`Generate constructor` fix missing cases

[FMorschel]

A follow-up on #48359.

If we have this code:

void f(List<int> l) => l[0];

class A {}

void f() {
  var _ = A(0); // Generate constructor
  var _ = A(0, named: 0); // Generate constructor
  var a = A(named: 0); // Missing "Generate constructor"
}

I'd also like to suggest we have this same fix for:

class B extends A {
  B(super.x);
  B.named({super.named});
}

CC @srawlins

[srawlins]

Those are pretty weird. Is the fix missing in the 3rd case because of the var a (instead of var _ above) or the... lack of positional parameters? Such a strange edge bug.

[FMorschel]

Because of the missing positional parameter. The a was just an unnecessary name from my part hahaha.

Such a strange edge bug.

Agreed hahaha.