64(lo_tav.value);
+							i64 hi = exact_value_to_i64(hi_tav.value);
+							if (op == Token_Ellipsis) {
+								hi += 1;
+							}
+							if (lo == i) {
+								TypeAndValue tav = fv->value->tav;
+								if (tav.mode != Addressing_Constant) {
+									break;
+								}
+								for (i64 k = lo; k < hi; k++) {
+									if (k > lo) ir_write_str_lit(f, ", ");
+
+									ir_print_compound_element(f, m, tav.value, elem_type);
+								}
+
+								found = true;
+								i += (hi-lo-1);
+								break;
+							}
+						} else {
+							TypeAndValue index_tav = fv->field->tav;
+							GB_ASSERT(index_tav.mode == Addressing_Constant);
+							i64 index = exact_value_to_i64(index_tav.value);
+							if (index == i) {
+								TypeAndValue tav = fv->value->tav;
+								if (tav.mode != Addressing_Constant) {
+									break;
+								}
+								ir_print_compound_element(f, m, tav.value, elem_type);
+								found = true;
+								break;
+							}
+						}
+					}
 
-			ir_write_byte(f, '[');
+					if (!found) {
+						ir_print_type(f, m, elem_type);
+						ir_write_byte(f, ' ');
+						ir_write_str_lit(f, "zeroinitializer");
+					}
+				}
+				ir_write_byte(f, ']');
+			} else {
+				GB_ASSERT_MSG(elem_count == type->Array.count, "%td != %td", elem_count, type->Array.count);
 
-			for (isize i = 0; i < elem_count; i++) {
-				if (i > 0) ir_write_str_lit(f, ", ");
-				TypeAndValue tav = cl->elems[i]->tav;
-				GB_ASSERT(tav.mode != Addressing_Invalid);
-				ir_print_compound_element(f, m, tav.value, elem_type);
-			}
-			for (isize i = elem_count; i < type->Array.count; i++) {
-				if (i >= elem_count) ir_write_str_lit(f, ", ");
-				ir_print_compound_element(f, m, empty_exact_value, elem_type);
-			}
+				ir_write_byte(f, '[');
 
-			ir_write_byte(f, ']');
+				for (isize i = 0; i < elem_count; i++) {
+					if (i > 0) ir_write_str_lit(f, ", ");
+					TypeAndValue tav = cl->elems[i]->tav;
+					GB_ASSERT(tav.mode != Addressing_Invalid);
+					ir_print_compound_element(f, m, tav.value, elem_type);
+				}
+				for (isize i = elem_count; i < type->Array.count; i++) {
+					if (i >= elem_count) ir_write_str_lit(f, ", ");
+					ir_print_compound_element(f, m, empty_exact_value, elem_type);
+				}
+
+				ir_write_byte(f, ']');
+			}
 		} else if (is_type_simd_vector(type)) {
 			ast_node(cl, CompoundLit, value.value_compound);
 
@@ -927,7 +1034,8 @@ void ir_print_exact_value(irFileBuffer *f, irModule *m, ExactValue value, Type *
 			if (type->Struct.is_packed) ir_write_byte(f, '<');
 			ir_write_byte(f, '{');
 			if (type->Struct.custom_align > 0) {
-				ir_fprintf(f, "[0 x <%lld x i8>] zeroinitializer", cast(i64)type->Struct.custom_align);
+				ir_print_alignment_prefix_hack(f, cast(i64)type->Struct.custom_align);
+				ir_write_str_lit(f, " zeroinitializer");
 				if (value_count > 0) {
 					ir_write_string(f, str_lit(", "));
 				}
@@ -1089,7 +1197,11 @@ void ir_print_value(irFileBuffer *f, irModule *m, irValue *value, Type *type_hin
 		break;
 	}
 	case irValue_Param:
-		ir_print_encoded_local(f, value->Param.entity->token.string);
+		if (value->Param.index >= 0) {
+			ir_fprintf(f, "%%_.%d", value->Param.index);
+		} else {
+			ir_print_encoded_local(f, value->Param.entity->token.string);
+		}
 		break;
 	case irValue_SourceCodeLocation: {
 		irValue *file      = value->SourceCodeLocation.file;
@@ -1124,7 +1236,8 @@ void ir_print_calling_convention(irFileBuffer *f, irModule *m, ProcCallingConven
 	switch (cc) {
 	case ProcCC_Odin:        ir_write_str_lit(f, "");       break;
 	case ProcCC_Contextless: ir_write_str_lit(f, "");       break;
-	case ProcCC_CDecl:       ir_write_str_lit(f, "ccc ");   break;
+	// case ProcCC_CDecl:       ir_write_str_lit(f, "ccc ");   break;
+	case ProcCC_CDecl:       ir_write_str_lit(f, "");   break;
 	case ProcCC_StdCall:     ir_write_str_lit(f, "cc 64 "); break;
 	case ProcCC_FastCall:    ir_write_str_lit(f, "cc 65 "); break;
 	case ProcCC_None:        ir_write_str_lit(f, "");       break;
@@ -1134,8 +1247,8 @@ void ir_print_calling_convention(irFileBuffer *f, irModule *m, ProcCallingConven
 
 void ir_print_context_parameter_prefix(irFileBuffer *f, irModule *m) {
 	ir_print_type(f, m, t_context_ptr);
-	ir_write_str_lit(f, " noalias nonnull nocapture inreg ");
-	// ir_write_str_lit(f, " noalias nonnull nocapture ");
+	// ir_write_str_lit(f, " noalias nonnull nocapture inreg ");
+	ir_write_str_lit(f, " noalias nonnull nocapture ");
 }
 
 void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
@@ -1186,6 +1299,7 @@ void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
 		ir_write_str_lit(f, ", ");
 		ir_print_type(f, m, type);
 		ir_fprintf(f, "* %%%d, align 1", instr->ZeroInit.address->index);
+		// ir_fprintf(f, "* %%%d", instr->ZeroInit.address->index);
 		break;
 	}
 
@@ -1888,11 +2002,11 @@ void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
 					if (e->flags&EntityFlag_NoAlias) {
 						ir_write_str_lit(f, " noalias");
 					}
+					if (e->flags&EntityFlag_ImplicitReference) {
+						ir_write_str_lit(f, " nonnull dereferenceable");
+					}
 					ir_write_byte(f, ' ');
 					irValue *arg = call->args[i];
-					if (is_type_boolean(t)) {
-
-					}
 					ir_print_value(f, m, arg, t);
 					param_index++;
 				}
@@ -1907,24 +2021,43 @@ void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
 					param_index++;
 				}
 			} else {
-				GB_ASSERT(call->args.count == params->variables.count);
+				// GB_ASSERT(call->args.count == params->variables.count);
+				isize arg_index = 0;
 				for_array(i, params->variables) {
 					Entity *e = params->variables[i];
 					GB_ASSERT(e != nullptr);
-					if (e->kind != Entity_Variable) continue;
+					if (e->kind != Entity_Variable) {
+						arg_index++;
+						continue;
+					}
 
 					if (param_index > 0) ir_write_str_lit(f, ", ");
 
-					irValue *arg = call->args[i];
 					Type *t = proc_type->Proc.abi_compat_params[i];
-
-					ir_print_type(f, m, t);
-					if (e->flags&EntityFlag_NoAlias) {
-						ir_write_str_lit(f, " noalias");
+					if (is_type_tuple(t)) {
+						for_array(j, t->Tuple.variables) {
+							if (j > 0) ir_write_str_lit(f, ", ");
+
+							irValue *arg = call->args[arg_index++];
+
+							ir_print_type(f, m, t->Tuple.variables[j]->type);
+							if (e->flags&EntityFlag_NoAlias) {
+								ir_write_str_lit(f, " noalias");
+							}
+							ir_write_byte(f, ' ');
+							ir_print_value(f, m, arg, t);
+							param_index++;
+						}
+					} else {
+						irValue *arg = call->args[arg_index++];
+						ir_print_type(f, m, t);
+						if (e->flags&EntityFlag_NoAlias) {
+							ir_write_str_lit(f, " noalias");
+						}
+						ir_write_byte(f, ' ');
+						ir_print_value(f, m, arg, t);
+						param_index++;
 					}
-					ir_write_byte(f, ' ');
-					ir_print_value(f, m, arg, t);
-					param_index++;
 				}
 			}
 		}
@@ -1995,6 +2128,8 @@ void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
 
 
 void ir_print_proc(irFileBuffer *f, irModule *m, irProcedure *proc) {
+	set_procedure_abi_types(heap_allocator(), proc->type);
+
 	if (proc->body == nullptr) {
 		ir_write_str_lit(f, "declare ");
 		// if (proc->tags & ProcTag_dll_import) {
@@ -2043,7 +2178,8 @@ void ir_print_proc(irFileBuffer *f, irModule *m, irProcedure *proc) {
 
 	if (param_count > 0) {
 		TypeTuple *params = &proc_type->params->Tuple;
-		for (isize i = 0; i < param_count; i++) {
+		isize parameter_index = 0;
+		for (isize i = 0; i < param_count; i++, parameter_index++) {
 			Entity *e = params->variables[i];
 			Type *original_type = e->type;
 			Type *abi_type = proc_type->abi_compat_params[i];
@@ -2053,16 +2189,29 @@ void ir_print_proc(irFileBuffer *f, irModule *m, irProcedure *proc) {
 			if (i+1 == params->variables.count && proc_type->c_vararg) {
 				ir_write_str_lit(f, " ...");
 			} else {
-				ir_print_type(f, m, abi_type);
-				if (e->flags&EntityFlag_NoAlias) {
-					ir_write_str_lit(f, " noalias");
-				}
-				if (proc->body != nullptr) {
-					if (e->token.string != "" && !is_blank_ident(e->token)) {
-						ir_write_byte(f, ' ');
-						ir_print_encoded_local(f, e->token.string);
-					} else {
-						ir_fprintf(f, " %%_.param_%td", i);
+				if (is_type_tuple(abi_type)) {
+					for_array(j, abi_type->Tuple.variables) {
+						if (j > 0) ir_write_string(f, str_lit(", "));
+
+						Type *tft = abi_type->Tuple.variables[j]->type;
+						ir_print_type(f, m, tft);
+						if (e->flags&EntityFlag_NoAlias) {
+							ir_write_str_lit(f, " noalias");
+						}
+
+						if (proc->body != nullptr) {
+							ir_fprintf(f, " %%_.%td", parameter_index+j);
+						}
+					}
+					parameter_index += abi_type->Tuple.variables.count-1;
+					param_index += abi_type->Tuple.variables.count-1;
+				} else {
+					ir_print_type(f, m, abi_type);
+					if (e->flags&EntityFlag_NoAlias) {
+						ir_write_str_lit(f, " noalias");
+					}
+					if (proc->body != nullptr) {
+						ir_fprintf(f, " %%_.%td", parameter_index);
 					}
 				}
 			}
@@ -2176,6 +2325,22 @@ void ir_print_type_name(irFileBuffer *f, irModule *m, irValue *v) {
 	ir_write_byte(f, '\n');
 }
 
+bool ir_print_global_type_allowed(Type *t) {
+	if (t == nullptr) {
+		return true;
+	}
+	t = core_type(t);
+	switch (t->kind) {
+	case Type_DynamicArray:
+	case Type_Map:
+	case Type_Union:
+	case Type_BitField:
+		return false;
+	}
+
+	return true;
+}
+
 void print_llvm_ir(irGen *ir) {
 	irModule *m = &ir->module;
 
@@ -2184,9 +2349,11 @@ void print_llvm_ir(irGen *ir) {
 	defer (ir_file_buffer_destroy(f));
 
 	i32 word_bits = cast(i32)(8*build_context.word_size);
-	if (build_context.ODIN_OS == "osx" || build_context.ODIN_OS == "macos") {
+	if (build_context.ODIN_OS == "darwin") {
 		GB_ASSERT(word_bits == 64);
-		ir_write_str_lit(f, "target triple = \"x86_64-apple-macosx10.8\"\n\n");
+		ir_write_str_lit(f, "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n");
+		ir_write_str_lit(f, "target triple = \"x86_64-apple-macosx10.8\"\n");
+		ir_write_str_lit(f, "\n");
 	} else if (build_context.ODIN_OS == "windows") {
 		ir_fprintf(f, "target triple = \"x86%s-pc-windows-msvc\"\n\n", word_bits == 64 ? "_64" : "");
 		if (word_bits == 64 && build_context.metrics.arch == TargetArch_amd64) {
@@ -2210,6 +2377,13 @@ void print_llvm_ir(irGen *ir) {
 	ir_print_encoded_local(f, str_lit("..complex128"));
 	ir_write_str_lit(f, " = type {double, double} ; Basic_complex128\n");
 
+	ir_print_encoded_local(f, str_lit("..quaternion64"));
+	ir_write_str_lit(f, " = type {half, half, half, half} ; Basic_quaternion64\n");
+	ir_print_encoded_local(f, str_lit("..quaternion128"));
+	ir_write_str_lit(f, " = type {float, float, float, float} ; Basic_quaternion128\n");
+	ir_print_encoded_local(f, str_lit("..quaternion256"));
+	ir_write_str_lit(f, " = type {double, double, double, double} ; Basic_quaternion256\n");
+
 	ir_print_encoded_local(f, str_lit("..typeid"));
 	ir_write_str_lit(f, " = type ");
 	ir_print_type(f, m, t_uintptr);
@@ -2339,7 +2513,7 @@ void print_llvm_ir(irGen *ir) {
 		ir_print_type(f, m, g->entity->type);
 		ir_write_byte(f, ' ');
 		if (!g->is_foreign) {
-			if (g->value != nullptr) {
+			if (g->value != nullptr && ir_print_global_type_allowed(g->entity->type)) {
 				ir_print_value(f, m, g->value, g->entity->type);
 			} else {
 				ir_write_string(f, str_lit("zeroinitializer"));
@@ -2383,11 +2557,13 @@ void print_llvm_ir(irGen *ir) {
 
 		for_array(di_index, m->debug_info.entries) {
 			irDebugInfo *di = m->debug_info.entries[di_index].value;
+			GB_ASSERT_MSG(di != nullptr, "Invalid irDebugInfo");
 			ir_fprintf(f, "!%d = ", di->id);
-
 			switch (di->kind) {
 			case irDebugInfo_CompileUnit: {
-				irDebugInfo *file = *map_get(&m->debug_info, hash_pointer(di->CompileUnit.file));
+				irDebugInfo **found = map_get(&m->debug_info, hash_pointer(di->CompileUnit.file));
+				GB_ASSERT_MSG(found != nullptr, "Missing debug info for: %.*s\n", LIT(di->CompileUnit.file->fullpath));
+				irDebugInfo *file = *found;
 				ir_fprintf(f,
 				            "distinct !DICompileUnit("
 				              "language: DW_LANG_C_plus_plus" // Is this good enough?
diff --git a/src/main.cpp b/src/main.cpp
index 05fa6c366..acb580ca2 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -75,7 +75,7 @@ i32 system_exec_command_line_app(char *name, char *fmt, ...) {
 	va_end(va);
 	cmd = make_string(cast(u8 *)&cmd_line, cmd_len-1);
 
