### 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.
if (p_a.kind == GDScriptParser::DataType::ENUM) {
		if (p_a.is_meta_type) {
			a_type = Variant::DICTIONARY;
		} else {
			a_type = Variant::INT;
		}
	}
	if (p_b.kind == GDScriptParser::DataType::ENUM) {
		if (p_b.is_meta_type) {
			b_type = Variant::DICTIONARY;
		} else {
			b_type = Variant::INT;
		}
	}
	Variant::ValidatedOperatorEvaluator op_eval = Variant::get_validated_operator_evaluator(p_operation, a_type, b_type);
	bool hard_operation = p_a.is_hard_type() && p_b.is_hard_type();
	bool validated = op_eval != nullptr;
	GDScriptParser::DataType result;
	if (validated) {
		r_valid = true;
		result.type_source = hard_operation ? GDScriptParser::DataType::ANNOTATED_INFERRED : GDScriptParser::DataType::INFERRED;
		result.kind = GDScriptParser::DataType::BUILTIN;
		result.builtin_type = Variant::get_operator_return_type(p_operation, a_type, b_type);
	} else {
		r_valid = !hard_operation;
		result.kind = GDScriptParser::DataType::VARIANT;
	}
	return result;
}
bool GDScriptAnalyzer::is_type_compatible(const GDScriptParser::DataType &p_target, const GDScriptParser::DataType &p_source, bool p_allow_implicit_conversion, const GDScriptParser::Node *p_source_node) {