Incorrect handling when reporting fn with optional compile time type #2862

releasenotes.md

@@ -140,6 +140,7 @@
 - Crash when creating `$Type*` where `$Type` is an optional type #2848
 - Crashes when using `io::EOF~!` in various unhandled places. #2848
 - Crash when trying to create a const zero untyped list #2847
+- Incorrect handling when reporting fn with optional compile time type #2862
 
 ### Stdlib changes
 - Add `ThreadPool` join function to wait for all threads to finish in the pool without destroying the threads.

src/compiler/compiler_internal.h

@@ -3095,6 +3095,8 @@ INLINE const char *type_invalid_storage_type_name(Type *type)
 			return "a typeinfo";
 		case TYPE_WILDCARD:
 			return "an empty value";
+		case TYPE_OPTIONAL:
+			return "an optional with a compile time type";
 		default:
 			UNREACHABLE;
 	}

test/test_suite/expressions/optional_untyped_list_return.c3

@@ -0,0 +1,6 @@
+fn $typeof({})? foo() {} // #error: A function may not return an optional with a compile time type, only macros may do
+
+fn int main()
+{
+	return 0;
+}