-	//printf("do: %s\n", cmd_line);
+	// printf("do: %s\n", cmd_line);
 	exit_code = system(&cmd_line[0]);
 
 	// pid_t pid = fork();
@@ -160,8 +160,9 @@ void usage(String argv0) {
 	print_usage_line(0, "Usage:");
 	print_usage_line(1, "%.*s command [arguments]", LIT(argv0));
 	print_usage_line(0, "Commands:");
-	print_usage_line(1, "build     compile .odin file as executable");
-	print_usage_line(1, "run       compile and run .odin file");
+	print_usage_line(1, "build     compile .odin file, or directory of .odin files, as an executable.");
+	print_usage_line(1, "          one must contain the program's entry point, all must be in the same package.");
+	print_usage_line(1, "run       same as 'build', but also then runs the newly compiled executable.");
 	print_usage_line(1, "check     parse and type check .odin file");
 	print_usage_line(1, "query     parse, type check, and output a .json file containing information about the program");
 	print_usage_line(1, "docs      generate documentation for a .odin file");
@@ -210,9 +211,8 @@ enum BuildFlagKind {
 	BuildFlag_Collection,
 	BuildFlag_Define,
 	BuildFlag_BuildMode,
+	BuildFlag_Target,
 	BuildFlag_Debug,
-	BuildFlag_CrossCompile,
-	BuildFlag_CrossLibDir,
 	BuildFlag_NoBoundsCheck,
 	BuildFlag_NoCRT,
 	BuildFlag_UseLLD,
@@ -298,9 +298,8 @@ bool parse_build_flags(Array<String> args) {
 	add_flag(&build_flags, BuildFlag_Collection,        str_lit("collection"),      BuildFlagParam_String);
 	add_flag(&build_flags, BuildFlag_Define,            str_lit("define"),          BuildFlagParam_String);
 	add_flag(&build_flags, BuildFlag_BuildMode,         str_lit("build-mode"),      BuildFlagParam_String);
+	add_flag(&build_flags, BuildFlag_Target,            str_lit("target"),          BuildFlagParam_String);
 	add_flag(&build_flags, BuildFlag_Debug,             str_lit("debug"),           BuildFlagParam_None);
-	add_flag(&build_flags, BuildFlag_CrossCompile,      str_lit("cross-compile"),   BuildFlagParam_String);
-	add_flag(&build_flags, BuildFlag_CrossLibDir,       str_lit("cross-lib-dir"),   BuildFlagParam_String);
 	add_flag(&build_flags, BuildFlag_NoBoundsCheck,     str_lit("no-bounds-check"), BuildFlagParam_None);
 	add_flag(&build_flags, BuildFlag_NoCRT,             str_lit("no-crt"),          BuildFlagParam_None);
 	add_flag(&build_flags, BuildFlag_UseLLD,            str_lit("lld"),             BuildFlagParam_None);
@@ -447,7 +446,7 @@ bool parse_build_flags(Array<String> args) {
 										path = substring(path, 0, string_extension_position(path));
 									}
 								#endif
-								build_context.out_filepath = path;
+								build_context.out_filepath = path_to_full_path(heap_allocator(), path);
 							} else {
 								gb_printf_err("Invalid -out path, got %.*s\n", LIT(path));
 								bad_flags = true;
@@ -478,33 +477,6 @@ bool parse_build_flags(Array<String> args) {
 							build_context.keep_temp_files = true;
 							break;
 
-						case BuildFlag_CrossCompile: {
-							GB_ASSERT(value.kind == ExactValue_String);
-							cross_compile_target = value.value_string;
-						#if defined(GB_SYSTEM_UNIX) && defined(GB_ARCH_64_BIT)
-							if (str_eq_ignore_case(cross_compile_target, str_lit("Essence"))) {
-
-							} else
-						#endif
-							{
-								gb_printf_err("Unsupported cross compilation target '%.*s'\n", LIT(cross_compile_target));
-								gb_printf_err("Currently supported targets: Essence (from 64-bit Unixes only)\n");
-								bad_flags = true;
-							}
-							break;
-						}
-
-						case BuildFlag_CrossLibDir: {
-							GB_ASSERT(value.kind == ExactValue_String);
-							if (cross_compile_lib_dir.len) {
-								gb_printf_err("Multiple cross compilation library directories\n");
-								bad_flags = true;
-							} else {
-								cross_compile_lib_dir = concatenate_strings(heap_allocator(), str_lit("-L"), value.value_string);
-							}
-							break;
-						}
-
 						case BuildFlag_Collection: {
 							GB_ASSERT(value.kind == ExactValue_String);
 							String str = value.value_string;
@@ -623,7 +595,25 @@ bool parse_build_flags(Array<String> args) {
 							break;
 						}
 
+						case BuildFlag_Target: {
+							String str = value.value_string;
+							bool found = false;
+
+							for (int i = 0; i < sizeof(named_targets) / sizeof(named_targets[0]); i++) {
+								if (str_eq_ignore_case(str, named_targets[i].name)) {
+									found = true;
+									selected_target_metrics = named_targets + i;
+									break;
+								}
+							}
+
+							if (!found) {
+								gb_printf_err("Unknown target '%.*s'\n", LIT(str));
+								bad_flags = true;
+							}
 
+							break;
+						}
 
 						case BuildFlag_BuildMode: {
 							GB_ASSERT(value.kind == ExactValue_String);
@@ -635,7 +625,7 @@ bool parse_build_flags(Array<String> args) {
 								break;
 							}
 
-							if (str == "dll") {
+							if (str == "dll" || str == "shared") {
 								build_context.is_dll = true;
 							} else if (str == "exe") {
 								build_context.is_dll = false;
@@ -889,8 +879,8 @@ i32 exec_llvm_opt(String output_base) {
 }
 
 i32 exec_llvm_llc(String output_base) {
-#if defined(GB_SYSTEM_WINDOWS)
 	// For more arguments: http://llvm.org/docs/CommandGuide/llc.html
+#if defined(GB_SYSTEM_WINDOWS)
 	return system_exec_command_line_app("llvm-llc",
 		"\"%.*sbin\\llc\" \"%.*s.bc\" -filetype=obj -O%d "
 		"-o \"%.*s.obj\" "
@@ -903,21 +893,19 @@ i32 exec_llvm_llc(String output_base) {
 		LIT(build_context.llc_flags));
 #else
 	// NOTE(zangent): Linux / Unix is unfinished and not tested very well.
-	// For more arguments: http://llvm.org/docs/CommandGuide/llc.html
 	return system_exec_command_line_app("llc",
 		"llc \"%.*s.bc\" -filetype=obj -relocation-model=pic -O%d "
 		"%.*s "
-		"%s"
-		"",
+		"%s%.*s",
 		LIT(output_base),
 		build_context.optimization_level,
 		LIT(build_context.llc_flags),
-		str_eq_ignore_case(cross_compile_target, str_lit("Essence")) ? "-mtriple=x86_64-pc-none-elf" : "");
+		build_context.cross_compiling ? "-mtriple=" : "",
+		(int) (build_context.cross_compiling ? build_context.target_triplet.len : 0),
+		build_context.target_triplet.text);
 #endif
 }
 
-
-
 int main(int arg_count, char **arg_ptr) {
 	if (arg_count < 2) {
 		usage(make_string_c(arg_ptr[0]));
@@ -1026,7 +1014,7 @@ int main(int arg_count, char **arg_ptr) {
 	}
 
 
-	init_build_context();
+	init_build_context(selected_target_metrics ? selected_target_metrics->metrics : nullptr);
 	if (build_context.word_size == 4) {
 		print_usage_line(0, "%s 32-bit is not yet supported", args[0]);
 		return 1;
@@ -1121,6 +1109,17 @@ int main(int arg_count, char **arg_ptr) {
 		return exit_code;
 	}
 
+	if (build_context.cross_compiling) {
+		if (0) {
+#ifdef GB_SYSTEM_UNIX
+		} else if (selected_target_metrics->metrics == &target_essence_amd64) {
+			system_exec_command_line_app("linker", "x86_64-essence-gcc \"%.*s.o\" -o \"%.*s\" %.*s",
+					LIT(output_base), LIT(output_base), LIT(build_context.link_flags));
+#endif
+		} else {
+			gb_printf_err("Don't know how to cross compile to selected target.\n");
+		}
+	} else {
 	#if defined(GB_SYSTEM_WINDOWS)
 		timings_start_section(&timings, str_lit("msvc-link"));
 
@@ -1219,7 +1218,7 @@ int main(int arg_count, char **arg_ptr) {
 		remove_temp_files(output_base);
 
 		if (run_output) {
-			system_exec_command_line_app("odin run", "%.*s.exe %.*s", LIT(output_base), LIT(run_args_string));
+			return system_exec_command_line_app("odin run", "%.*s.exe %.*s", LIT(output_base), LIT(run_args_string));
 		}
 	#else
 		timings_start_section(&timings, str_lit("ld-link"));
@@ -1241,15 +1240,17 @@ int main(int arg_count, char **arg_ptr) {
 			//   This allows you to specify '-f' in a #foreign_system_library,
 			//   without having to implement any new syntax specifically for MacOS.
 			#if defined(GB_SYSTEM_OSX)
-				if (lib.len > 2 && lib[0] == '-' && lib[1] == 'f') {
+				if (string_ends_with(lib, str_lit(".framework"))) {
 					// framework thingie
-					lib_str = gb_string_append_fmt(lib_str, " -framework %.*s ", (int)(lib.len) - 2, lib.text + 2);
+					String lib_name = lib;
+					lib_name = remove_extension_from_path(lib_name);
+					lib_str = gb_string_append_fmt(lib_str, " -framework %.*s ", LIT(lib_name));
 				} else if (string_ends_with(lib, str_lit(".a"))) {
 					// static libs, absolute full path relative to the file in which the lib was imported from
 					lib_str = gb_string_append_fmt(lib_str, " %.*s ", LIT(lib));
 				} else if (string_ends_with(lib, str_lit(".dylib"))) {
-					// dynamic lib, relative path to executable
-					lib_str = gb_string_append_fmt(lib_str, " -l:%s/%.*s ", cwd, LIT(lib));
+					// dynamic lib
+					lib_str = gb_string_append_fmt(lib_str, " -l%.*s ", LIT(lib));
 				} else {
 					// dynamic or static system lib, just link regularly searching system library paths
 					lib_str = gb_string_append_fmt(lib_str, " -l%.*s ", LIT(lib));
@@ -1309,11 +1310,7 @@ int main(int arg_count, char **arg_ptr) {
 			//   It probably has to do with including the entire CRT, but
 			//   that's quite a complicated issue to solve while remaining distro-agnostic.
 			//   Clang can figure out linker flags for us, and that's good enough _for now_.
-			if (str_eq_ignore_case(cross_compile_target, str_lit("Essence"))) {
-				linker = "x86_64-elf-gcc -T core/sys/essence_linker_userland64.ld -ffreestanding -nostdlib -lgcc -g -z max-page-size=0x1000 -Wno-unused-command-line-argument";
-			} else {
-				linker = "clang -Wno-unused-command-line-argument";
-			}
+			linker = "clang -Wno-unused-command-line-argument";
 		#endif
 
 		exit_code = system_exec_command_line_app("ld-link",
@@ -1321,7 +1318,6 @@ int main(int arg_count, char **arg_ptr) {
 			" %s "
 			" %.*s "
 			" %s "
-			" %.*s "
 			#if defined(GB_SYSTEM_OSX)
 				// This sets a requirement of Mountain Lion and up, but the compiler doesn't work without this limit.
 				// NOTE: If you change this (although this minimum is as low as you can go with Odin working)
@@ -1332,11 +1328,9 @@ int main(int arg_count, char **arg_ptr) {
 			#endif
 			, linker, LIT(output_base), LIT(output_base), LIT(output_ext),
 			lib_str,
-			str_eq_ignore_case(cross_compile_target, str_lit("Essence")) ? "-lfreetype -lglue" : "-lc -lm",
+			"-lc -lm",
 			LIT(build_context.link_flags),
-			link_settings,
-			LIT(cross_compile_lib_dir)
-			);
+			link_settings);
 		if (exit_code != 0) {
 			return exit_code;
 		}
@@ -1366,9 +1360,10 @@ int main(int arg_count, char **arg_ptr) {
 			//NOTE(thebirk): This whole thing is a little leaky
 			String complete_path = concatenate_strings(heap_allocator(), output_base, output_ext);
 			complete_path = path_to_full_path(heap_allocator(), complete_path);
-			system_exec_command_line_app("odin run", "\"%.*s\" %.*s", LIT(complete_path), LIT(run_args_string));
+			return system_exec_command_line_app("odin run", "\"%.*s\" %.*s", LIT(complete_path), LIT(run_args_string));
 		}
 	#endif
+	}
 
