### Godot version

Beta 17, master

### System information

Windows 11

### Issue description

Godot gets a hard crash while attempting to code-complete for member `const` of a class.

### Steps to reproduce

```GDScript
enum E { V1 }

const e := E
```

And then type a `.` after the last `E`, which triggers code hints/auto-completion for subscripts based on `E` and causes a hard crash.

Does not happen for `var e := E.V1`.

### Minimal reproduction project

See above.
return ERR_PARSE_ERROR;
			}
			Error err = ext_parser->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
			if (err != OK) {
				push_error(vformat(R"(Could not resolve super class inheritance from "%s".)", p_class->extends_path), p_class);
				return err;
			}
			base = ext_parser->get_parser()->head->get_datatype();
		} else {
			if (p_class->extends.is_empty()) {
				push_error("Could not resolve an empty super class path.", p_class);
				return ERR_PARSE_ERROR;
			}
			const StringName &name = p_class->extends[extends_index++];
			base.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
			if (ScriptServer::is_global_class(name)) {
				String base_path = ScriptServer::get_global_class_path(name);
				if (base_path == parser->script_path) {
					base = parser->head->get_datatype();
				} else {
					Ref<GDScriptParserRef> base_parser = get_parser_for(base_path);
					if (base_parser.is_null()) {
						push_error(vformat(R"(Could not resolve super class "%s".)", name), p_class);
						return ERR_PARSE_ERROR;
					}
					Error err = base_parser->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
					if (err != OK) {
						push_error(vformat(R"(Could not resolve super class inheritance from "%s".)", name), p_class);
						return err;
					}