Incorrect type display of function arguments in GDScript editor tooltips

[Xwdit]

Godot version

4.0.alpha12

System information

Windows11, Nvidia RTX 2060, Vulkan

Issue description

For function arguments without a defined type but with a default value set, the arguments type will be displayed as the type of the default value in the editor tooltip (should be Variant)

Steps to reproduce

Just look at the tooltip when calling the fn function:

func _ready():
	fn()


func fn(x = [1, 2, 3], y:int = 1):
	return

Minimal reproduction project

func _ready():
	fn()


func fn(x = [1, 2, 3], y:int = 1):
	return