GDScript: Fix handling of scope for local variables

modules/gdscript/gdscript_compiler.h

@@ -51,12 +51,11 @@ class GDScriptCompiler {
 		GDScriptCodeGenerator *generator = nullptr;
 		Map<StringName, GDScriptCodeGenerator::Address> parameters;
 		Map<StringName, GDScriptCodeGenerator::Address> locals;
-		List<Set<StringName>> locals_in_scope;
+		List<Map<StringName, GDScriptCodeGenerator::Address>> locals_stack;
 
 		GDScriptCodeGenerator::Address add_local(const StringName &p_name, const GDScriptDataType &p_type) {
 			uint32_t addr = generator->add_local(p_name, p_type);
 			locals[p_name] = GDScriptCodeGenerator::Address(GDScriptCodeGenerator::Address::LOCAL_VARIABLE, addr, p_type);
-			locals_in_scope.back()->get().insert(p_name);
 			return locals[p_name];
 		}
 
@@ -102,17 +101,14 @@ class GDScriptCompiler {
 		}
 
 		void start_block() {
-			Set<StringName> scope;
-			locals_in_scope.push_back(scope);
+			Map<StringName, GDScriptCodeGenerator::Address> old_locals = locals;
+			locals_stack.push_back(old_locals);
 			generator->start_block();
 		}
 
 		void end_block() {
-			Set<StringName> &scope = locals_in_scope.back()->get();
-			for (Set<StringName>::Element *E = scope.front(); E; E = E->next()) {
-				locals.erase(E->get());
-			}
-			locals_in_scope.pop_back();
+			locals = locals_stack.back()->get();
+			locals_stack.pop_back();
 			generator->end_block();
 		}
 	};