Godot: GDScript: no error when there is a trailing comma in function arguments

[ThakeeNathees]

Godot version: v4.0.dev.custom_build 35ff38b3d

OS/device including version: windows 10

Issue description:

func f(p, ): ## <-- no errors
    print(p)

func _ready():
    f(0, ) ## <-- no error

[Xrayez]

When running with the GDScript test runner for this snippet, generates this output file:

Parser bug: invalid inheritance.

EDIT: seems to happen for all "valid" scripts though...

[Calinou]

This may be done by design. Trailing commas in function declarations and calls make it possible to write more diff-friendly code:

# If we add one more argument, we have to modify only 1 line (1 addition).
hello(
    "foo",
    "bar",
    "baz",
)

# If we add one more argument, we have to modify 2 lines (2 additions, 1 deletion).
hello(
    "foo",
    "bar",
    "baz"
)

Many languages such as Python and JavaScript now allow this. Therefore, I would prefer this behavior to stay in :slightly_smiling_face:

[vnen]

Yes, this is intended. Many users asked for this so I added it.

[Xrayez]

I guess the problem comes from having this inline over multiple lines, but if that's difficult to solve then perhaps not worth it.