### 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)

GDScriptParser::DataType parent_return_type;
		List<GDScriptParser::DataType> parameters_types;
		int default_par_count = 0;
		BitField<MethodFlags> method_flags;
		StringName native_base;
		if (!p_is_lambda && get_function_signature(p_function, false, base_type, function_name, parent_return_type, parameters_types, default_par_count, method_flags, &native_base)) {
			bool valid = p_function->is_static == method_flags.has_flag(METHOD_FLAG_STATIC);
			valid = valid && parent_return_type == p_function->get_datatype();
			int par_count_diff = p_function->parameters.size() - parameters_types.size();
			valid = valid && par_count_diff >= 0;
			valid = valid && default_value_count >= default_par_count + par_count_diff;
			int i = 0;
			for (const GDScriptParser::DataType &par_type : parameters_types) {
				valid = valid && par_type == p_function->parameters[i++]->get_datatype();
			}
			if (!valid) {
				
				String parent_signature = String(function_name) + "(";
				int j = 0;
				for (const GDScriptParser::DataType &par_type : parameters_types) {
					if (j > 0) {
						parent_signature += ", ";
					}
					String parameter = par_type.to_string();
					if (parameter == "null") {
						parameter = "Variant";
					}
					parent_signature += parameter;
					if (j >= parameters_types.size() - default_par_count) {
						parent_signature += " = <default>";