### 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)

#ifdef DEBUG_ENABLED
		if (p_function->parameters[i]->usages == 0 && !String(p_function->parameters[i]->identifier->name).begins_with("_")) {
			String visible_name = function_name;
			if (function_name == StringName()) {
				visible_name = p_is_lambda ? "<anonymous lambda>" : "<unknown function>";
			}
			parser->push_warning(p_function->parameters[i]->identifier, GDScriptWarning::UNUSED_PARAMETER, visible_name, p_function->parameters[i]->identifier->name);
		}
		is_shadowing(p_function->parameters[i]->identifier, "function parameter");
#endif 
#ifdef TOOLS_ENABLED
		if (p_function->parameters[i]->initializer) {
			default_value_count++;
			if (p_function->parameters[i]->initializer->is_constant) {
				p_function->default_arg_values.push_back(p_function->parameters[i]->initializer->reduced_value);
			} else {
				p_function->default_arg_values.push_back(Variant()); 
			}
		}
#endif 
	}
	if (!p_is_lambda && function_name == GDScriptLanguage::get_singleton()->strings._init) {
		
		GDScriptParser::DataType return_type = parser->current_class->get_datatype();
		return_type.is_meta_type = false;
		p_function->set_datatype(return_type);
		if (p_function->return_type) {
			GDScriptParser::DataType declared_return = resolve_datatype(p_function->return_type);
			if (declared_return.kind != GDScriptParser::DataType::BUILTIN || declared_return.builtin_type != Variant::NIL) {
				push_error("Constructor cannot have an explicit return type.", p_function->return_type);