 	return 0;
 }
diff --git a/src/parser.cpp b/src/parser.cpp
index a377b773c..10aa10119 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -51,6 +51,7 @@ Token ast_token(Ast *node) {
 	case Ast_ReturnStmt:         return node->ReturnStmt.token;
 	case Ast_ForStmt:            return node->ForStmt.token;
 	case Ast_RangeStmt:          return node->RangeStmt.token;
+	case Ast_InlineRangeStmt:    return node->InlineRangeStmt.inline_token;
 	case Ast_CaseClause:         return node->CaseClause.token;
 	case Ast_SwitchStmt:         return node->SwitchStmt.token;
 	case Ast_TypeSwitchStmt:     return node->TypeSwitchStmt.token;
@@ -143,6 +144,7 @@ Ast *clone_ast(Ast *node) {
 	case Ast_ProcLit:
 		n->ProcLit.type = clone_ast(n->ProcLit.type);
 		n->ProcLit.body = clone_ast(n->ProcLit.body);
+		n->ProcLit.where_clauses = clone_ast_array(n->ProcLit.where_clauses);
 		break;
 	case Ast_CompoundLit:
 		n->CompoundLit.type  = clone_ast(n->CompoundLit.type);
@@ -257,6 +259,12 @@ Ast *clone_ast(Ast *node) {
 		n->RangeStmt.expr  = clone_ast(n->RangeStmt.expr);
 		n->RangeStmt.body  = clone_ast(n->RangeStmt.body);
 		break;
+	case Ast_InlineRangeStmt:
+		n->InlineRangeStmt.val0  = clone_ast(n->InlineRangeStmt.val0);
+		n->InlineRangeStmt.val1  = clone_ast(n->InlineRangeStmt.val1);
+		n->InlineRangeStmt.expr  = clone_ast(n->InlineRangeStmt.expr);
+		n->InlineRangeStmt.body  = clone_ast(n->InlineRangeStmt.body);
+		break;
 	case Ast_CaseClause:
 		n->CaseClause.list  = clone_ast_array(n->CaseClause.list);
 		n->CaseClause.stmts = clone_ast_array(n->CaseClause.stmts);
@@ -341,10 +349,12 @@ Ast *clone_ast(Ast *node) {
 		n->StructType.fields = clone_ast_array(n->StructType.fields);
 		n->StructType.polymorphic_params = clone_ast(n->StructType.polymorphic_params);
 		n->StructType.align  = clone_ast(n->StructType.align);
+		n->StructType.where_clauses  = clone_ast_array(n->StructType.where_clauses);
 		break;
 	case Ast_UnionType:
 		n->UnionType.variants = clone_ast_array(n->UnionType.variants);
 		n->UnionType.polymorphic_params = clone_ast(n->UnionType.polymorphic_params);
+		n->UnionType.where_clauses = clone_ast_array(n->UnionType.where_clauses);
 		break;
 	case Ast_EnumType:
 		n->EnumType.base_type = clone_ast(n->EnumType.base_type);
@@ -417,7 +427,7 @@ void syntax_error(Ast *node, char *fmt, ...) {
 
 bool ast_node_expect(Ast *node, AstKind kind) {
 	if (node->kind != kind) {
-		error(node, "Expected %.*s, got %.*s", LIT(ast_strings[kind]), LIT(ast_strings[node->kind]));
+		syntax_error(node, "Expected %.*s, got %.*s", LIT(ast_strings[kind]), LIT(ast_strings[node->kind]));
 		return false;
 	}
 	return true;
@@ -578,6 +588,7 @@ Ast *ast_undef(AstFile *f, Token token) {
 Ast *ast_basic_lit(AstFile *f, Token basic_lit) {
 	Ast *result = alloc_ast_node(f, Ast_BasicLit);
 	result->BasicLit.token = basic_lit;
+	result->BasicLit.value = exact_value_from_basic_literal(basic_lit);
 	return result;
 }
 
@@ -605,11 +616,13 @@ Ast *ast_proc_group(AstFile *f, Token token, Token open, Token close, Array<Ast
 	return result;
 }
 
-Ast *ast_proc_lit(AstFile *f, Ast *type, Ast *body, u64 tags) {
+Ast *ast_proc_lit(AstFile *f, Ast *type, Ast *body, u64 tags, Token where_token, Array<Ast *> const &where_clauses) {
 	Ast *result = alloc_ast_node(f, Ast_ProcLit);
 	result->ProcLit.type = type;
 	result->ProcLit.body = body;
 	result->ProcLit.tags = tags;
+	result->ProcLit.where_token = where_token;
+	result->ProcLit.where_clauses = where_clauses;
 	return result;
 }
 
@@ -748,6 +761,18 @@ Ast *ast_range_stmt(AstFile *f, Token token, Ast *val0, Ast *val1, Token in_toke
 	return result;
 }
 
+Ast *ast_inline_range_stmt(AstFile *f, Token inline_token, Token for_token, Ast *val0, Ast *val1, Token in_token, Ast *expr, Ast *body) {
+	Ast *result = alloc_ast_node(f, Ast_InlineRangeStmt);
+	result->InlineRangeStmt.inline_token = inline_token;
+	result->InlineRangeStmt.for_token = for_token;
+	result->InlineRangeStmt.val0 = val0;
+	result->InlineRangeStmt.val1 = val1;
+	result->InlineRangeStmt.in_token = in_token;
+	result->InlineRangeStmt.expr  = expr;
+	result->InlineRangeStmt.body  = body;
+	return result;
+}
+
 Ast *ast_switch_stmt(AstFile *f, Token token, Ast *init, Ast *tag, Ast *body) {
 	Ast *result = alloc_ast_node(f, Ast_SwitchStmt);
 	result->SwitchStmt.token = token;
@@ -805,13 +830,14 @@ Ast *ast_bad_decl(AstFile *f, Token begin, Token end) {
 	return result;
 }
 
-Ast *ast_field(AstFile *f, Array<Ast *> names, Ast *type, Ast *default_value, u32 flags,
-                   CommentGroup *docs, CommentGroup *comment) {
+Ast *ast_field(AstFile *f, Array<Ast *> names, Ast *type, Ast *default_value, u32 flags, Token tag,
+               CommentGroup *docs, CommentGroup *comment) {
 	Ast *result = alloc_ast_node(f, Ast_Field);
 	result->Field.names         = names;
 	result->Field.type          = type;
 	result->Field.default_value = default_value;
 	result->Field.flags         = flags;
+	result->Field.tag           = tag;
 	result->Field.docs = docs;
 	result->Field.comment       = comment;
 	return result;
@@ -898,7 +924,8 @@ Ast *ast_dynamic_array_type(AstFile *f, Token token, Ast *elem) {
 
 Ast *ast_struct_type(AstFile *f, Token token, Array<Ast *> fields, isize field_count,
                      Ast *polymorphic_params, bool is_packed, bool is_raw_union,
-                     Ast *align) {
+                     Ast *align,
+                     Token where_token, Array<Ast *> const &where_clauses) {
 	Ast *result = alloc_ast_node(f, Ast_StructType);
 	result->StructType.token              = token;
 	result->StructType.fields             = fields;
@@ -907,17 +934,22 @@ Ast *ast_struct_type(AstFile *f, Token token, Array<Ast *> fields, isize field_c
 	result->StructType.is_packed          = is_packed;
 	result->StructType.is_raw_union       = is_raw_union;
 	result->StructType.align              = align;
+	result->StructType.where_token        = where_token;
+	result->StructType.where_clauses      = where_clauses;
 	return result;
 }
 
 
-Ast *ast_union_type(AstFile *f, Token token, Array<Ast *> variants, Ast *polymorphic_params, Ast *align, bool no_nil) {
+Ast *ast_union_type(AstFile *f, Token token, Array<Ast *> variants, Ast *polymorphic_params, Ast *align, bool no_nil,
+                    Token where_token, Array<Ast *> const &where_clauses) {
 	Ast *result = alloc_ast_node(f, Ast_UnionType);
 	result->UnionType.token              = token;
 	result->UnionType.variants           = variants;
 	result->UnionType.polymorphic_params = polymorphic_params;
 	result->UnionType.align              = align;
 	result->UnionType.no_nil             = no_nil;
+	result->UnionType.where_token        = where_token;
+	result->UnionType.where_clauses      = where_clauses;
 	return result;
 }
 
@@ -1118,6 +1150,17 @@ Token advance_token(AstFile *f) {
 	return prev;
 }
 
+bool peek_token_kind(AstFile *f, TokenKind kind) {
+	for (isize i = f->curr_token_index+1; i < f->tokens.count; i++) {
+		Token tok = f->tokens[i];
+		if (kind != Token_Comment && tok.kind == Token_Comment) {
+			continue;
+		}
+		return tok.kind == kind;
+	}
+	return false;
+}
+
 Token expect_token(AstFile *f, TokenKind kind) {
 	Token prev = f->curr_token;
 	if (prev.kind != kind) {
@@ -1302,7 +1345,8 @@ bool is_semicolon_optional_for_node(AstFile *f, Ast *s) {
 	case Ast_UnionType:
 	case Ast_EnumType:
 	case Ast_BitFieldType:
-		return true;
+		// Require semicolon within a procedure body
+		return f->curr_proc == nullptr;
 	case Ast_ProcLit:
 		return true;
 
@@ -1336,10 +1380,6 @@ void expect_semicolon(AstFile *f, Ast *s) {
 		return;
 	}
 
-	switch (f->curr_token.kind) {
-	case Token_EOF:
-		return;
-	}
 
 	if (s != nullptr) {
 		if (prev_token.pos.line != f->curr_token.pos.line) {
@@ -1352,12 +1392,21 @@ void expect_semicolon(AstFile *f, Ast *s) {
 			case Token_CloseParen:
 			case Token_else:
 				return;
+			case Token_EOF:
+				if (is_semicolon_optional_for_node(f, s)) {
+					return;
+				}
+				break;
 			}
 		}
 		String node_string = ast_strings[s->kind];
 		syntax_error(prev_token, "Expected ';' after %.*s, got %.*s",
-		             LIT(node_string), LIT(token_strings[prev_token.kind]));
+		             LIT(node_string), LIT(token_strings[f->curr_token.kind]));
 	} else {
+		switch (f->curr_token.kind) {
+		case Token_EOF:
+			return;
+		}
 		syntax_error(prev_token, "Expected ';'");
 	}
 	fix_advance_to_next_stmt(f);
@@ -1461,8 +1510,11 @@ Ast *parse_value(AstFile *f) {
 	if (f->curr_token.kind == Token_OpenBrace) {
 		return parse_literal_value(f, nullptr);
 	}
-
-	Ast *value = parse_expr(f, false);
+	Ast *value;
+	bool prev_allow_range = f->allow_range;
+	f->allow_range = true;
+	value = parse_expr(f, false);
+	f->allow_range = prev_allow_range;
 	return value;
 }
 
@@ -1614,7 +1666,7 @@ void check_polymorphic_params_for_type(AstFile *f, Ast *polymorphic_params, Toke
 		for_array(i, field->Field.names) {
 			Ast *name = field->Field.names[i];
 			if (name->kind == Ast_PolyType) {
-				error(name, "Polymorphic names are not needed for %.*s parameters", LIT(token.string));
+				syntax_error(name, "Polymorphic names are not needed for %.*s parameters", LIT(token.string));
 				return; // TODO(bill): Err multiple times or just the once?
 			}
 		}
@@ -1687,7 +1739,8 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 				operand = ast_bad_expr(f, token, f->curr_token);
 			}
 			operand->stmt_state_flags |= StmtStateFlag_no_deferred;
-		} */ else if (name.string == "file") { return ast_basic_directive(f, token, name.string);
+		} */ else if (name.string == "file") {
+			return ast_basic_directive(f, token, name.string);
 		} else if (name.string == "line") { return ast_basic_directive(f, token, name.string);
 		} else if (name.string == "procedure") { return ast_basic_directive(f, token, name.string);
 		} else if (name.string == "caller_location") { return ast_basic_directive(f, token, name.string);
@@ -1796,15 +1849,41 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 		}
 
 		Ast *type = parse_proc_type(f, token);
+		Token where_token = {};
+		Array<Ast *> where_clauses = {};
+		u64 tags = 0;
+
+		if (f->curr_token.kind == Token_where) {
+			where_token = expect_token(f, Token_where);
+			isize prev_level = f->expr_level;
+			f->expr_level = -1;
+			where_clauses = parse_rhs_expr_list(f);
+			f->expr_level = prev_level;
+		}
+
+		parse_proc_tags(f, &tags);
+		if ((tags & ProcTag_require_results) != 0) {
+			syntax_error(f->curr_token, "#require_results has now been replaced as an attribute @(require_results) on the declaration");
+			tags &= ~ProcTag_require_results;
+		}
+		GB_ASSERT(type->kind == Ast_ProcType);
+		type->ProcType.tags = tags;
 
 		if (f->allow_type && f->expr_level < 0) {
+			if (tags != 0) {
+				syntax_error(token, "A procedure type cannot have suffix tags");
+			}
+			if (where_token.kind != Token_Invalid) {
+				syntax_error(where_token, "'where' clauses are not allowed on procedure types");
+			}
 			return type;
 		}
 
-		u64 tags = type->ProcType.tags;
-
 		if (allow_token(f, Token_Undef)) {
-			return ast_proc_lit(f, type, nullptr, tags);
+			if (where_token.kind != Token_Invalid) {
+				syntax_error(where_token, "'where' clauses are not allowed on procedure literals without a defined body (replaced with ---)");
+			}
+			return ast_proc_lit(f, type, nullptr, tags, where_token, where_clauses);
 		} else if (f->curr_token.kind == Token_OpenBrace) {
 			Ast *curr_proc = f->curr_proc;
 			Ast *body = nullptr;
@@ -1812,7 +1891,7 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 			body = parse_body(f);
 			f->curr_proc = curr_proc;
 
-			return ast_proc_lit(f, type, body, tags);
+			return ast_proc_lit(f, type, body, tags, where_token, where_clauses);
 		} else if (allow_token(f, Token_do)) {
 			Ast *curr_proc = f->curr_proc;
 			Ast *body = nullptr;
@@ -1820,11 +1899,14 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 			body = convert_stmt_to_body(f, parse_stmt(f));
 			f->curr_proc = curr_proc;
 
-			return ast_proc_lit(f, type, body, tags);
+			return ast_proc_lit(f, type, body, tags, where_token, where_clauses);
 		}
 
 		if (tags != 0) {
-			syntax_error(token, "A procedure type cannot have tags");
+			syntax_error(token, "A procedure type cannot have suffix tags");
+		}
+		if (where_token.kind != Token_Invalid) {
+			syntax_error(where_token, "'where' clauses are not allowed on procedure types");
 		}
 
 		return type;
@@ -1847,10 +1929,6 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 
 	case Token_typeid: {
 		Token token = expect_token(f, Token_typeid);
-		// Ast *specialization = nullptr;
-		// if (allow_token(f, Token_Quo)) {
-		// 	specialization = parse_type(f);
-		// }
 		return ast_typeid_type(f, token, nullptr);
 	} break;
 
@@ -1952,6 +2030,18 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 			syntax_error(token, "'#raw_union' cannot also be '#packed'");
 		}
 
+		Token where_token = {};
+		Array<Ast *> where_clauses = {};
+
+		if (f->curr_token.kind == Token_where) {
+			where_token = expect_token(f, Token_where);
+			isize prev_level = f->expr_level;
+			f->expr_level = -1;
+			where_clauses = parse_rhs_expr_list(f);
+			f->expr_level = prev_level;
+		}
+
+
 		Token open = expect_token_after(f, Token_OpenBrace, "struct");
 
 		isize    name_count = 0;
@@ -1964,7 +2054,7 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 			decls = fields->FieldList.list;
 		}
 
