### 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.
const StringName &name = p_local->name;
	GDScriptParser::DataType base = parser->current_class->get_datatype();
	GDScriptParser::ClassNode *base_class = base.class_type;
	{
		List<MethodInfo> gdscript_funcs;
		GDScriptLanguage::get_singleton()->get_public_functions(&gdscript_funcs);
		for (MethodInfo &info : gdscript_funcs) {
			if (info.name == name) {
				parser->push_warning(p_local, GDScriptWarning::SHADOWED_GLOBAL_IDENTIFIER, p_context, name, "built-in function");
				return true;
			}
		}
		if (Variant::has_utility_function(name)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_GLOBAL_IDENTIFIER, p_context, name, "built-in function");
			return true;
		} else if (ClassDB::class_exists(name)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_GLOBAL_IDENTIFIER, p_context, name, "global class");
			return true;
		}
	}
	while (base_class != nullptr) {
		if (base_class->has_member(name)) {