### Godot version

4.0 beta 10

### System information

Windows 10

### Issue description

Godot crashes when i accidently name 2 items in an enum the same

EDIT:
The editor freeze for some seconds, then both editor- and console-window dissapear

### Steps to reproduce

Write

```gdscript
enum {
    A,
}
```

and then add a second line with another A:

```gdscript
enum {
    A,
    A # <- crash
}
```

Does not always immediatly happen if i copy&paste items.
Does not happen when i change the script in another editor and open the script in Godot.

### Minimal reproduction project

[enum.zip](https://github.com/godotengine/godot/files/10313759/enum.zip)

if (has_expected_type && expected_type.is_hard_type() && expected_type.kind == GDScriptParser::DataType::BUILTIN && expected_type.builtin_type == Variant::NIL) {
			push_error("A void function cannot return a value.", p_return);
		}
		result = p_return->return_value->get_datatype();
	} else {
		
		result.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
		result.kind = GDScriptParser::DataType::BUILTIN;
		result.builtin_type = Variant::NIL;
		result.is_constant = true;
	}
	if (has_expected_type) {
		expected_type.is_meta_type = false;
		if (expected_type.is_hard_type()) {
			if (!is_type_compatible(expected_type, result)) {
				
				if (!is_type_compatible(result, expected_type)) {
					push_error(vformat(R"(Cannot return value of type "%s" because the function return type is "%s".)", result.to_string(), expected_type.to_string()), p_return);
				} else {
					
					mark_node_unsafe(p_return);
				}
#ifdef DEBUG_ENABLED
			} else if (expected_type.builtin_type == Variant::INT && result.builtin_type == Variant::FLOAT) {
				parser->push_warning(p_return, GDScriptWarning::NARROWING_CONVERSION);
			} else if (result.is_variant()) {
				mark_node_unsafe(p_return);
#endif
			}
		}