Field initializers not run in presence of initializing constructor params

[ochafik]

class Bar {
  Bar() {
    print("Bar created");
  }
}
class Foo {
  var bar = new Bar();
  Foo([this.bar]);
}
main() {
  print(new Foo().bar);
}

Dart prints:

Bar created
null

But ddc just does not create the unused Bar instance at all.

[jmesserly]

possibly we just want to make this an error, as it doesn't seem especially useful, but not sure what others think.

[jmesserly]

related #212

[ochafik]

Clearly defining field values that aren't used is a code smell (especially if creating that value has side-effects), but I guess it's not completely unlikely to happen in the presence of multiple constructors:

class Foo {
  var bar = new Bar();
  Foo();
  Foo.withCustomBar(this.bar) { /* some different behaviour */ }
}