### 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)

parser->push_warning(p_assignable, GDScriptWarning::INFERENCE_ON_VARIANT, p_kind);
			}
#endif
		} else {
			if (!initializer_type.is_set()) {
				push_error(vformat(R"(Could not resolve type for %s "%s".)", p_kind, p_assignable->identifier->name), p_assignable->initializer);
			}
		}
		if (!has_specified_type) {
			type = initializer_type;
			if (!type.is_set() || (type.is_hard_type() && type.kind == GDScriptParser::DataType::BUILTIN && type.builtin_type == Variant::NIL && !is_constant)) {
				type.kind = GDScriptParser::DataType::VARIANT;
			}
			if (p_assignable->infer_datatype || is_constant) {
				type.type_source = GDScriptParser::DataType::ANNOTATED_INFERRED;
			} else {
				type.type_source = GDScriptParser::DataType::INFERRED;
			}
		} else if (!specified_type.is_variant()) {
			if (initializer_type.is_variant() || !initializer_type.is_hard_type()) {
				mark_node_unsafe(p_assignable->initializer);
				p_assignable->use_conversion_assign = true;
				if (!initializer_type.is_variant() && !is_type_compatible(specified_type, initializer_type, true, p_assignable->initializer)) {
					downgrade_node_type_source(p_assignable->initializer);
				}
			} else if (!is_type_compatible(specified_type, initializer_type, true, p_assignable->initializer)) {
				if (!is_constant && is_type_compatible(initializer_type, specified_type)) {
					mark_node_unsafe(p_assignable->initializer);
					p_assignable->use_conversion_assign = true;
				} else {