-		return ast_struct_type(f, token, decls, name_count, polymorphic_params, is_packed, is_raw_union, align);
+		return ast_struct_type(f, token, decls, name_count, polymorphic_params, is_packed, is_raw_union, align, where_token, where_clauses);
 	} break;
 
 	case Token_union: {
@@ -2005,6 +2095,18 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 			}
 		}
 
+		Token where_token = {};
+		Array<Ast *> where_clauses = {};
+
+		if (f->curr_token.kind == Token_where) {
+			where_token = expect_token(f, Token_where);
+			isize prev_level = f->expr_level;
+			f->expr_level = -1;
+			where_clauses = parse_rhs_expr_list(f);
+			f->expr_level = prev_level;
+		}
+
+
 		Token open = expect_token_after(f, Token_OpenBrace, "union");
 
 		while (f->curr_token.kind != Token_CloseBrace &&
@@ -2020,7 +2122,7 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 
 		Token close = expect_token(f, Token_CloseBrace);
 
-		return ast_union_type(f, token, variants, polymorphic_params, align, no_nil);
+		return ast_union_type(f, token, variants, polymorphic_params, align, no_nil, where_token, where_clauses);
 	} break;
 
 	case Token_enum: {
@@ -2091,7 +2193,7 @@ Ast *parse_operand(AstFile *f, bool lhs) {
 
 		bool prev_allow_range = f->allow_range;
 		f->allow_range = true;
-		elem = parse_expr(f, false);
+		elem = parse_expr(f, true);
 		f->allow_range = prev_allow_range;
 		if (allow_token(f, Token_Semicolon)) {
 			underlying = parse_type(f);
@@ -2383,17 +2485,18 @@ i32 token_precedence(AstFile *f, TokenKind t) {
 	case Token_LtEq:
 	case Token_GtEq:
 		return 5;
+
 	case Token_in:
 	case Token_notin:
-		if (f->expr_level >= 0 || f->allow_in_expr) {
-			return 6;
+		if (f->expr_level < 0 && !f->allow_in_expr) {
+			return 0;
 		}
-		return 0;
+		/*fallthrough*/
 	case Token_Add:
 	case Token_Sub:
 	case Token_Or:
 	case Token_Xor:
-		return 7;
+		return 6;
 	case Token_Mul:
 	case Token_Quo:
 	case Token_Mod:
@@ -2402,7 +2505,7 @@ i32 token_precedence(AstFile *f, TokenKind t) {
 	case Token_AndNot:
 	case Token_Shl:
 	case Token_Shr:
-		return 8;
+		return 7;
 	}
 	return 0;
 }
@@ -2649,7 +2752,7 @@ Ast *parse_simple_stmt(AstFile *f, u32 flags) {
 			allow_token(f, Token_in);
 			bool prev_allow_range = f->allow_range;
 			f->allow_range = true;
-			Ast *expr = parse_expr(f, false);
+			Ast *expr = parse_expr(f, true);
 			f->allow_range = prev_allow_range;
 
 			auto rhs = array_make<Ast *>(heap_allocator(), 0, 1);
@@ -2740,7 +2843,8 @@ Ast *parse_results(AstFile *f, bool *diverging) {
 		Array<Ast *> empty_names = {};
 		auto list = array_make<Ast *>(heap_allocator(), 0, 1);
 		Ast *type = parse_type(f);
-		array_add(&list, ast_field(f, empty_names, type, nullptr, 0, nullptr, nullptr));
+		Token tag = {};
+		array_add(&list, ast_field(f, empty_names, type, nullptr, 0, tag, nullptr, nullptr));
 		return ast_field_list(f, begin_token, list);
 	}
 
@@ -2795,8 +2899,6 @@ Ast *parse_proc_type(AstFile *f, Token proc_token) {
 	results = parse_results(f, &diverging);
 
 	u64 tags = 0;
-	parse_proc_tags(f, &tags);
-
 	bool is_generic = false;
 
 	for_array(i, params->FieldList.list) {
@@ -3095,6 +3197,7 @@ Ast *parse_field_list(AstFile *f, isize *name_count_, u32 allowed_flags, TokenKi
 
 		Ast *type = nullptr;
 		Ast *default_value = nullptr;
+		Token tag = {};
 
 		expect_token_after(f, Token_Colon, "field list");
 		if (f->curr_token.kind != Token_Eq) {
@@ -3132,16 +3235,25 @@ Ast *parse_field_list(AstFile *f, isize *name_count_, u32 allowed_flags, TokenKi
 			syntax_error(f->curr_token, "Extra parameter after ellipsis without a default value");
 		}
 
+		if (type != nullptr && default_value == nullptr) {
+			if (f->curr_token.kind == Token_String) {
+				tag = expect_token(f, Token_String);
+				if ((allowed_flags & FieldFlag_Tags) == 0) {
+					syntax_error(tag, "Field tags are only allowed within structures");
+				}
+			}
+		}
+
 		parse_expect_field_separator(f, type);
-		Ast *param = ast_field(f, names, type, default_value, set_flags, docs, f->line_comment);
+		Ast *param = ast_field(f, names, type, default_value, set_flags, tag, docs, f->line_comment);
 		array_add(&params, param);
 
 
 		while (f->curr_token.kind != follow &&
 		       f->curr_token.kind != Token_EOF) {
 			CommentGroup *docs = f->lead_comment;
-
 			u32 set_flags = parse_field_prefixes(f);
+			Token tag = {};
 			Array<Ast *> names = parse_ident_list(f, allow_poly_names);
 			if (names.count == 0) {
 				syntax_error(f->curr_token, "Empty field declaration");
@@ -3184,9 +3296,18 @@ Ast *parse_field_list(AstFile *f, isize *name_count_, u32 allowed_flags, TokenKi
 				syntax_error(f->curr_token, "Extra parameter after ellipsis without a default value");
 			}
 
+			if (type != nullptr && default_value == nullptr) {
+				if (f->curr_token.kind == Token_String) {
+					tag = expect_token(f, Token_String);
+					if ((allowed_flags & FieldFlag_Tags) == 0) {
+						syntax_error(tag, "Field tags are only allowed within structures");
+					}
+				}
+			}
+
 
 			bool ok = parse_expect_field_separator(f, param);
-			Ast *param = ast_field(f, names, type, default_value, set_flags, docs, f->line_comment);
+			Ast *param = ast_field(f, names, type, default_value, set_flags, tag, docs, f->line_comment);
 			array_add(&params, param);
 
 			if (!ok) {
@@ -3210,8 +3331,8 @@ Ast *parse_field_list(AstFile *f, isize *name_count_, u32 allowed_flags, TokenKi
 		token.pos = ast_token(type).pos;
 		names[0] = ast_ident(f, token);
 		u32 flags = check_field_prefixes(f, list.count, allowed_flags, list[i].flags);
-
-		Ast *param = ast_field(f, names, list[i].node, nullptr, flags, docs, f->line_comment);
+		Token tag = {};
+		Ast *param = ast_field(f, names, list[i].node, nullptr, flags, tag, docs, f->line_comment);
 		array_add(&params, param);
 	}
 
@@ -3758,9 +3879,55 @@ Ast *parse_stmt(AstFile *f) {
 	Token token = f->curr_token;
 	switch (token.kind) {
 	// Operands
-	case Token_context: // Also allows for `context =`
 	case Token_inline:
+		if (peek_token_kind(f, Token_for)) {
+			Token inline_token = expect_token(f, Token_inline);
+			Token for_token = expect_token(f, Token_for);
+			Ast *val0 = nullptr;
+			Ast *val1 = nullptr;
+			Token in_token = {};
+			Ast *expr = nullptr;
+			Ast *body = nullptr;
+
+			bool bad_stmt = false;
+
+			if (f->curr_token.kind != Token_in) {
+				Array<Ast *> idents = parse_ident_list(f, false);
+				switch (idents.count) {
+				case 1:
+					val0 = idents[0];
+					break;
+				case 2:
+					val0 = idents[0];
+					val1 = idents[1];
+					break;
+				default:
+					syntax_error(for_token, "Expected either 1 or 2 identifiers");
+					bad_stmt = true;
+					break;
+				}
+			}
+			in_token = expect_token(f, Token_in);
+
+			bool prev_allow_range = f->allow_range;
+			f->allow_range = true;
+			expr = parse_expr(f, true);
+			f->allow_range = prev_allow_range;
+
+			if (allow_token(f, Token_do)) {
+				body = convert_stmt_to_body(f, parse_stmt(f));
+			} else {
+				body = parse_block_stmt(f, false);
+			}
+			if (bad_stmt) {
+				return ast_bad_stmt(f, inline_token, f->curr_token);
+			}
+			return ast_inline_range_stmt(f, inline_token, for_token, val0, val1, in_token, expr, body);
+		}
+		/* fallthrough */
 	case Token_no_inline:
+	case Token_context: // Also allows for `context =`
+	case Token_proc:
 	case Token_Ident:
 	case Token_Integer:
 	case Token_Float:
@@ -3808,34 +3975,6 @@ Ast *parse_stmt(AstFile *f) {
 		return s;
 	}
 
-	// case Token_static: {
-	// 	CommentGroup *docs = f->lead_comment;
-	// 	Token token = expect_token(f, Token_static);
-
-	// 	Ast *decl = nullptr;
-	// 	Array<Ast *> list = parse_lhs_expr_list(f);
-	// 	if (list.count == 0) {
-	// 		syntax_error(token, "Illegal use of 'static' statement");
-	// 		expect_semicolon(f, nullptr);
-	// 		return ast_bad_stmt(f, token, f->curr_token);
-	// 	}
-
-	// 	expect_token_after(f, Token_Colon, "identifier list");
-	// 	decl = parse_value_decl(f, list, docs);
-
-	// 	if (decl != nullptr && decl->kind == Ast_ValueDecl) {
-	// 		if (decl->ValueDecl.is_mutable) {
-	// 			decl->ValueDecl.is_static = true;
-	// 		} else {
-	// 			error(token, "'static' may only be currently used with variable declaration");
-	// 		}
-	// 		return decl;
-	// 	}
-
-	// 	syntax_error(token, "Illegal use of 'static' statement");
-	// 	return ast_bad_stmt(f, token, f->curr_token);
-	// } break;
-
 	case Token_using: {
 		CommentGroup *docs = f->lead_comment;
 		Token token = expect_token(f, Token_using);
@@ -3909,12 +4048,10 @@ Ast *parse_stmt(AstFile *f) {
 		} else if (tag == "assert") {
 			Ast *t = ast_basic_directive(f, hash_token, tag);
 			return ast_expr_stmt(f, parse_call_expr(f, t));
-		} /* else if (name.string == "no_deferred") {
-			s = parse_stmt(f);
-			s->stmt_state_flags |= StmtStateFlag_no_deferred;
-		} */
-
-		if (tag == "include") {
+		} else if (tag == "panic") {
+			Ast *t = ast_basic_directive(f, hash_token, tag);
+			return ast_expr_stmt(f, parse_call_expr(f, t));
+		} else if (tag == "include") {
 			syntax_error(token, "#include is not a valid import declaration kind. Did you mean 'import'?");
 			s = ast_bad_stmt(f, token, f->curr_token);
 		} else {
@@ -4037,7 +4174,6 @@ bool init_parser(Parser *p) {
 	map_init(&p->package_map, heap_allocator());
 	array_init(&p->packages, heap_allocator());
 	array_init(&p->package_imports, heap_allocator());
-	array_init(&p->files_to_process, heap_allocator());
 	gb_mutex_init(&p->file_add_mutex);
 	gb_mutex_init(&p->file_decl_mutex);
 	return true;
@@ -4060,7 +4196,6 @@ void destroy_parser(Parser *p) {
 #endif
 	array_free(&p->packages);
 	array_free(&p->package_imports);
-	array_free(&p->files_to_process);
 	string_set_destroy(&p->imported_files);
 	map_destroy(&p->package_map);
 	gb_mutex_destroy(&p->file_add_mutex);
@@ -4077,19 +4212,32 @@ void parser_add_package(Parser *p, AstPackage *pkg) {
 		if (found) {
 			GB_ASSERT(pkg->files.count > 0);
 			AstFile *f = pkg->files[0];
-			error(f->package_token, "Non-unique package name '%.*s'", LIT(pkg->name));
+			syntax_error(f->package_token, "Non-unique package name '%.*s'", LIT(pkg->name));
 			GB_ASSERT((*found)->files.count > 0);
 			TokenPos pos = (*found)->files[0]->package_token.pos;
-			gb_printf_err("\tpreviously declared at %.*s(%td:%td)", LIT(pos.file), pos.line, pos.column);
+			error_line("\tpreviously declared at %.*s(%td:%td)\n", LIT(pos.file), pos.line, pos.column);
 		} else {
 			map_set(&p->package_map, key, pkg);
 		}
 	}
 }
 
+ParseFileError process_imported_file(Parser *p, ImportedFile const &imported_file);
+
+WORKER_TASK_PROC(parser_worker_proc) {
+	ParserWorkerData *wd = cast(ParserWorkerData *)data;
+	ParseFileError err = process_imported_file(wd->parser, wd->imported_file);
+	return cast(isize)err;
+}
+
+
 void parser_add_file_to_process(Parser *p, AstPackage *pkg, FileInfo fi, TokenPos pos) {
-	ImportedFile f = {pkg, fi, pos, p->files_to_process.count};
-	array_add(&p->files_to_process, f);
+	// TODO(bill): Use a better allocator
+	ImportedFile f = {pkg, fi, pos, p->file_to_process_count++};
+	auto wd = gb_alloc_item(heap_allocator(), ParserWorkerData);
+	wd->parser = p;
+	wd->imported_file = f;
+	thread_pool_add_task(&parser_thread_pool, parser_worker_proc, wd);
 }
 
