### 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 (p_assignment->operation == GDScriptParser::AssignmentNode::OP_NONE && assignee_type.is_hard_type() && p_assignment->assigned_value->is_constant) {
		update_const_expression_builtin_type(p_assignment->assigned_value, assignee_type, "assign");
	}
	GDScriptParser::DataType assigned_value_type = p_assignment->assigned_value->get_datatype();
	bool assignee_is_variant = assignee_type.is_variant();
	bool assignee_is_hard = assignee_type.is_hard_type();
	bool assigned_is_variant = assigned_value_type.is_variant();
	bool assigned_is_hard = assigned_value_type.is_hard_type();
	bool compatible = true;
	bool downgrades_assignee = false;
	bool downgrades_assigned = false;
	GDScriptParser::DataType op_type = assigned_value_type;
	if (p_assignment->operation != GDScriptParser::AssignmentNode::OP_NONE && !op_type.is_variant()) {
		op_type = get_operation_type(p_assignment->variant_op, assignee_type, assigned_value_type, compatible, p_assignment->assigned_value);
		if (assignee_is_variant) {
			
			mark_node_unsafe(p_assignment);
		} else if (!compatible) {
			
			mark_node_unsafe(p_assignment);
			if (assigned_is_variant) {
				
				p_assignment->use_conversion_assign = true;
			} else {
				
				push_error(vformat(R"(Invalid operands "%s" and "%s" for assignment operator.)", assignee_type.to_string(), assigned_value_type.to_string()), p_assignment);
			}
		} else if (op_type.type_source == GDScriptParser::DataType::UNDETECTED && !assigned_is_variant) {
			
			downgrades_assignee = !assignee_is_hard;