### 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_identifier->source == GDScriptParser::IdentifierNode::UNDEFINED_SOURCE || p_identifier->source == GDScriptParser::IdentifierNode::MEMBER_CONSTANT) {
				return;
			}
			GDScriptParser::FunctionNode *function_test = lambda_stack.back()->get()->function;
			
			
			while (function_test != nullptr && function_test != p_identifier->source_function && function_test->source_lambda != nullptr && !function_test->source_lambda->captures_indices.has(p_identifier->name)) {
				function_test->source_lambda->captures_indices[p_identifier->name] = function_test->source_lambda->captures.size();
				function_test->source_lambda->captures.push_back(p_identifier);
				function_test = function_test->source_lambda->parent_function;
			}
		}
		return;
	}
	StringName name = p_identifier->name;
	p_identifier->source = GDScriptParser::IdentifierNode::UNDEFINED_SOURCE;
	
	
	Variant::Type builtin_type = GDScriptParser::get_builtin_type(name);
	if (builtin_type != Variant::OBJECT && builtin_type < Variant::VARIANT_MAX) {
		if (can_be_builtin) {
			p_identifier->set_datatype(make_builtin_meta_type(builtin_type));
			return;
		} else {
			push_error(R"(Builtin type cannot be used as a name on its own.)", p_identifier);
		}
	}
	if (class_exists(name)) {
		p_identifier->set_datatype(make_native_meta_type(name));
		return;