 
@@ -4140,22 +4288,22 @@ bool try_add_import_path(Parser *p, String const &path, String const &rel_path,
 
 	switch (rd_err) {
 	case ReadDirectory_InvalidPath:
-		error(pos, "Invalid path: %.*s", LIT(rel_path));
+		syntax_error(pos, "Invalid path: %.*s", LIT(rel_path));
 		return false;
 	case ReadDirectory_NotExists:
-		error(pos, "Path does not exist: %.*s", LIT(rel_path));
+		syntax_error(pos, "Path does not exist: %.*s", LIT(rel_path));
 		return false;
 	case ReadDirectory_Permission:
-		error(pos, "Unknown error whilst reading path %.*s", LIT(rel_path));
+		syntax_error(pos, "Unknown error whilst reading path %.*s", LIT(rel_path));
 		return false;
 	case ReadDirectory_NotDir:
-		error(pos, "Expected a directory for a package, got a file: %.*s", LIT(rel_path));
+		syntax_error(pos, "Expected a directory for a package, got a file: %.*s", LIT(rel_path));
 		return false;
 	case ReadDirectory_Empty:
-		error(pos, "Empty directory: %.*s", LIT(rel_path));
+		syntax_error(pos, "Empty directory: %.*s", LIT(rel_path));
 		return false;
 	case ReadDirectory_Unknown:
-		error(pos, "Unknown error whilst reading path %.*s", LIT(rel_path));
+		syntax_error(pos, "Unknown error whilst reading path %.*s", LIT(rel_path));
 		return false;
 	}
 
@@ -4257,7 +4405,7 @@ bool determine_path_from_string(gbMutex *file_mutex, Ast *node, String base_dir,
 
 	String file_str = {};
 	if (colon_pos == 0) {
-		error(node, "Expected a collection name");
+		syntax_error(node, "Expected a collection name");
 		return false;
 	}
 
@@ -4272,32 +4420,19 @@ bool determine_path_from_string(gbMutex *file_mutex, Ast *node, String base_dir,
 	if (has_windows_drive) {
 		String sub_file_path = substring(file_str, 3, file_str.len);
 		if (!is_import_path_valid(sub_file_path)) {
-			error(node, "Invalid import path: '%.*s'", LIT(file_str));
+			syntax_error(node, "Invalid import path: '%.*s'", LIT(file_str));
 			return false;
 		}
 	} else if (!is_import_path_valid(file_str)) {
-		error(node, "Invalid import path: '%.*s'", LIT(file_str));
+		syntax_error(node, "Invalid import path: '%.*s'", LIT(file_str));
 		return false;
 	}
 
 
-	if (is_package_name_reserved(file_str)) {
-		*path = file_str;
-		return true;
-	}
-
-	if (file_mutex) gb_mutex_lock(file_mutex);
-	defer (if (file_mutex) gb_mutex_unlock(file_mutex));
-
-
-	if (node->kind == Ast_ForeignImportDecl) {
-		node->ForeignImportDecl.collection_name = collection_name;
-	}
-
 	if (collection_name.len > 0) {
 		if (collection_name == "system") {
 			if (node->kind != Ast_ForeignImportDecl) {
-				error(node, "The library collection 'system' is restrict for 'foreign_library'");
+				syntax_error(node, "The library collection 'system' is restrict for 'foreign_library'");
 				return false;
 			} else {
 				*path = file_str;
@@ -4305,7 +4440,7 @@ bool determine_path_from_string(gbMutex *file_mutex, Ast *node, String base_dir,
 			}
 		} else if (!find_library_collection_path(collection_name, &base_dir)) {
 			// NOTE(bill): It's a naughty name
-			error(node, "Unknown library collection: '%.*s'", LIT(collection_name));
+			syntax_error(node, "Unknown library collection: '%.*s'", LIT(collection_name));
 			return false;
 		}
 	} else {
@@ -4324,6 +4459,20 @@ bool determine_path_from_string(gbMutex *file_mutex, Ast *node, String base_dir,
 #endif
 	}
 
+
+	if (is_package_name_reserved(file_str)) {
+		*path = file_str;
+		return true;
+	}
+
+	if (file_mutex) gb_mutex_lock(file_mutex);
+	defer (if (file_mutex) gb_mutex_unlock(file_mutex));
+
+
+	if (node->kind == Ast_ForeignImportDecl) {
+		node->ForeignImportDecl.collection_name = collection_name;
+	}
+
 	if (has_windows_drive) {
 		*path = file_str;
 	} else {
@@ -4412,7 +4561,7 @@ void parse_setup_file_decls(Parser *p, AstFile *f, String base_dir, Array<Ast *>
 				array_add(&fl->fullpaths, fullpath);
 			}
 			if (fl->fullpaths.count == 0) {
-				error(decls[i], "No foreign paths found");
+				syntax_error(decls[i], "No foreign paths found");
 				decls[i] = ast_bad_decl(f, fl->filepaths[0], fl->filepaths[fl->filepaths.count-1]);
 				goto end;
 			}
@@ -4461,7 +4610,7 @@ bool parse_build_tag(Token token_for_pos, String s) {
 			is_notted = true;
 			p = substring(p, 1, p.len);
 			if (p.len == 0) {
-				error(token_for_pos, "Expected a build platform after '!'");
+				syntax_error(token_for_pos, "Expected a build platform after '!'");
 				break;
 			}
 		}
@@ -4490,7 +4639,7 @@ bool parse_build_tag(Token token_for_pos, String s) {
 				}
 			}
 			if (os == TargetOs_Invalid && arch == TargetArch_Invalid) {
-				error(token_for_pos, "Invalid build tag platform: %.*s", LIT(p));
+				syntax_error(token_for_pos, "Invalid build tag platform: %.*s", LIT(p));
 				break;
 			}
 		}
@@ -4536,11 +4685,11 @@ bool parse_file(Parser *p, AstFile *f) {
 	Token package_name = expect_token_after(f, Token_Ident, "package");
 	if (package_name.kind == Token_Ident) {
 		if (package_name.string == "_") {
-			error(package_name, "Invalid package name '_'");
+			syntax_error(package_name, "Invalid package name '_'");
 		} else if (f->pkg->kind != Package_Runtime && package_name.string == "runtime") {
-			error(package_name, "Use of reserved package name '%.*s'", LIT(package_name.string));
+			syntax_error(package_name, "Use of reserved package name '%.*s'", LIT(package_name.string));
 		} else if (is_package_name_reserved(package_name.string)) {
-			error(package_name, "Use of reserved package name '%.*s'", LIT(package_name.string));
+			syntax_error(package_name, "Use of reserved package name '%.*s'", LIT(package_name.string));
 		}
 	}
 	f->package_name = package_name.string;
@@ -4590,9 +4739,9 @@ bool parse_file(Parser *p, AstFile *f) {
 }
 
 
-ParseFileError process_imported_file(Parser *p, ImportedFile imported_file) {
+ParseFileError process_imported_file(Parser *p, ImportedFile const &imported_file) {
 	AstPackage *pkg = imported_file.pkg;
-	FileInfo *fi = &imported_file.fi;
+	FileInfo const *fi = &imported_file.fi;
 	TokenPos pos = imported_file.pos;
 
 	AstFile *file = gb_alloc_item(heap_allocator(), AstFile);
@@ -4607,38 +4756,35 @@ ParseFileError process_imported_file(Parser *p, ImportedFile imported_file) {
 	if (err != ParseFile_None) {
 		if (err == ParseFile_EmptyFile) {
 			if (fi->fullpath == p->init_fullpath) {
-				error(pos, "Initial file is empty - %.*s\n", LIT(p->init_fullpath));
+				syntax_error(pos, "Initial file is empty - %.*s\n", LIT(p->init_fullpath));
 				gb_exit(1);
 			}
-			goto skip;
-		}
+		} else {
+			switch (err) {
+			case ParseFile_WrongExtension:
+				syntax_error(pos, "Failed to parse file: %.*s; invalid file extension: File must have the extension '.odin'", LIT(fi->name));
+				break;
+			case ParseFile_InvalidFile:
+				syntax_error(pos, "Failed to parse file: %.*s; invalid file or cannot be found", LIT(fi->name));
+				break;
+			case ParseFile_Permission:
+				syntax_error(pos, "Failed to parse file: %.*s; file permissions problem", LIT(fi->name));
+				break;
+			case ParseFile_NotFound:
+				syntax_error(pos, "Failed to parse file: %.*s; file cannot be found ('%.*s')", LIT(fi->name), LIT(fi->fullpath));
+				break;
+			case ParseFile_InvalidToken:
+				syntax_error(err_pos, "Failed to parse file: %.*s; invalid token found in file", LIT(fi->name));
+				break;
+			case ParseFile_EmptyFile:
+				syntax_error(pos, "Failed to parse file: %.*s; file contains no tokens", LIT(fi->name));
+				break;
+			}
 
-		switch (err) {
-		case ParseFile_WrongExtension:
-			error(pos, "Failed to parse file: %.*s; invalid file extension: File must have the extension '.odin'", LIT(fi->name));
-			break;
-		case ParseFile_InvalidFile:
-			error(pos, "Failed to parse file: %.*s; invalid file or cannot be found", LIT(fi->name));
-			break;
-		case ParseFile_Permission:
-			error(pos, "Failed to parse file: %.*s; file permissions problem", LIT(fi->name));
-			break;
-		case ParseFile_NotFound:
-			error(pos, "Failed to parse file: %.*s; file cannot be found ('%.*s')", LIT(fi->name), LIT(fi->fullpath));
-			break;
-		case ParseFile_InvalidToken:
-			error(err_pos, "Failed to parse file: %.*s; invalid token found in file", LIT(fi->name));
-			break;
-		case ParseFile_EmptyFile:
-			error(pos, "Failed to parse file: %.*s; file contains no tokens", LIT(fi->name));
-			break;
+			return err;
 		}
-
-		return err;
 	}
 
-
-skip:
 	if (parse_file(p, file)) {
 		gb_mutex_lock(&p->file_add_mutex);
 		defer (gb_mutex_unlock(&p->file_add_mutex));
@@ -4648,42 +4794,33 @@ skip:
 		if (pkg->name.len == 0) {
 			pkg->name = file->package_name;
 		} else if (file->tokens.count > 0 && pkg->name != file->package_name) {
-			error(file->package_token, "Different package name, expected '%.*s', got '%.*s'", LIT(pkg->name), LIT(file->package_name));
+			syntax_error(file->package_token, "Different package name, expected '%.*s', got '%.*s'", LIT(pkg->name), LIT(file->package_name));
 		}
 
 		p->total_line_count += file->tokenizer.line_count;
 		p->total_token_count += file->tokens.count;
 	}
+
 	return ParseFile_None;
 }
 
 
-GB_THREAD_PROC(parse_worker_file_proc) {
-	if (thread == nullptr) return 0;
-	auto *p = cast(Parser *)thread->user_data;
-	isize index = thread->user_index;
-	gb_mutex_lock(&p->file_add_mutex);
-	auto file_to_process = p->files_to_process[index];
-	gb_mutex_unlock(&p->file_add_mutex);
-	ParseFileError err = process_imported_file(p, file_to_process);
-	return cast(isize)err;
-}
-
 ParseFileError parse_packages(Parser *p, String init_filename) {
 	GB_ASSERT(init_filename.text[init_filename.len] == 0);
 
-	// char *fullpath_str = gb_path_get_full_name(heap_allocator(), cast(char const *)&init_filename[0]);
-	// String init_fullpath = string_trim_whitespace(make_string_c(fullpath_str));
+	isize thread_count = gb_max(build_context.thread_count, 1);
+	isize worker_count = thread_count-1; // NOTE(bill): The main thread will also be used for work
+	thread_pool_init(&parser_thread_pool, heap_allocator(), worker_count, "ParserWork");
+
 	String init_fullpath = path_to_full_path(heap_allocator(), init_filename);
 	if (!path_is_directory(init_fullpath)) {
 		String const ext = str_lit(".odin");
 		if (!string_ends_with(init_fullpath, ext)) {
-			gb_printf_err("Expected either a directory or a .odin file, got '%.*s'\n", LIT(init_filename));
+			error_line("Expected either a directory or a .odin file, got '%.*s'\n", LIT(init_filename));
 			return ParseFile_WrongExtension;
 		}
 	}
 
-
 	TokenPos init_pos = {};
 	if (!build_context.generate_docs) {
 		String s = get_fullpath_core(heap_allocator(), str_lit("runtime"));
@@ -4693,76 +4830,17 @@ ParseFileError parse_packages(Parser *p, String init_filename) {
 	try_add_import_path(p, init_fullpath, init_fullpath, init_pos, Package_Init);
 	p->init_fullpath = init_fullpath;
 
-#if 1
-	isize thread_count = gb_max(build_context.thread_count, 1);
-	if (thread_count > 1) {
-		isize volatile curr_import_index = 0;
-		isize initial_file_count = p->files_to_process.count;
-		// NOTE(bill): Make sure that these are in parsed in this order
-		for (isize i = 0; i < initial_file_count; i++) {
-			ParseFileError err = process_imported_file(p, p->files_to_process[i]);
-			if (err != ParseFile_None) {
-				return err;
-			}
-			curr_import_index++;
-		}
-
-		auto worker_threads = array_make<gbThread>(heap_allocator(), thread_count);
-		defer (array_free(&worker_threads));
-
-		for_array(i, worker_threads) {
-			gbThread *t = &worker_threads[i];
-			gb_thread_init(t);
-		}
-		defer (for_array(i, worker_threads) {
-			gb_thread_destroy(&worker_threads[i]);
-		});
+	thread_pool_start(&parser_thread_pool);
+	thread_pool_wait_to_process(&parser_thread_pool);
 
-		auto errors = array_make<ParseFileError>(heap_allocator(), 0, 16);
-
-		for (;;) {
-			bool are_any_alive = false;
-			for_array(i, worker_threads) {
-				gbThread *t = &worker_threads[i];
-				if (gb_thread_is_running(t)) {
-					are_any_alive = true;
-				} else if (curr_import_index < p->files_to_process.count) {
-					auto curr_err = cast(ParseFileError)t->return_value;
-					if (curr_err != ParseFile_None) {
-						array_add(&errors, curr_err);
-					} else {
-						t->user_index = curr_import_index;
-						curr_import_index++;
-						gb_thread_start(t, parse_worker_file_proc, p);
-						are_any_alive = true;
-					}
-				}
-			}
-			if (!are_any_alive && curr_import_index >= p->files_to_process.count) {
-				break;
-			}
-		}
-
-		if (errors.count > 0) {
-			return errors[errors.count-1];
-		}
-	} else {
-		for_array(i, p->files_to_process) {
-			ParseFileError err = process_imported_file(p, p->files_to_process[i]);
-			if (err != ParseFile_None) {
-				return err;
-			}
-		}
-	}
-#else
-	for_array(i, p->files_to_process) {
-		ImportedFile f = p->files_to_process[i];
-		ParseFileError err = process_imported_file(p, f);
+	// NOTE(bill): Get the last error and use that
+	for (isize i = parser_thread_pool.task_tail-1; i >= 0; i--) {
+		WorkerTask *task = &parser_thread_pool.tasks[i];
+		ParseFileError err = cast(ParseFileError)task->result;
 		if (err != ParseFile_None) {
 			return err;
 		}
 	}
-#endif
 
 	return ParseFile_None;
 }
diff --git a/src/parser.hpp b/src/parser.hpp
index 9f4f68a7b..f07f3ce0d 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -134,13 +134,26 @@ struct Parser {
 	Map<AstPackage *>      package_map; // Key: String (package name)
 	Array<AstPackage *>    packages;
 	Array<ImportedPackage> package_imports;
-	Array<ImportedFile>    files_to_process;
+	isize                  file_to_process_count;
 	isize                  total_token_count;
 	isize                  total_line_count;
 	gbMutex                file_add_mutex;
 	gbMutex                file_decl_mutex;
 };
 
