No read completion suggestions when typing in assignment `..`

[scheglov]

class A {
  final other = A();
  int foo = 0;
}

void f(A a) {
  a.^.foo = 0;
}

This suggests only foo, but not other.
This means that I don't get completion help while converting a.foo into a.other.foo.

[FMorschel]

What we once talked about, @bwilkerson. The completion is looking explicitly for setters here. Maybe someone knows why that was defined (CC @keertip)? If there is no good reason for it, I agree that this condition can be removed.

[bwilkerson]

It's probably doing a simple test to see whether the selection is immediately on the left-hand side of an assignment, and isn't accounting for the fact that completing at this location would remove the cascade operator, making it be not immediately on the left-hand side of an assignment.

I wouldn't remove the restriction in general, however. I think it's useful that it only suggests setters in a context like a.f^ = 0;.

In fact, in a context like a.b^.c I would suggest that it shouldn't suggest a setter.