dart_bin checked-mode: generics extension error

[DartBot]

This issue was originally filed by karl.kruk...@gmail.com

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I have a generic type Pair<P,Q> that I want to extend a generic super class.
This seems to generate a checked_mode error when the super class has one type param.

class A<E>{}
class Pair<P,Q> extends A {
  final P fst;
  final Q snd;
  Pair(this.fst,this.snd);

}
main() {
  print(new Pair<int,int>(1,2));//OK no problems

  print(new Pair<String,int>("1",2));//checked-mode type err
}

krukow:~/scratchpad$ dart_bin --enable_type_checks generic.dart
Instance of 'Pair<int, int>'
Unhandled exception:
Failed type check: type Smi is not assignable to type String of snd in /Users/krukow/scratchpad/generic.dart at line 5, column 22.
 0. Function: 'Pair.Pair.' url: '/Users/krukow/scratchpad/generic.dart' line:5 col:22
 1. Function: '::.main' url: '/Users/krukow/scratchpad/generic.dart' line:12 col:9
 

where as if it has two:
class A<E,F>{}
we get:
krukow:~/scratchpad$ dart_bin --enable_type_checks generic.dart
Instance of 'Pair<int, int>'
Instance of 'Pair<String, int>'

Using dart_bin as of Dec. 6th.

[ghost]

Set owner to @crelier.
Added Area-VM, Triaged labels.

[crelier]

Fixed in r2286.

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Added Fixed label.