### 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)

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;
								break;
							
							case Variant::BASIS:
							case Variant::VECTOR2:
							case Variant::VECTOR2I:
							case Variant::VECTOR3:
							case Variant::VECTOR3I:
							case Variant::VECTOR4:
							case Variant::VECTOR4I:
							case Variant::TRANSFORM2D:
							case Variant::TRANSFORM3D:
							case Variant::PROJECTION:
								error = index_type.builtin_type != Variant::INT && index_type.builtin_type != Variant::FLOAT &&
										index_type.builtin_type != Variant::STRING && index_type.builtin_type != Variant::STRING_NAME;
								break;
							
							case Variant::COLOR:
								error = index_type.builtin_type != Variant::INT && index_type.builtin_type != Variant::STRING && index_type.builtin_type != Variant::STRING_NAME;