### 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)

result_type.kind = GDScriptParser::DataType::VARIANT;
				mark_node_unsafe(p_subscript);
			} else {
				if (base_type.kind == GDScriptParser::DataType::BUILTIN && !index_type.is_variant()) {
					
					bool error = index_type.kind != GDScriptParser::DataType::BUILTIN && base_type.builtin_type != Variant::DICTIONARY;
					if (!error) {
						switch (base_type.builtin_type) {
							
							case Variant::PACKED_BYTE_ARRAY:
							case Variant::PACKED_COLOR_ARRAY:
							case Variant::PACKED_FLOAT32_ARRAY:
							case Variant::PACKED_FLOAT64_ARRAY:
							case Variant::PACKED_INT32_ARRAY:
							case Variant::PACKED_INT64_ARRAY:
							case Variant::PACKED_STRING_ARRAY:
							case Variant::PACKED_VECTOR2_ARRAY:
							case Variant::PACKED_VECTOR3_ARRAY:
							case Variant::ARRAY:
							case Variant::STRING:
								error = index_type.builtin_type != Variant::INT && index_type.builtin_type != Variant::FLOAT;
								break;
							
							case Variant::RECT2:
							case Variant::RECT2I:
							case Variant::PLANE:
							case Variant::QUATERNION:
							case Variant::AABB:
							case Variant::OBJECT:
								error = index_type.builtin_type != Variant::STRING && index_type.builtin_type != Variant::STRING_NAME;