Implement `#complete switch` by default, replace with `#partial switch` #511

3 files changed, 56 insertions, 47 deletions

diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index 7d5648018..7bb6924b4 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -807,12 +807,11 @@ void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 		}
 	}
 
-	bool complete = ss->complete;
+	bool is_partial = ss->partial;
 
-	if (complete) {
+	if (is_partial) {
 		if (!is_type_enum(x.type)) {
-			error(x.expr, "#complete switch statement can be only used with an enum type");
-			complete = false;
+			error(x.expr, "#partial switch statement can be only used with an enum type");
 		}
 	}
 
@@ -877,9 +876,6 @@ void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 				Operand a1 = lhs;
 				Operand b1 = rhs;
 				check_comparison(ctx, &a1, &b1, Token_LtEq);
-				if (complete) {
-					error(lhs.expr, "#complete switch statement does not allow ranges");
-				}
 
 				add_constant_switch_case(ctx, &seen, lhs);
 				if (upper_op == Token_GtEq) {
@@ -926,9 +922,6 @@ void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 						continue;
 					}
 					if (y.mode != Addressing_Constant) {
-						if (complete) {
-							error(y.expr, "#complete switch statement only allows constant case clauses");
-						}
 						continue;
 					}
 
@@ -942,7 +935,7 @@ void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 		check_close_scope(ctx);
 	}
 
-	if (complete) {
+	if (!is_partial && is_type_enum(x.type)) {
 		Type *et = base_type(x.type);
 		GB_ASSERT(is_type_enum(et));
 		auto fields = et->Enum.fields;
@@ -968,18 +961,17 @@ void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 			defer (begin_error_block());
 
 			if (unhandled.count == 1) {
-				error_no_newline(node, "Unhandled switch case: ");
+				error_no_newline(node, "Unhandled switch case: %.*s", LIT(unhandled[0]->token.string));
 			} else {
 				error_no_newline(node, "Unhandled switch cases: ");
-			}
-			for_array(i, unhandled) {
-				Entity *f = unhandled[i];
-				if (i > 0)  {
-					error_line(", ");
+				for_array(i, unhandled) {
+					Entity *f = unhandled[i];
+					error_line("\t%.*s\n", LIT(f->token.string));
 				}
-				error_line("%.*s", LIT(f->token.string));
 			}
 			error_line("\n");
+
+			error_line("\tSuggestion: Was '#partial switch' wanted? This replaces the previous '#complete switch'.\n");
 		}
 	}
 }
@@ -1042,11 +1034,10 @@ void check_type_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 		return;
 	}
 
-	bool complete = ss->complete;
-	if (complete) {
+	bool is_partial = ss->partial;
+	if (is_partial) {
 		if (switch_kind != TypeSwitch_Union) {
-			error(node, "#complete switch statement may only be used with a union");
-			complete = false;
+			error(node, "#partial switch statement may only be used with a union");
 		}
 	}
 
@@ -1174,7 +1165,7 @@ void check_type_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 		check_close_scope(ctx);
 	}
 
-	if (complete) {
+	if (!is_partial && is_type_union(type_deref(x.type))) {
 		Type *ut = base_type(type_deref(x.type));
 		GB_ASSERT(is_type_union(ut));
 		auto variants = ut->Union.variants;
@@ -1191,20 +1182,20 @@ void check_type_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 
 		if (unhandled.count > 0) {
 			if (unhandled.count == 1) {
-				error_no_newline(node, "Unhandled switch case: ");
+				gbString s = type_to_string(unhandled[0]);
+				error_no_newline(node, "Unhandled switch case: %s", s);
+				gb_string_free(s);
 			} else {
-				error_no_newline(node, "Unhandled switch cases: ");
-			}
-			for_array(i, unhandled) {
-				Type *t = unhandled[i];
-				if (i > 0)  {
-					error_line(", ");
+				error_no_newline(node, "Unhandled switch cases:\n");
+				for_array(i, unhandled) {
+					Type *t = unhandled[i];
+					gbString s = type_to_string(t);
+					error_line("\t%s\n", s);
+					gb_string_free(s);
 				}
-				gbString s = type_to_string(t);
-				error_line("%s", s);
-				gb_string_free(s);
 			}
 			error_line("\n");
+			error_line("\tSuggestion: Was '#partial switch' wanted? This replaces the previous '#complete switch'.\n");
 		}
 	}
 }
diff --git a/src/parser.cpp b/src/parser.cpp
index fbbb9e1cb..0e9b20e52 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -766,6 +766,7 @@ Ast *ast_switch_stmt(AstFile *f, Token token, Ast *init, Ast *tag, Ast *body) {
 	result->SwitchStmt.init  = init;
 	result->SwitchStmt.tag   = tag;
 	result->SwitchStmt.body  = body;
+	result->SwitchStmt.partial = false;
 	return result;
 }
 
