Transitive generics?

[d-markey]

Consider the following classes:

  // data with a key
  abstract class Data<K> {
    K get key;
  }
  
  // link to some data
  class Link<K, T extends Data<K>> {
  
    Link({ T? value, K? key }) : _value = value, _key = key;
  
    final K? _key;
    final T? _value;
  }

The Link class has two generics K and T but K could be inferred from T.

Would it be possible to simply write:

  class Link<T extends Data<K>> {
  
    Link({ T? value, K? key }) : _value = value, _key = key;
  
    final K? _key;
    final T? _value;
  }

Currently, client classes look like:

  // some data
  class A implements Data<String> {
    A(this.key);
    final String key;
  }
  
  // some other data
  class B implements Data<int> {
    B(this.key);
    final int key;
    Link<String, A>? property;
  }

The Link<String, A>? property is essentially a Link<A>. String is redundant and is actually forced by the use of A.

[mateusfccp]

Duplicate of #620.

[d-markey]

Hi, thanks for the feedback. I'll follow up on that one then.