+
+gb_global ThreadPool parser_thread_pool = {};
+
+struct ParserWorkerData {
+	Parser *parser;
+	ImportedFile imported_file;
+};
+
+
+
+
+
+
 enum ProcInlining {
 	ProcInlining_none = 0,
 	ProcInlining_inline = 1,
@@ -186,11 +199,12 @@ enum FieldFlag {
 	FieldFlag_c_vararg  = 1<<3,
 	FieldFlag_auto_cast = 1<<4,
 
+	FieldFlag_Tags = 1<<10,
 
 	FieldFlag_Results   = 1<<16,
 
 	FieldFlag_Signature = FieldFlag_ellipsis|FieldFlag_using|FieldFlag_no_alias|FieldFlag_c_vararg|FieldFlag_auto_cast,
-	FieldFlag_Struct    = FieldFlag_using,
+	FieldFlag_Struct    = FieldFlag_using|FieldFlag_Tags,
 };
 
 enum StmtAllowFlag {
@@ -208,6 +222,7 @@ enum StmtAllowFlag {
 	AST_KIND(Undef,          "undef",           Token) \
 	AST_KIND(BasicLit,       "basic literal",   struct { \
 		Token token; \
+		ExactValue value; \
 	}) \
 	AST_KIND(BasicDirective, "basic directive", struct { \
 		Token  token; \
@@ -228,11 +243,14 @@ enum StmtAllowFlag {
 		Ast *body; \
 		u64  tags; \
 		ProcInlining inlining; \
+		Token where_token; \
+		Array<Ast *> where_clauses; \
 	}) \
 	AST_KIND(CompoundLit, "compound literal", struct { \
 		Ast *type; \
 		Array<Ast *> elems; \
 		Token open, close; \
+		i64 max_count; \
 	}) \
 AST_KIND(_ExprBegin,  "",  bool) \
 	AST_KIND(BadExpr,      "bad expression",         struct { Token begin, end; }) \
@@ -325,6 +343,15 @@ AST_KIND(_ComplexStmtBegin, "", bool) \
 		Ast *expr; \
 		Ast *body; \
 	}) \
+	AST_KIND(InlineRangeStmt, "inline range statement", struct { \
+		Token inline_token; \
+		Token for_token; \
+		Ast *val0; \
+		Ast *val1; \
+		Token in_token; \
+		Ast *expr; \
+		Ast *body; \
+	}) \
 	AST_KIND(CaseClause, "case clause", struct { \
 		Token token;             \
 		Array<Ast *> list;   \
@@ -412,6 +439,7 @@ AST_KIND(_DeclEnd,   "", bool) \
 		Array<Ast *> names;         \
 		Ast *        type;          \
 		Ast *        default_value; \
+		Token        tag;           \
 		u32              flags;     \
 		CommentGroup *   docs;      \
 		CommentGroup *   comment;   \
@@ -465,20 +493,24 @@ AST_KIND(_TypeBegin, "", bool) \
 		Ast *elem; \
 	}) \
 	AST_KIND(StructType, "struct type", struct { \
-		Token token;              \
-		Array<Ast *> fields;      \
-		isize field_count;        \
-		Ast *polymorphic_params;  \
-		Ast *align;               \
-		bool is_packed;           \
-		bool is_raw_union;        \
+		Token token;                \
+		Array<Ast *> fields;        \
+		isize field_count;          \
+		Ast *polymorphic_params;    \
+		Ast *align;                 \
+		Token where_token;          \
+		Array<Ast *> where_clauses; \
+		bool is_packed;             \
+		bool is_raw_union;          \
 	}) \
 	AST_KIND(UnionType, "union type", struct { \
-		Token        token;      \
-		Array<Ast *> variants;   \
-		Ast *polymorphic_params; \
-		Ast *        align;      \
-		bool         no_nil;     \
+		Token        token;         \
+		Array<Ast *> variants;      \
+		Ast *polymorphic_params;    \
+		Ast *        align;         \
+		bool         no_nil;        \
+		Token where_token;          \
+		Array<Ast *> where_clauses; \
 	}) \
 	AST_KIND(EnumType, "enum type", struct { \
 		Token        token; \
diff --git a/src/priority_queue.cpp b/src/priority_queue.cpp
index 7c36e6a22..aee2061b5 100644
--- a/src/priority_queue.cpp
+++ b/src/priority_queue.cpp
@@ -20,7 +20,7 @@ bool priority_queue_shift_down(PriorityQueue<T> *pq, isize i0, isize n) {
 		if (j2 < n && pq->cmp(&pq->queue[0], j2, j1) < 0) {
 			j = j2;
 		}
-		if (pq->cmp(&pq->queue[0], i, j) < 0) break;
+		if (pq->cmp(&pq->queue[0], j, i) >= 0) break;
 
 		pq->swap(&pq->queue[0], i, j);
 		i = j;
@@ -32,7 +32,7 @@ template <typename T>
 void priority_queue_shift_up(PriorityQueue<T> *pq, isize j) {
 	while (0 <= j && j < pq->queue.count) {
 		isize i = (j-1)/2;
-		if (i == j || pq->cmp(&pq->queue[0], i, j) < 0) {
+		if (i == j || pq->cmp(&pq->queue[0], j, i) >= 0) {
 			break;
 		}
 		pq->swap(&pq->queue[0], i, j);
diff --git a/src/range_cache.cpp b/src/range_cache.cpp
new file mode 100644
index 000000000..9701fb432
--- /dev/null
+++ b/src/range_cache.cpp
@@ -0,0 +1,70 @@
+
+// Integers only
+struct RangeValue {
+	i64 lo;
+	i64 hi;
+};
+
+struct RangeCache {
+	Array<RangeValue> ranges;
+};
+
+
+RangeCache range_cache_make(gbAllocator a) {
+	RangeCache cache = {};
+	array_init(&cache.ranges, a);
+	return cache;
+}
+
+void range_cache_destroy(RangeCache *c) {
+	array_free(&c->ranges);
+}
+
+bool range_cache_add_index(RangeCache *c, i64 index) {
+	for_array(i, c->ranges) {
+		RangeValue v = c->ranges[i];
+		if (v.lo <= index && index <= v.hi) {
+			return false;
+		}
+	}
+	RangeValue v = {index, index};
+	array_add(&c->ranges, v);
+	return true;
+}
+
+
+bool range_cache_add_range(RangeCache *c, i64 lo, i64 hi) {
+	GB_ASSERT(lo <= hi);
+	for_array(i, c->ranges) {
+		RangeValue v = c->ranges[i];
+		if (hi < v.lo) {
+			continue;
+		}
+		if (lo > v.hi) {
+			continue;
+		}
+
+		if (v.hi < hi) {
+			v.hi = hi;
+		}
+		if (lo < v.lo) {
+			v.lo = lo;
+		}
+		c->ranges[i] = v;
+		return false;
+	}
+	RangeValue v = {lo, hi};
+	array_add(&c->ranges, v);
+	return true;
+}
+
+
+bool range_cache_index_exists(RangeCache *c, i64 index) {
+	for_array(i, c->ranges) {
+		RangeValue v = c->ranges[i];
+		if (v.lo <= index && index <= v.hi) {
+			return true;
+		}
+	}
+	return false;
+}
diff --git a/src/string.cpp b/src/string.cpp
index 774061edf..6812c5c39 100644
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -404,7 +404,7 @@ String16 string_to_string16(gbAllocator a, String s) {
 	}
 	text[len] = 0;
 
-	return make_string16(text, len-1);
+	return make_string16(text, len);
 }
 
 
@@ -440,12 +440,94 @@ String string16_to_string(gbAllocator a, String16 s) {
 
 
 
+bool is_printable(Rune r) {
+	if (r <= 0xff) {
+		if (0x20 <= r && r <= 0x7e) {
+			return true;
+		}
+		if (0xa1 <= r && r <= 0xff) {
+			return r != 0xad;
+		}
+		return false;
+	}
+	return false;
+}
 
+gb_global char const lower_hex[] = "0123456789abcdef";
+
+String quote_to_ascii(gbAllocator a, String str, u8 quote='"') {
+	u8 *s = str.text;
+	isize n = str.len;
+	auto buf = array_make<u8>(a, 0, n);
+	array_add(&buf, quote);
+	for (isize width = 0; n > 0; s += width, n -= width) {
+		Rune r = cast(Rune)s[0];
+		width = 1;
+		if (r >= 0x80) {
+			width = gb_utf8_decode(s, n, &r);
+		}
+		if (width == 1 && r == GB_RUNE_INVALID) {
+			array_add(&buf, cast(u8)'\\');
+			array_add(&buf, cast(u8)'x');
+			array_add(&buf, cast(u8)lower_hex[s[0]>>4]);
+			array_add(&buf, cast(u8)lower_hex[s[0]&0xf]);
+			continue;
+		}
 
+		if (r == quote || r == '\\') {
+			array_add(&buf, cast(u8)'\\');
+			array_add(&buf, u8(r));
+			continue;
+		}
+		if (r < 0x80 && is_printable(r)) {
+			array_add(&buf, u8(r));
+			continue;
+		}
+		switch (r) {
+		case '\a':
+		case '\b':
+		case '\f':
+		case '\n':
+		case '\r':
+		case '\t':
+		case '\v':
+		default:
+			if (r < ' ') {
+				u8 b = cast(u8)r;
+				array_add(&buf, cast(u8)'\\');
+				array_add(&buf, cast(u8)'x');
+				array_add(&buf, cast(u8)lower_hex[b>>4]);
+				array_add(&buf, cast(u8)lower_hex[b&0xf]);
+			}
+			if (r > GB_RUNE_MAX) {
+				r = 0XFFFD;
+			}
+			if (r < 0x10000) {
+				u8 b = cast(u8)r;
+				array_add(&buf, cast(u8)'\\');
+				array_add(&buf, cast(u8)'u');
+				for (isize i = 12; i >= 0; i -= 4) {
+					array_add(&buf, cast(u8)lower_hex[(r>>i)&0xf]);
+				}
+			} else {
+				u8 b = cast(u8)r;
+				array_add(&buf, cast(u8)'\\');
+				array_add(&buf, cast(u8)'U');
+				for (isize i = 28; i >= 0; i -= 4) {
+					array_add(&buf, cast(u8)lower_hex[(r>>i)&0xf]);
+				}
+			}
+		}
+	}
 
 
 
-
+	array_add(&buf, quote);
+	String res = {};
+	res.text = buf.data;
+	res.len = buf.count;
+	return res;
+}
 
 
 
