### 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.
p_function->set_datatype(resolving_datatype);
#ifdef TOOLS_ENABLED
	int default_value_count = 0;
#endif 
	for (int i = 0; i < p_function->parameters.size(); i++) {
		resolve_parameter(p_function->parameters[i]);
#ifdef DEBUG_ENABLED
		if (p_function->parameters[i]->usages == 0 && !String(p_function->parameters[i]->identifier->name).begins_with("_")) {
			parser->push_warning(p_function->parameters[i]->identifier, GDScriptWarning::UNUSED_PARAMETER, function_name, p_function->parameters[i]->identifier->name);
		}
		is_shadowing(p_function->parameters[i]->identifier, "function parameter");
#endif 
#ifdef TOOLS_ENABLED
		if (p_function->parameters[i]->initializer) {
			default_value_count++;
			if (p_function->parameters[i]->initializer->is_constant) {
				p_function->default_arg_values.push_back(p_function->parameters[i]->initializer->reduced_value);
			} else {
				p_function->default_arg_values.push_back(Variant()); 
			}
		}
#endif 
	}
	if (!p_is_lambda && function_name == GDScriptLanguage::get_singleton()->strings._init) {
		
		GDScriptParser::DataType return_type = parser->current_class->get_datatype();
		return_type.is_meta_type = false;
		p_function->set_datatype(return_type);
		if (p_function->return_type) {
			GDScriptParser::DataType declared_return = resolve_datatype(p_function->return_type);