### 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.
break;
					case Callable::CallError::CALL_ERROR_TOO_FEW_ARGUMENTS:
						push_error(vformat(R"(Too few arguments for %s constructor. Received %d but expected %d.)", Variant::get_type_name(builtin_type), p_call->arguments.size(), err.expected), p_call);
						break;
					case Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL:
					case Callable::CallError::CALL_ERROR_METHOD_NOT_CONST:
						break; 
					case Callable::CallError::CALL_OK:
						p_call->is_constant = true;
						p_call->reduced_value = value;
						break;
				}
			} else {
				
				
				if (p_call->arguments.size() == 1) {
					GDScriptParser::DataType arg_type = p_call->arguments[0]->get_datatype();
					if (arg_type.is_variant()) {
						mark_node_unsafe(p_call->arguments[0]);
					} else {
						if (arg_type.kind == GDScriptParser::DataType::BUILTIN && arg_type.builtin_type == builtin_type) {
							
							p_call->set_datatype(call_type);
							return;
						}
					}
				}
				List<MethodInfo> constructors;
				Variant::get_constructor_list(builtin_type, &constructors);
				bool match = false;