builder should return interface/abstract

[caleb-cushing0-kr]

I don't want my build() method to return the ImmutableFoo type, only Foo.

interface Foo {
  class Builder extends ImmutableFoo.Builder {
      abstract Foo build();
  }
}

ImmutableFoo foo = ImmutableBuilder.builder().build(); // compiletime error

Foo foo = ImmutableBuilder.builder().build(); // works

[elucash]

There's @Style(overshadowImplementation=true) and some other attributes to tune builders. See javadocs, most such styles documented only there.