### 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.
member.constant->set_datatype(resolving_datatype);
				resolve_constant(member.constant, false);
				
				for (GDScriptParser::AnnotationNode *&E : member.constant->annotations) {
					resolve_annotation(E);
					E->apply(parser, member.constant);
				}
			} break;
			case GDScriptParser::ClassNode::Member::SIGNAL: {
				check_class_member_name_conflict(p_class, member.signal->identifier->name, member.signal);
				member.signal->set_datatype(resolving_datatype);
				
				
				MethodInfo mi = MethodInfo(member.signal->identifier->name);
				for (int j = 0; j < member.signal->parameters.size(); j++) {
					GDScriptParser::ParameterNode *param = member.signal->parameters[j];
					GDScriptParser::DataType param_type = type_from_metatype(resolve_datatype(param->datatype_specifier));
					param->set_datatype(param_type);
					mi.arguments.push_back(PropertyInfo(param_type.builtin_type, param->identifier->name));
					
				}
				member.signal->set_datatype(make_signal_type(mi));
				
				for (GDScriptParser::AnnotationNode *&E : member.signal->annotations) {
					resolve_annotation(E);
					E->apply(parser, member.signal);
				}
			} break;
			case GDScriptParser::ClassNode::Member::ENUM: {
				check_class_member_name_conflict(p_class, member.m_enum->identifier->name, member.m_enum);