diff --git a/src/type_checker.odin b/src/type_checker.odin
index 8782951..f338bb8 100644
--- a/src/type_checker.odin
+++ b/src/type_checker.odin
@@ -107,7 +107,8 @@ ast_to_type :: proc(node: ^Node) -> ^Type {
 			if res != nil {
 				return type_create_struct(value)
 			}
-			fmt.panicf("Unhandled identifier in ast_to_type: %s", value)
+			append(&g_message_list, message_create(.Error, fmt.aprintf("Unknown type: %s", value), node.range))
+			return nil
 		}
 	} else if node.kind == .Pointer {
 		return type_create_pointer(ast_to_type(node.children[0]))
@@ -548,6 +549,15 @@ type_check :: proc(ast: ^Node, parent_ast: ^Node) {
 		)
 		ast.return_type = ast_to_type(ast.children[1])
 	case .VariableDeclaration:
+		name_sum := get_character_sum_of_dyn_arr(&ast.children[0].value.([dynamic]u8))
+		if name_sum in scope_stack[len(scope_stack) - 1].variable_definitions {
+			append(
+				&g_message_list,
+				message_create(.Error, "A variable is already declared with the same name", ast.range),
+			)
+			return
+		}
+
 		if ast.children[2] != nil {
 			type_check(ast.children[2], ast)
 			if ast.children[1] == nil {
@@ -568,14 +578,14 @@ type_check :: proc(ast: ^Node, parent_ast: ^Node) {
 						ast.range,
 					),
 				)
+				return
 			}
 		} else {
 			ast.return_type = ast_to_type(ast.children[1])
 		}
-		scope_stack[len(scope_stack) - 1].variable_definitions[get_character_sum_of_dyn_arr(&ast.children[0].value.([dynamic]u8))] =
-			ast.return_type
-		scope_stack[len(scope_stack) - 1].variable_mutability_definitions[get_character_sum_of_dyn_arr(&ast.children[0].value.([dynamic]u8))] =
-		!ast.value.(bool)
+
+		scope_stack[len(scope_stack) - 1].variable_definitions[name_sum] = ast.return_type
+		scope_stack[len(scope_stack) - 1].variable_mutability_definitions[name_sum] = !ast.value.(bool)
 	case .If:
 		type_check(ast.children[0], ast)
 		if ast.children[0].return_type == nil || ast.children[0].return_type.kind != .Integer {