### 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.
parser->push_warning(p_local, GDScriptWarning::SHADOWED_VARIABLE, p_context, p_local->name, base_class->get_member(name).get_type_name(), itos(base_class->get_member(name).get_line()));
			return true;
		}
		base_class = base_class->base_type.class_type;
	}
	StringName parent = base.native_type;
	while (parent != StringName()) {
		ERR_FAIL_COND_V_MSG(!class_exists(parent), false, "Non-existent native base class.");
		if (ClassDB::has_method(parent, name, true)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_VARIABLE_BASE_CLASS, p_context, p_local->name, "method", parent);
			return true;
		} else if (ClassDB::has_signal(parent, name, true)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_VARIABLE_BASE_CLASS, p_context, p_local->name, "signal", parent);
			return true;
		} else if (ClassDB::has_property(parent, name, true)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_VARIABLE_BASE_CLASS, p_context, p_local->name, "property", parent);
			return true;
		} else if (ClassDB::has_integer_constant(parent, name, true)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_VARIABLE_BASE_CLASS, p_context, p_local->name, "constant", parent);
			return true;
		} else if (ClassDB::has_enum(parent, name, true)) {
			parser->push_warning(p_local, GDScriptWarning::SHADOWED_VARIABLE_BASE_CLASS, p_context, p_local->name, "enum", parent);
			return true;
		}
		parent = ClassDB::get_parent_class(parent);
	}
	return false;
}
#endif
GDScriptParser::DataType GDScriptAnalyzer::get_operation_type(Variant::Operator p_operation, const GDScriptParser::DataType &p_a, bool &r_valid, const GDScriptParser::Node *p_source) {