diff --git a/src/thread_pool.cpp b/src/thread_pool.cpp
new file mode 100644
index 000000000..2467ba609
--- /dev/null
+++ b/src/thread_pool.cpp
@@ -0,0 +1,184 @@
+// worker_queue.cpp
+
+#define WORKER_TASK_PROC(name) isize name(void *data)
+typedef WORKER_TASK_PROC(WorkerTaskProc);
+
+struct WorkerTask {
+	WorkerTaskProc *do_work;
+	void *data;
+	isize result;
+};
+
+
+struct ThreadPool {
+	gbMutex     mutex;
+	gbSemaphore sem_available;
+	gbAtomic32  processing_work_count;
+	bool        is_running;
+
+	gbAllocator allocator;
+
+	WorkerTask *tasks;
+	isize volatile task_head;
+	isize volatile task_tail;
+	isize volatile task_capacity;
+
+	gbThread *threads;
+	isize thread_count;
+
+	char worker_prefix[10];
+	i32 worker_prefix_len;
+};
+
+void thread_pool_init(ThreadPool *pool, gbAllocator const &a, isize thread_count, char const *worker_prefix = nullptr);
+void thread_pool_destroy(ThreadPool *pool);
+void thread_pool_start(ThreadPool *pool);
+void thread_pool_join(ThreadPool *pool);
+void thread_pool_add_task(ThreadPool *pool, WorkerTaskProc *proc, void *data);
+void thread_pool_kick(ThreadPool *pool);
+void thread_pool_kick_and_wait(ThreadPool *pool);
+GB_THREAD_PROC(worker_thread_internal);
+
+void thread_pool_init(ThreadPool *pool, gbAllocator const &a, isize thread_count, char const *worker_prefix) {
+	pool->allocator = a;
+	pool->task_head = 0;
+	pool->task_tail = 0;
+	pool->task_capacity = 1024;
+	pool->tasks = gb_alloc_array(a, WorkerTask, pool->task_capacity);
+	pool->thread_count = gb_max(thread_count, 0);
+	pool->threads = gb_alloc_array(a, gbThread, pool->thread_count);
+	gb_mutex_init(&pool->mutex);
+	gb_semaphore_init(&pool->sem_available);
+	pool->is_running = true;
+
+	pool->worker_prefix_len = 0;
+	if (worker_prefix) {
+		i32 worker_prefix_len = cast(i32)gb_strlen(worker_prefix);
+		worker_prefix_len = gb_min(worker_prefix_len, 10);
+		gb_memmove(pool->worker_prefix, worker_prefix, worker_prefix_len);
+		pool->worker_prefix_len = worker_prefix_len;
+	}
+
+	for (isize i = 0; i < pool->thread_count; i++) {
+		gbThread *t = &pool->threads[i];
+		gb_thread_init(t);
+		t->user_index = i;
+		#if 0
+		// TODO(bill): Fix this on Linux as it causes a seg-fault
+		if (pool->worker_prefix_len > 0) {
+			char worker_name[16] = {};
+			gb_snprintf(worker_name, gb_size_of(worker_name), "%.*s%u", pool->worker_prefix_len, pool->worker_prefix, cast(u16)i);
+			gb_thread_set_name(t, worker_name);
+		}
+		#endif
+	}
+}
+
+void thread_pool_start(ThreadPool *pool) {
+	for (isize i = 0; i < pool->thread_count; i++) {
+		gbThread *t = &pool->threads[i];
+		gb_thread_start(t, worker_thread_internal, pool);
+	}
+}
+
+void thread_pool_join(ThreadPool *pool) {
+	pool->is_running = false;
+
+	gb_semaphore_post(&pool->sem_available, cast(i32)pool->thread_count);
+
+	gb_yield();
+
+	for (isize i = 0; i < pool->thread_count; i++) {
+		gbThread *t = &pool->threads[i];
+		gb_thread_join(t);
+	}
+}
+
+
+void thread_pool_destroy(ThreadPool *pool) {
+	thread_pool_join(pool);
+
+	gb_semaphore_destroy(&pool->sem_available);
+	gb_mutex_destroy(&pool->mutex);
+	gb_free(pool->allocator, pool->threads);
+	pool->thread_count = 0;
+	gb_free(pool->allocator, pool->tasks);
+	pool->task_head = 0;
+	pool->task_tail = 0;
+	pool->task_capacity = 0;
+}
+
+
+void thread_pool_add_task(ThreadPool *pool, WorkerTaskProc *proc, void *data) {
+	gb_mutex_lock(&pool->mutex);
+
+	if (pool->task_tail == pool->task_capacity) {
+		isize new_cap = 2*pool->task_capacity + 8;
+		WorkerTask *new_tasks = gb_alloc_array(pool->allocator, WorkerTask, new_cap);
+		gb_memmove(new_tasks, pool->tasks, (pool->task_tail)*gb_size_of(WorkerTask));
+		pool->tasks = new_tasks;
+		pool->task_capacity = new_cap;
+	}
+	WorkerTask task = {};
+	task.do_work = proc;
+	task.data = data;
+
+	pool->tasks[pool->task_tail++] = task;
+	gb_semaphore_post(&pool->sem_available, 1);
+	gb_mutex_unlock(&pool->mutex);
+}
+
+bool thread_pool_try_and_pop_task(ThreadPool *pool, WorkerTask *task) {
+	bool got_task = false;
+	if (gb_mutex_try_lock(&pool->mutex)) {
+		if (pool->task_tail > pool->task_head) {
+			gb_atomic32_fetch_add(&pool->processing_work_count, +1);
+			*task = pool->tasks[pool->task_head++];
+			got_task = true;
+		}
+		gb_mutex_unlock(&pool->mutex);
+	}
+	return got_task;
+}
+void thread_pool_do_work(ThreadPool *pool, WorkerTask *task) {
+	task->result = task->do_work(task->data);
+	gb_atomic32_fetch_add(&pool->processing_work_count, -1);
+}
+
+void thread_pool_wait_to_process(ThreadPool *pool) {
+	while (pool->task_tail > pool->task_head || gb_atomic32_load(&pool->processing_work_count) != 0) {
+		WorkerTask task = {};
+		if (thread_pool_try_and_pop_task(pool, &task)) {
+			thread_pool_do_work(pool, &task);
+		}
+
+		// Safety-kick
+		if (pool->task_tail > pool->task_head && gb_atomic32_load(&pool->processing_work_count) == 0) {
+			gb_mutex_lock(&pool->mutex);
+			gb_semaphore_post(&pool->sem_available, cast(i32)(pool->task_tail-pool->task_head));
+			gb_mutex_unlock(&pool->mutex);
+		}
+
+		gb_yield();
+	}
+
+	thread_pool_join(pool);
+}
+
+
+GB_THREAD_PROC(worker_thread_internal) {
+	ThreadPool *pool = cast(ThreadPool *)thread->user_data;
+	while (pool->is_running) {
+		gb_semaphore_wait(&pool->sem_available);
+
+		WorkerTask task = {};
+		if (thread_pool_try_and_pop_task(pool, &task)) {
+			thread_pool_do_work(pool, &task);
+		}
+	}
+	// Cascade
+	gb_semaphore_release(&pool->sem_available);
+
+	return 0;
+}
+
diff --git a/src/tokenizer.cpp b/src/tokenizer.cpp
index a551f0545..4b0db7ac4 100644
--- a/src/tokenizer.cpp
+++ b/src/tokenizer.cpp
@@ -86,6 +86,7 @@ TOKEN_KIND(Token__KeywordBegin, ""), \
 	TOKEN_KIND(Token_package,     "package"),     \
 	TOKEN_KIND(Token_typeid,      "typeid"),      \
 	TOKEN_KIND(Token_when,        "when"),        \
+	TOKEN_KIND(Token_where,       "where"),       \
 	TOKEN_KIND(Token_if,          "if"),          \
 	TOKEN_KIND(Token_else,        "else"),        \
 	TOKEN_KIND(Token_for,         "for"),         \
@@ -400,6 +401,15 @@ void syntax_error(Token token, char *fmt, ...) {
 	va_end(va);
 }
 
+void syntax_error(TokenPos pos, char *fmt, ...) {
+	va_list va;
+	va_start(va, fmt);
+	Token token = {};
+	token.pos = pos;
+	syntax_error_va(token, fmt, va);
+	va_end(va);
+}
+
 void syntax_warning(Token token, char *fmt, ...) {
 	va_list va;
 	va_start(va, fmt);
@@ -745,9 +755,11 @@ exponent:
 		scan_mantissa(t, 10);
 	}
 
-	if (t->curr_rune == 'i') {
+	switch (t->curr_rune) {
+	case 'i': case 'j': case 'k':
 		token.kind = Token_Imag;
 		advance_to_next_rune(t);
+		break;
 	}
 
 end:
diff --git a/src/types.cpp b/src/types.cpp
index dc7ecb946..bef69ee30 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -32,6 +32,9 @@ enum BasicKind {
 	Basic_complex64,
 	Basic_complex128,
 
+	Basic_quaternion128,
+	Basic_quaternion256,
+
 	Basic_int,
 	Basic_uint,
 	Basic_uintptr,
@@ -66,6 +69,7 @@ enum BasicKind {
 	Basic_UntypedInteger,
 	Basic_UntypedFloat,
 	Basic_UntypedComplex,
+	Basic_UntypedQuaternion,
 	Basic_UntypedString,
 	Basic_UntypedRune,
 	Basic_UntypedNil,
@@ -82,17 +86,18 @@ enum BasicFlag {
 	BasicFlag_Unsigned    = GB_BIT(2),
 	BasicFlag_Float       = GB_BIT(3),
 	BasicFlag_Complex     = GB_BIT(4),
-	BasicFlag_Pointer     = GB_BIT(5),
-	BasicFlag_String      = GB_BIT(6),
-	BasicFlag_Rune        = GB_BIT(7),
-	BasicFlag_Untyped     = GB_BIT(8),
+	BasicFlag_Quaternion  = GB_BIT(5),
+	BasicFlag_Pointer     = GB_BIT(6),
+	BasicFlag_String      = GB_BIT(7),
+	BasicFlag_Rune        = GB_BIT(8),
+	BasicFlag_Untyped     = GB_BIT(9),
 
-	BasicFlag_LLVM        = GB_BIT(10),
+	BasicFlag_LLVM        = GB_BIT(11),
 
 	BasicFlag_EndianLittle = GB_BIT(13),
 	BasicFlag_EndianBig    = GB_BIT(14),
 
-	BasicFlag_Numeric        = BasicFlag_Integer | BasicFlag_Float   | BasicFlag_Complex,
+	BasicFlag_Numeric        = BasicFlag_Integer | BasicFlag_Float   | BasicFlag_Complex | BasicFlag_Quaternion,
 	BasicFlag_Ordered        = BasicFlag_Integer | BasicFlag_Float   | BasicFlag_String  | BasicFlag_Pointer | BasicFlag_Rune,
 	BasicFlag_OrderedNumeric = BasicFlag_Integer | BasicFlag_Float   | BasicFlag_Rune,
 	BasicFlag_ConstantType   = BasicFlag_Boolean | BasicFlag_Numeric | BasicFlag_String  | BasicFlag_Pointer | BasicFlag_Rune,
@@ -107,21 +112,23 @@ struct BasicType {
 
 struct TypeStruct {
 	Array<Entity *> fields;
-	Ast *node;
-	Scope *  scope;
-
-	Array<i64> offsets;
-	bool       are_offsets_set;
-	bool       are_offsets_being_processed;
-	bool       is_packed;
-	bool       is_raw_union;
-	bool       is_polymorphic;
-	bool       is_poly_specialized;
+	Array<String>   tags;
+	Array<i64>      offsets;
+	Ast *           node;
+	Scope *         scope;
+
 	Type *     polymorphic_params; // Type_Tuple
 	Type *     polymorphic_parent;
 
-	i64      custom_align; // NOTE(bill): Only used in structs at the moment
+	i64      custom_align;
 	Entity * names;
+
+	bool are_offsets_set;
+	bool are_offsets_being_processed;
+	bool is_packed;
+	bool is_raw_union;
+	bool is_polymorphic;
+	bool is_poly_specialized;
 };
 
 struct TypeUnion {
@@ -131,12 +138,11 @@ struct TypeUnion {
 	i64           variant_block_size;
 	i64           custom_align;
 	i64           tag_size;
+	Type *        polymorphic_params; // Type_Tuple
+	Type *        polymorphic_parent;
 	bool          no_nil;
-
-	bool       is_polymorphic;
-	bool       is_poly_specialized;
-	Type *     polymorphic_params; // Type_Tuple
-	Type *     polymorphic_parent;
+	bool          is_polymorphic;
+	bool          is_poly_specialized;
 };
 
 #define TYPE_KINDS                                        \
@@ -184,7 +190,9 @@ struct TypeUnion {
 	TYPE_KIND(Tuple, struct {                             \
 		Array<Entity *> variables; /* Entity_Variable */  \
 		Array<i64>      offsets;                          \
+		bool            are_offsets_being_processed;      \
 		bool            are_offsets_set;                  \
+		bool            is_packed;                        \
 	})                                                    \
 	TYPE_KIND(Proc, struct {                              \
 		Ast *node;                                        \
@@ -195,9 +203,9 @@ struct TypeUnion {
 		i32      result_count;                            \
 		Array<Type *> abi_compat_params;                  \
 		Type *   abi_compat_result_type;                  \
-		bool     return_by_pointer;                       \
-		bool     variadic;                                \
 		i32      variadic_index;                          \
+		bool     variadic;                                \
+		bool     abi_types_set;                           \
 		bool     require_results;                         \
 		bool     c_vararg;                                \
 		bool     is_polymorphic;                          \
@@ -205,6 +213,7 @@ struct TypeUnion {
 		bool     has_proc_default_values;                 \
 		bool     has_named_results;                       \
 		bool     diverging; /* no return */               \
+		bool     return_by_pointer;                       \
 		u64      tags;                                    \
 		isize    specialization_count;                    \
 		ProcCallingConvention calling_convention;         \
@@ -341,6 +350,9 @@ gb_global Type basic_types[] = {
 	{Type_Basic, {Basic_complex64,         BasicFlag_Complex,                          8, STR_LIT("complex64")}},
 	{Type_Basic, {Basic_complex128,        BasicFlag_Complex,                         16, STR_LIT("complex128")}},
 
+	{Type_Basic, {Basic_quaternion128,     BasicFlag_Quaternion,                      16, STR_LIT("quaternion128")}},
+	{Type_Basic, {Basic_quaternion256,     BasicFlag_Quaternion,                      32, STR_LIT("quaternion256")}},
+
 	{Type_Basic, {Basic_int,               BasicFlag_Integer,                         -1, STR_LIT("int")}},
 	{Type_Basic, {Basic_uint,              BasicFlag_Integer | BasicFlag_Unsigned,    -1, STR_LIT("uint")}},
 	{Type_Basic, {Basic_uintptr,           BasicFlag_Integer | BasicFlag_Unsigned,    -1, STR_LIT("uintptr")}},
@@ -376,6 +388,7 @@ gb_global Type basic_types[] = {
 	{Type_Basic, {Basic_UntypedInteger,    BasicFlag_Integer    | BasicFlag_Untyped,   0, STR_LIT("untyped integer")}},
 	{Type_Basic, {Basic_UntypedFloat,      BasicFlag_Float      | BasicFlag_Untyped,   0, STR_LIT("untyped float")}},
 	{Type_Basic, {Basic_UntypedComplex,    BasicFlag_Complex    | BasicFlag_Untyped,   0, STR_LIT("untyped complex")}},
+	{Type_Basic, {Basic_UntypedQuaternion, BasicFlag_Quaternion | BasicFlag_Untyped,   0, STR_LIT("untyped quaternion")}},
 	{Type_Basic, {Basic_UntypedString,     BasicFlag_String     | BasicFlag_Untyped,   0, STR_LIT("untyped string")}},
 	{Type_Basic, {Basic_UntypedRune,       BasicFlag_Integer    | BasicFlag_Untyped,   0, STR_LIT("untyped rune")}},
 	{Type_Basic, {Basic_UntypedNil,        BasicFlag_Untyped,                          0, STR_LIT("untyped nil")}},
@@ -411,6 +424,9 @@ gb_global Type *t_f64             = &basic_types[Basic_f64];
 gb_global Type *t_complex64       = &basic_types[Basic_complex64];
 gb_global Type *t_complex128      = &basic_types[Basic_complex128];
 
+gb_global Type *t_quaternion128   = &basic_types[Basic_quaternion128];
+gb_global Type *t_quaternion256   = &basic_types[Basic_quaternion256];
+
 gb_global Type *t_int             = &basic_types[Basic_int];
 gb_global Type *t_uint            = &basic_types[Basic_uint];
 gb_global Type *t_uintptr         = &basic_types[Basic_uintptr];
@@ -445,6 +461,7 @@ gb_global Type *t_untyped_bool       = &basic_types[Basic_UntypedBool];
 gb_global Type *t_untyped_integer    = &basic_types[Basic_UntypedInteger];
 gb_global Type *t_untyped_float      = &basic_types[Basic_UntypedFloat];
 gb_global Type *t_untyped_complex    = &basic_types[Basic_UntypedComplex];
+gb_global Type *t_untyped_quaternion = &basic_types[Basic_UntypedQuaternion];
 gb_global Type *t_untyped_string     = &basic_types[Basic_UntypedString];
 gb_global Type *t_untyped_rune       = &basic_types[Basic_UntypedRune];
 gb_global Type *t_untyped_nil        = &basic_types[Basic_UntypedNil];
@@ -471,6 +488,7 @@ gb_global Type *t_type_info_integer           = nullptr;
 gb_global Type *t_type_info_rune              = nullptr;
 gb_global Type *t_type_info_float             = nullptr;
 gb_global Type *t_type_info_complex           = nullptr;
+gb_global Type *t_type_info_quaternion        = nullptr;
 gb_global Type *t_type_info_any               = nullptr;
 gb_global Type *t_type_info_typeid            = nullptr;
 gb_global Type *t_type_info_string            = nullptr;
@@ -495,6 +513,7 @@ gb_global Type *t_type_info_integer_ptr       = nullptr;
 gb_global Type *t_type_info_rune_ptr          = nullptr;
 gb_global Type *t_type_info_float_ptr         = nullptr;
 gb_global Type *t_type_info_complex_ptr       = nullptr;
+gb_global Type *t_type_info_quaternion_ptr    = nullptr;
 gb_global Type *t_type_info_any_ptr           = nullptr;
 gb_global Type *t_type_info_typeid_ptr        = nullptr;
 gb_global Type *t_type_info_string_ptr        = nullptr;
@@ -535,8 +554,27 @@ i64      type_offset_of             (Type *t, i32 index);
 gbString type_to_string             (Type *type);
 void     init_map_internal_types(Type *type);
 Type *   bit_set_to_int(Type *t);
+bool are_types_identical(Type *x, Type *y);
 
