Fix `override_entity_in_scope `behaviour to correctly to report the changes upstream better

1 files changed, 27 insertions, 14 deletions

diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 51c0b6ee5..ea6c036cc 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -343,22 +343,36 @@ void override_entity_in_scope(Entity *original_entity, Entity *new_entity) {
 		return;
 	}
 
-	// IMPORTANT TODO(bill)
-	// Date: 2018-09-29
-	// This assert fails on `using import` if the name of the alias is the same. What should be the expected behaviour?
-	// Namespace collision or override? Overridding is the current behaviour
+	// IMPORTANT NOTE(bill, 2021-04-10): Overriding behaviour was flawed in that the
+	// original entity was still used check checked, but the checking was only
+	// relying on "constant" data such as the Entity.type and Entity.Constant.value
 	//
-	//     using import "foo"
-	//     bar :: foo.bar;
-
-	// GB_ASSERT_MSG(found_entity == original_entity, "%.*s == %.*s", LIT(found_entity->token.string), LIT(new_entity->token.string));
+	// Therefore two things can be done: the type can be assigned to state that it
+	// has been "evaluated" and the variant data can be copied across
 
 	string_map_set(&found_scope->elements, original_name, new_entity);
+
+	original_entity->type = new_entity->type;
+
+	if (original_entity->identifier == nullptr) {
+		original_entity->identifier = new_entity->identifier;
+	}
+	if (original_entity->identifier != nullptr &&
+	    original_entity->identifier->kind == Ast_Ident) {
+		original_entity->identifier->Ident.entity = new_entity;
+	}
+	original_entity->flags |= EntityFlag_Overridden;
+
+	// IMPORTANT NOTE(bill, 2021-04-10): copy only the variants
+	// This is most likely NEVER required, but it does not at all hurt to keep
+	isize offset = cast(u8 *)&original_entity->Dummy.start - cast(u8 *)original_entity;
+	isize size = gb_size_of(*original_entity) - offset;
+	gb_memmove(cast(u8 *)original_entity, cast(u8 *)new_entity, size);
 }
 
 
 
-void check_const_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init, Type *named_type) {
+void check_const_decl(CheckerContext *ctx, Entity *&e, Ast *type_expr, Ast *init, Type *named_type) {
 	GB_ASSERT(e->type == nullptr);
 	GB_ASSERT(e->kind == Entity_Constant);
 
@@ -374,6 +388,7 @@ void check_const_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init,
 
 	Operand operand = {};
 
+	Entity *other_entity = nullptr;
 	if (init != nullptr) {
 		Entity *entity = nullptr;
 		if (init->kind == Ast_Ident) {
@@ -412,7 +427,6 @@ void check_const_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init,
 			GB_ASSERT(operand.proc_group->kind == Entity_ProcGroup);
 			// NOTE(bill, 2020-06-10): It is better to just clone the contents than overriding the entity in the scope
 			// Thank goodness I made entities a tagged union to allow for this implace patching
-			// override_entity_in_scope(e, operand.proc_group);
 			e->kind = Entity_ProcGroup;
 			e->ProcGroup.entities = array_clone(heap_allocator(), operand.proc_group->ProcGroup.entities);
 			return;
@@ -454,7 +468,6 @@ void check_const_decl(CheckerContext *ctx, Entity *e, Ast *type_expr, Ast *init,
 							error(decl->attributes[0], "Constant alias declarations cannot have attributes");
 						}
 					}
-
 					return;
 				}
 			}
@@ -846,7 +859,7 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 	}
 }
 
-void check_global_variable_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);
 
@@ -946,7 +959,7 @@ void check_global_variable_decl(CheckerContext *ctx, Entity *e, Ast *type_expr,
 	check_init_variable(ctx, e, &o, str_lit("variable declaration"));
 }
 
-void check_proc_group_decl(CheckerContext *ctx, Entity *pg_entity, DeclInfo *d) {
+void check_proc_group_decl(CheckerContext *ctx, Entity *&pg_entity, DeclInfo *d) {
 	GB_ASSERT(pg_entity->kind == Entity_ProcGroup);
 	auto *pge = &pg_entity->ProcGroup;
 	String proc_group_name = pg_entity->token.string;
@@ -1074,7 +1087,7 @@ void check_proc_group_decl(CheckerContext *ctx, Entity *pg_entity, DeclInfo *d)
 
 }
 
-void check_entity_decl(CheckerContext *ctx, Entity *e, DeclInfo *d, Type *named_type) {
+void check_entity_decl(CheckerContext *ctx, Entity *&e, DeclInfo *d, Type *named_type) {
 	if (e->state == EntityState_Resolved)  {
 		return;
 	}