### 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.
result = make_script_meta_type(member.constant->initializer->reduced_value);
							}
							found = true;
							break;
						}
						[[fallthrough]];
					default:
						push_error(vformat(R"("%s" is a %s but does not contain a type.)", first, member.get_type_name()), p_type);
						return bad_type;
				}
			}
		}
	}
	if (!result.is_set()) {
		push_error(vformat(R"("%s" was not found in the current scope.)", first), p_type);
		return bad_type;
	}
	if (p_type->type_chain.size() > 1) {
		if (result.kind == GDScriptParser::DataType::CLASS) {
			for (int i = 1; i < p_type->type_chain.size(); i++) {
				GDScriptParser::DataType base = result;
				reduce_identifier_from_base(p_type->type_chain[i], &base);
				result = p_type->type_chain[i]->get_datatype();
				if (!result.is_set()) {
					push_error(vformat(R"(Could not find type "%s" under base "%s".)", p_type->type_chain[i]->name, base.to_string()), p_type->type_chain[1]);
					return bad_type;
				} else if (!result.is_meta_type) {
					push_error(vformat(R"(Member "%s" under base "%s" is not a valid type.)", p_type->type_chain[i]->name, base.to_string()), p_type->type_chain[1]);
					return bad_type;
				}