 
+bool type_ptr_set_exists(PtrSet<Type *> *s, Type *t) {
+	if (ptr_set_exists(s, t)) {
+		return true;
+	}
+
+	// TODO(bill, 2019-10-05): This is very slow and it's probably a lot
+	// faster to cache types correctly
+	for_array(i, s->entries) {
+		Type *f = s->entries[i].ptr;
+		if (are_types_identical(t, f)) {
+			ptr_set_add(s, t);
+			return true;
+		}
+	}
+
+	return false;
+}
+
 Type *base_type(Type *t) {
 	for (;;) {
 		if (t == nullptr) {
@@ -923,6 +961,13 @@ bool is_type_complex(Type *t) {
 	}
 	return false;
 }
+bool is_type_quaternion(Type *t) {
+	t = core_type(t);
+	if (t->kind == Type_Basic) {
+		return (t->Basic.flags & BasicFlag_Quaternion) != 0;
+	}
+	return false;
+}
 bool is_type_f32(Type *t) {
 	t = core_type(t);
 	if (t->kind == Type_Basic) {
@@ -1037,14 +1082,40 @@ Type *core_array_type(Type *t) {
 	return t;
 }
 
+// NOTE(bill): type can be easily compared using memcmp
+bool is_type_simple_compare(Type *t) {
+	t = core_type(t);
+	switch (t->kind) {
+	case Type_Array:
+		return is_type_simple_compare(t->Array.elem);
+
+	case Type_Basic:
+		if (t->Basic.flags & (BasicFlag_Integer|BasicFlag_Float|BasicFlag_Complex|BasicFlag_Rune|BasicFlag_Pointer)) {
+			return true;
+		}
+		return false;
+
+	case Type_Pointer:
+	case Type_Proc:
+	case Type_BitSet:
+	case Type_BitField:
+		return true;
+	}
+
+	return false;
+}
+
 Type *base_complex_elem_type(Type *t) {
 	t = core_type(t);
-	if (is_type_complex(t)) {
+	if (t->kind == Type_Basic) {
 		switch (t->Basic.kind) {
-		// case Basic_complex32:      return t_f16;
-		case Basic_complex64:      return t_f32;
-		case Basic_complex128:     return t_f64;
-		case Basic_UntypedComplex: return t_untyped_float;
+		// case Basic_complex32:         return t_f16;
+		case Basic_complex64:         return t_f32;
+		case Basic_complex128:        return t_f64;
+		case Basic_quaternion128:     return t_f32;
+		case Basic_quaternion256:     return t_f64;
+		case Basic_UntypedComplex:    return t_untyped_float;
+		case Basic_UntypedQuaternion: return t_untyped_float;
 		}
 	}
 	GB_PANIC("Invalid complex type");
@@ -1099,12 +1170,11 @@ bool is_type_integer_endian_big(Type *t) {
 		return is_type_integer_endian_big(bit_set_to_int(t));
 	} else if (t->kind == Type_Pointer) {
 		return is_type_integer_endian_big(&basic_types[Basic_uintptr]);
-	} else {
-		GB_PANIC("Unsupported type: %s", type_to_string(t));
 	}
 	return build_context.endian_kind == TargetEndian_Big;
 }
 
+
 bool is_type_integer_endian_little(Type *t) {
 	t = core_type(t);
 	if (t->kind == Type_Basic) {
@@ -1118,11 +1188,24 @@ bool is_type_integer_endian_little(Type *t) {
 		return is_type_integer_endian_little(bit_set_to_int(t));
 	} else if (t->kind == Type_Pointer) {
 		return is_type_integer_endian_little(&basic_types[Basic_uintptr]);
-	} else {
-		GB_PANIC("Unsupported type: %s", type_to_string(t));
 	}
 	return build_context.endian_kind == TargetEndian_Little;
 }
+bool is_type_endian_big(Type *t) {
+	return is_type_integer_endian_big(t);
+}
+bool is_type_endian_little(Type *t) {
+	return is_type_integer_endian_little(t);
+}
+
+bool is_type_dereferenceable(Type *t) {
+	if (is_type_rawptr(t)) {
+		return false;
+	}
+	return is_type_pointer(t);
+}
+
+
 
 bool is_type_different_to_arch_endianness(Type *t) {
 	switch (build_context.endian_kind) {
@@ -1284,6 +1367,19 @@ bool is_type_indexable(Type *t) {
 	return false;
 }
 
+bool is_type_sliceable(Type *t) {
+	Type *bt = base_type(t);
+	switch (bt->kind) {
+	case Type_Basic:
+		return bt->Basic.kind == Basic_string;
+	case Type_Array:
+	case Type_Slice:
+	case Type_DynamicArray:
+		return true;
+	}
+	return false;
+}
+
 
 bool is_type_polymorphic_record(Type *t) {
 	t = base_type(t);
@@ -1663,6 +1759,12 @@ bool are_types_identical(Type *x, Type *y) {
 					if (xf_is_using ^ yf_is_using) {
 						return false;
 					}
+					if (x->Struct.tags.count != y->Struct.tags.count) {
+						return false;
+					}
+					if (x->Struct.tags.count > 0 && x->Struct.tags[i] != y->Struct.tags[i]) {
+						return false;
+					}
 				}
 				return true;
 			}
@@ -1683,7 +1785,8 @@ bool are_types_identical(Type *x, Type *y) {
 
 	case Type_Tuple:
 		if (y->kind == Type_Tuple) {
-			if (x->Tuple.variables.count == y->Tuple.variables.count) {
+			if (x->Tuple.variables.count == y->Tuple.variables.count &&
+			    x->Tuple.is_packed == y->Tuple.is_packed) {
 				for_array(i, x->Tuple.variables) {
 					Entity *xe = x->Tuple.variables[i];
 					Entity *ye = y->Tuple.variables[i];
@@ -1763,6 +1866,7 @@ Type *default_type(Type *type) {
 		case Basic_UntypedInteger:    return t_int;
 		case Basic_UntypedFloat:      return t_f64;
 		case Basic_UntypedComplex:    return t_complex128;
+		case Basic_UntypedQuaternion: return t_quaternion256;
 		case Basic_UntypedString:     return t_string;
 		case Basic_UntypedRune:       return t_rune;
 		}
@@ -2131,19 +2235,22 @@ Selection lookup_field_with_selection(Type *type_, String field_name, bool is_ty
 		if (type->Array.count <= 4) {
 			// HACK(bill): Memory leak
 			switch (type->Array.count) {
-			#define _ARRAY_FIELD_CASE(_length, _name) \
-			case (_length): \
-				if (field_name == _name) { \
+			#define _ARRAY_FIELD_CASE_IF(_length, _name) \
+				if (field_name == (_name)) { \
 					selection_add_index(&sel, (_length)-1); \
 					sel.entity = alloc_entity_array_elem(nullptr, make_token_ident(str_lit(_name)), type->Array.elem, (_length)-1); \
 					return sel; \
-				} \
+				}
+			#define _ARRAY_FIELD_CASE(_length, _name0, _name1) \
+			case (_length): \
+				_ARRAY_FIELD_CASE_IF(_length, _name0); \
+				_ARRAY_FIELD_CASE_IF(_length, _name1); \
 				/*fallthrough*/
 
-			_ARRAY_FIELD_CASE(4, "w");
-			_ARRAY_FIELD_CASE(3, "z");
-			_ARRAY_FIELD_CASE(2, "y");
-			_ARRAY_FIELD_CASE(1, "x");
+			_ARRAY_FIELD_CASE(4, "w", "a");
+			_ARRAY_FIELD_CASE(3, "z", "b");
+			_ARRAY_FIELD_CASE(2, "y", "g");
+			_ARRAY_FIELD_CASE(1, "x", "r");
 			default: break;
 
 			#undef _ARRAY_FIELD_CASE
@@ -2254,7 +2361,9 @@ i64 type_size_of(Type *t) {
 		return 0;
 	}
 	// NOTE(bill): Always calculate the size when it is a Type_Basic
-	if (t->kind != Type_Basic && t->cached_size >= 0) {
+	if (t->kind == Type_Named && t->cached_size >= 0) {
+
+	} else if (t->kind != Type_Basic && t->cached_size >= 0) {
 		return t->cached_size;
 	}
 	TypePath path = {0};
@@ -2269,7 +2378,9 @@ i64 type_align_of(Type *t) {
 		return 1;
 	}
 	// NOTE(bill): Always calculate the size when it is a Type_Basic
-	if (t->kind != Type_Basic && t->cached_align > 0) {
+	if (t->kind == Type_Named && t->cached_align >= 0) {
+
+	} if (t->kind != Type_Basic && t->cached_align > 0) {
 		return t->cached_align;
 	}
 
@@ -2303,6 +2414,8 @@ i64 type_align_of_internal(Type *t, TypePath *path) {
 
 		case Basic_complex64: case Basic_complex128:
 			return type_size_of_internal(t, path) / 2;
+		case Basic_quaternion128: case Basic_quaternion256:
+			return type_size_of_internal(t, path) / 4;
 		}
 	} break;
 
@@ -2488,9 +2601,9 @@ bool type_set_offsets(Type *t) {
 		}
 	} else if (is_type_tuple(t)) {
 		if (!t->Tuple.are_offsets_set) {
-			t->Struct.are_offsets_being_processed = true;
-			t->Tuple.offsets = type_set_offsets_of(t->Tuple.variables, false, false);
-			t->Struct.are_offsets_being_processed = false;
+			t->Tuple.are_offsets_being_processed = true;
+			t->Tuple.offsets = type_set_offsets_of(t->Tuple.variables, t->Tuple.is_packed, false);
+			t->Tuple.are_offsets_being_processed = false;
 			t->Tuple.are_offsets_set = true;
 			return true;
 		}
@@ -2913,35 +3026,54 @@ gbString write_type_to_string(gbString str, Type *type) {
 			isize comma_index = 0;
 			for_array(i, type->Tuple.variables) {
 				Entity *var = type->Tuple.variables[i];
-				if (var != nullptr) {
-					if (var->kind == Entity_Constant) {
-						// Ignore
-						continue;
+				if (var == nullptr) {
+					continue;
+				}
+				String name = var->token.string;
+				if (var->kind == Entity_Constant) {
+					str = gb_string_appendc(str, "$");
+					str = gb_string_append_length(str, name.text, name.len);
+					if (!is_type_untyped(var->type)) {
+						str = gb_string_appendc(str, ": ");
+						str = write_type_to_string(str, var->type);
+						str = gb_string_appendc(str, " = ");
+						str = write_exact_value_to_string(str, var->Constant.value);
+					} else {
+						str = gb_string_appendc(str, "=");
+						str = write_exact_value_to_string(str, var->Constant.value);
 					}
+					continue;
+				}
 
-					if (comma_index++ > 0) {
-						str = gb_string_appendc(str, ", ");
-					}
+				if (comma_index++ > 0) {
+					str = gb_string_appendc(str, ", ");
+				}
 
-					if (var->kind == Entity_Variable) {
-						if (var->flags&EntityFlag_CVarArg) {
-							str = gb_string_appendc(str, "#c_vararg ");
-						}
-						if (var->flags&EntityFlag_Ellipsis) {
-							Type *slice = base_type(var->type);
-							str = gb_string_appendc(str, "..");
-							GB_ASSERT(var->type->kind == Type_Slice);
-							str = write_type_to_string(str, slice->Slice.elem);
-						} else {
-							str = write_type_to_string(str, var->type);
-						}
+				if (var->kind == Entity_Variable) {
+					if (var->flags&EntityFlag_CVarArg) {
+						str = gb_string_appendc(str, "#c_vararg ");
+					}
+					if (var->flags&EntityFlag_Ellipsis) {
+						Type *slice = base_type(var->type);
+						str = gb_string_appendc(str, "..");
+						GB_ASSERT(var->type->kind == Type_Slice);
+						str = write_type_to_string(str, slice->Slice.elem);
+					} else {
+						str = write_type_to_string(str, var->type);
+					}
+				} else {
+					GB_ASSERT(var->kind == Entity_TypeName);
+					if (var->type->kind == Type_Generic) {
+						str = gb_string_appendc(str, "typeid/");
+						str = write_type_to_string(str, var->type);
 					} else {
-						GB_ASSERT(var->kind == Entity_TypeName);
-						if (var->type->kind == Type_Generic) {
-							str = gb_string_appendc(str, "type/");
+						if (var->kind == Entity_TypeName) {
+							str = gb_string_appendc(str, "$");
+							str = gb_string_append_length(str, name.text, name.len);
+							str = gb_string_appendc(str, "=");
 							str = write_type_to_string(str, var->type);
 						} else {
-							str = gb_string_appendc(str, "type");
+							str = gb_string_appendc(str, "typeid");
 						}
 					}
 				}
diff --git a/src/unicode.cpp b/src/unicode.cpp
index 0ad658806..679d56365 100644
--- a/src/unicode.cpp
+++ b/src/unicode.cpp
@@ -2,7 +2,6 @@
 #pragma warning(disable: 4245)
 
 extern "C" {
-#include "utf8proc/utf8proc.h"
 #include "utf8proc/utf8proc.c"
 }
 #pragma warning(pop)
diff --git a/src/utf8proc/utf8proc.c b/src/utf8proc/utf8proc.c
index e821889c6..29fc250fc 100644
--- a/src/utf8proc/utf8proc.c
+++ b/src/utf8proc/utf8proc.c
@@ -40,7 +40,6 @@
  *  Implementation of libutf8proc.
  */
 
-
 #include "utf8proc.h"
 #include "utf8proc_data.c"