### 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 (!valid) {
				push_error(vformat(R"(Cannot get index "%s" from "%s".)", p_subscript->index->reduced_value, p_subscript->base->reduced_value), p_subscript->index);
				result_type.kind = GDScriptParser::DataType::VARIANT;
			} else {
				p_subscript->is_constant = true;
				p_subscript->reduced_value = value;
				result_type = type_from_variant(value, p_subscript);
			}
		} else {
			GDScriptParser::DataType base_type = p_subscript->base->get_datatype();
			GDScriptParser::DataType index_type = p_subscript->index->get_datatype();
			if (base_type.is_variant()) {
				result_type.kind = GDScriptParser::DataType::VARIANT;
				mark_node_unsafe(p_subscript);
			} else {
				if (base_type.kind == GDScriptParser::DataType::BUILTIN && !index_type.is_variant()) {
					
					bool error = index_type.kind != GDScriptParser::DataType::BUILTIN && base_type.builtin_type != Variant::DICTIONARY;
					if (!error) {
						switch (base_type.builtin_type) {
							
							case Variant::PACKED_BYTE_ARRAY:
							case Variant::PACKED_COLOR_ARRAY:
							case Variant::PACKED_FLOAT32_ARRAY:
							case Variant::PACKED_FLOAT64_ARRAY:
							case Variant::PACKED_INT32_ARRAY:
							case Variant::PACKED_INT64_ARRAY:
							case Variant::PACKED_STRING_ARRAY:
							case Variant::PACKED_VECTOR2_ARRAY:
							case Variant::PACKED_VECTOR3_ARRAY: