Analyzer allows non-generative constructor forwarding

[fishythefish]

class Mixin {}

class Base {
  Base();
  factory Base.f() = Base;
}

class Sub = Base with Mixin;

void main() {
  Sub.f();
}

This should be a compile-time error since the f constructor is non-generative and should not be forwarded. Analyzer fails to report an error here.