Merge pull request #5654 from smoke-y/procType

Fix compiler segfault when trying to use proc at type level

src/check_expr.cpp

@@ -7947,7 +7947,7 @@ gb_internal CallArgumentError check_polymorphic_record_type(CheckerContext *c, O
 				s = gb_string_append_fmt(s, "$%.*s", LIT(name));
 
 				if (v->kind == Entity_TypeName) {
-					if (v->type->kind != Type_Generic) {
+					if (v->type != nullptr && v->type->kind != Type_Generic) {
 						s = gb_string_append_fmt(s, "=");
 						s = write_type_to_string(s, v->type, false);
 					}