Powershell: Given that methods in custom classes do not support optional parameters (with default values), attempting to define them should fail

[mklement0]

Note: If #9701 is implemented, this issue becomes moot.

Steps to reproduce

class Foo {
  # This method definition shouldn't be permitted, because optional parameters
  # aren't supported.
  [string] Bar($Baz = 'Bam') { return $Baz }
}
[Foo]::new().Bar()

Expected behavior

The class definition should fail, given that optional parameters aren't supported.

Actual behavior

The class definition succeeds, but the argument-less invocation of the method fails.

Cannot find an overload for "Bar" and the argument count: "0".

Environment data

PowerShell Core 6.2.1

[iSazonov]

If we implement this error message it will 75% from implementing the feature :-)

[vexx32]

Yeah, in truth if we're going to be poking around here I'd rather we make this work properly.

[mklement0]

I didn't realize that was on the menu.

I'll have the feature then, please :)

[iSazonov]

Maybe reopen with the feature request?

[mklement0]

Good idea; please see #9701

[iSazonov]

@mklement0 Thanks! I think we can close the issue.