### Godot version

v4.0.beta17.official [c40020513]

### System information

Apple M1 Max - macOS Ventura 13.1 (22C65)

### Issue description

I am getting an error due to functions no longer returning the correct typed array, when the function concatenates arrays and returns it.

In other words, the following fails:

```
func add_arrays() -> Array[ClassA]:
	var array_1: Array[ClassA] = []
	var array_2: Array[ClassA] = []
	return array_1 + array_2
```

<img width="864" alt="Screenshot 2023-02-02 at 1 02 53 PM" src="https://user-images.githubusercontent.com/905216/216320503-475bf4a1-353e-455c-87d5-69d036db706c.png">

I'm assuming when concatenating, the typing changes to a generic `Array` now? Just a guess. 

### Steps to reproduce

N/A

### Minimal reproduction project

[Godot Crash Project.zip](https://github.com/godotengine/godot/files/10568780/Godot.Crash.Project.zip)

if (current_enum) {
		for (int i = 0; i < current_enum->values.size(); i++) {
			const GDScriptParser::EnumNode::Value &element = current_enum->values[i];
			if (element.identifier->name == p_identifier->name) {
				StringName enum_name = current_enum->identifier ? current_enum->identifier->name : UNNAMED_ENUM;
				GDScriptParser::DataType type = make_enum_type(enum_name, parser->current_class->fqcn, false);
				if (element.parent_enum->identifier) {
					type.enum_type = element.parent_enum->identifier->name;
				}
				p_identifier->set_datatype(type);
				if (element.resolved) {
					p_identifier->is_constant = true;
					p_identifier->reduced_value = element.value;
				} else {
					push_error(R"(Cannot use another enum element before it was declared.)", p_identifier);
				}
				return; 
			}
		}
	}
	bool found_source = false;
	
	
	switch (p_identifier->source) {
		case GDScriptParser::IdentifierNode::FUNCTION_PARAMETER:
			p_identifier->set_datatype(p_identifier->parameter_source->get_datatype());
			found_source = true;
			break;
		case GDScriptParser::IdentifierNode::LOCAL_CONSTANT: