### 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)

GDScriptParser::Node *source = nullptr;
	switch (identifier->source) {
		case GDScriptParser::IdentifierNode::MEMBER_VARIABLE: {
			source = identifier->variable_source;
		} break;
		case GDScriptParser::IdentifierNode::FUNCTION_PARAMETER: {
			source = identifier->parameter_source;
		} break;
		case GDScriptParser::IdentifierNode::LOCAL_VARIABLE: {
			source = identifier->variable_source;
		} break;
		case GDScriptParser::IdentifierNode::LOCAL_ITERATOR: {
			source = identifier->bind_source;
		} break;
		default:
			break;
	}
	if (source == nullptr) {
		return;
	}
	GDScriptParser::DataType datatype;
	datatype.kind = GDScriptParser::DataType::VARIANT;
	source->set_datatype(datatype);
}
void GDScriptAnalyzer::mark_lambda_use_self() {
	for (GDScriptParser::LambdaNode *lambda : lambda_stack) {
		lambda->use_self = true;
	}
}
bool GDScriptAnalyzer::class_exists(const StringName &p_class) const {