@@ -775,6 +776,7 @@ Ast *ast_type_switch_stmt(AstFile *f, Token token, Ast *tag, Ast *body) {
 	result->TypeSwitchStmt.token = token;
 	result->TypeSwitchStmt.tag   = tag;
 	result->TypeSwitchStmt.body  = body;
+	result->TypeSwitchStmt.partial = false;
 	return result;
 }
 
@@ -4060,16 +4062,32 @@ Ast *parse_stmt(AstFile *f) {
 			s = parse_stmt(f);
 			switch (s->kind) {
 			case Ast_SwitchStmt:
-				s->SwitchStmt.complete = true;
+				s->SwitchStmt.partial = false;
+				syntax_warning(token, "#complete is now the default and has been replaced with its opposite: #partial");
 				break;
 			case Ast_TypeSwitchStmt:
-				s->TypeSwitchStmt.complete = true;
+				s->TypeSwitchStmt.partial = false;
+				syntax_warning(token, "#complete is now the default and has been replaced with its opposite: #partial");
 				break;
 			default:
 				syntax_error(token, "#complete can only be applied to a switch statement");
 				break;
 			}
 			return s;
+		} else if (tag == "partial") {
+			s = parse_stmt(f);
+			switch (s->kind) {
+			case Ast_SwitchStmt:
+				s->SwitchStmt.partial = true;
+				break;
+			case Ast_TypeSwitchStmt:
+				s->TypeSwitchStmt.partial = true;
+				break;
+			default:
+				syntax_error(token, "#partial can only be applied to a switch statement");
+				break;
+			}
+			return s;
 		} else if (tag == "assert") {
 			Ast *t = ast_basic_directive(f, hash_token, tag);
 			return ast_expr_stmt(f, parse_call_expr(f, t));
diff --git a/src/parser.hpp b/src/parser.hpp
index 7101e0247..983db1042 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -363,20 +363,20 @@ AST_KIND(_ComplexStmtBegin, "", bool) \
 		Entity *implicit_entity; \
 	}) \
 	AST_KIND(SwitchStmt, "switch statement", struct { \
-		Token token;    \
-		Ast *label;    \
-		Ast *init;     \
-		Ast *tag;      \
-		Ast *body;     \
-		bool complete; \
+		Token token;  \
+		Ast *label;   \
+		Ast *init;    \
+		Ast *tag;     \
+		Ast *body;    \
+		bool partial; \
 	}) \
 	AST_KIND(TypeSwitchStmt, "type switch statement", struct { \
-		Token token;   \
-		Ast *label;    \
-		Ast *tag;      \
-		Ast *body;     \
-		bool complete; \
-	}) \
+		Token token; \
+		Ast *label;  \
+		Ast *tag;    \
+		Ast *body;   \
+		bool partial; \
+}) \
 	AST_KIND(DeferStmt,  "defer statement",  struct { Token token; Ast *stmt; }) \
 	AST_KIND(BranchStmt, "branch statement", struct { Token token; Ast *label; }) \
 	AST_KIND(UsingStmt,  "using statement",  struct { \