### Godot version

4.1.beta3

### System information

Fedora Workstation 38 - Godot 4.1.beta3 - Vulkan (Forward+)

### Issue description

**This is an issue created by the production team, we're working on it**

Currently, it's impossible to call virtual functions within GDScript.

This currently returns an error:
```gdscript
# a.gd
extends Node

func _process(delta: float) -> void:
	pass
```

```gdscript
# main.gd
extends Node

var my_node: Node = preload("res://a.gd").new()

func _process(delta: float) -> void:
	my_node._process(delta)  # Cannot call virtual function "_process()" because it hasn't been defined.
```

### Steps to reproduce

1. Create a script (`a.gd`) based on `Node` that declares `_process()`;
2. Create a main node;
3. Attach a script to the main node;
4. Initialize a variable with a new `a.gd` instance;
5. Try to run `_process()` on that node;
6. Find out that it returns an error.

### Minimal reproduction project

[virtual_functions.zip (updated)](https://github.com/godotengine/godot/files/11823992/virtual_functions.zip)


}
	if (p_cast->operand->type == GDScriptParser::Node::ARRAY && cast_type.has_container_element_type()) {
		update_array_literal_element_type(static_cast<GDScriptParser::ArrayNode *>(p_cast->operand), cast_type.get_container_element_type());
	}
	if (!cast_type.is_variant()) {
		GDScriptParser::DataType op_type = p_cast->operand->get_datatype();
		if (op_type.is_variant() || !op_type.is_hard_type()) {
			mark_node_unsafe(p_cast);
#ifdef DEBUG_ENABLED
			if (op_type.is_variant() && !op_type.is_hard_type()) {
				parser->push_warning(p_cast, GDScriptWarning::UNSAFE_CAST, cast_type.to_string());
			}
#endif
		} else {
			bool valid = false;
			if (op_type.builtin_type == Variant::INT && cast_type.kind == GDScriptParser::DataType::ENUM) {
				mark_node_unsafe(p_cast);
				valid = true;
			} else if (op_type.kind == GDScriptParser::DataType::BUILTIN && cast_type.kind == GDScriptParser::DataType::BUILTIN) {
				valid = Variant::can_convert(op_type.builtin_type, cast_type.builtin_type);
			} else if (op_type.kind != GDScriptParser::DataType::BUILTIN && cast_type.kind != GDScriptParser::DataType::BUILTIN) {
				valid = is_type_compatible(cast_type, op_type) || is_type_compatible(op_type, cast_type);
			}
			if (!valid) {
				push_error(vformat(R"(Invalid cast. Cannot convert from "%s" to "%s".)", op_type.to_string(), cast_type.to_string()), p_cast->cast_type);
			}
		}
	}
}
void GDScriptAnalyzer::reduce_dictionary(GDScriptParser::DictionaryNode *p_dictionary) {