Add a test of the runtime type of a tearoff that uses a covariant generic parameter.

Add a test of the runtime type of a tearoff that uses a covariant generic parameter.

This case has caused some confusion so I thought it would be nice to
have an explicit test case for it.

R=leafp@google.com

Committed: https://github.com/dart-lang/sdk/commit/804bcabcc12f24da64c32cf28d5531b1d2cf1712

[Paul Berry, 2017-08-28 16:05:57]

paulberry@google.com changed reviewers:
+ jmesserly@google.com, leafp@google.com

[Leaf, 2017-08-28 23:10:55]

lgtm

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
File tests/language_2/covariant_tear_off_type_test.dart (right):

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
tests/language_2/covariant_tear_off_type_test.dart:5: // Regression test for
dart2js that used to be confused when inlining
Cut and paste remnant?

[Jennifer Messerly, 2017-08-28 23:50:56]

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
File tests/language_2/covariant_tear_off_type_test.dart (right):

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
tests/language_2/covariant_tear_off_type_test.dart:5: // Regression test for
dart2js that used to be confused when inlining
this comment looks obsolete

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
tests/language_2/covariant_tear_off_type_test.dart:24: // `(Object) -> int`. 
(Not, for example, `(List<Object>) -> int` or
is it possible to add any of these expectations? It would be great to
distinguish Dart 1 from Dart2, so non-strong mode does not pass the test.
Unfortunately, kinda hard since Dart 1 allows function parameter types to go
either way.

Could also do something like:

tearoff.runtimeType.toString().startsWith('(Object)');

[Jennifer Messerly, 2017-08-28 23:54:16]

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
File tests/language_2/covariant_tear_off_type_test.dart (right):

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
tests/language_2/covariant_tear_off_type_test.dart:26: Expect.isTrue(tearoff is
F<Object, int>);
Here's another test we can add to tell Dart 1 and Dart 2 apart:

  // Because the function accepts any object, we can pass strings to it.
  // This will not work in Dart 1.
  Expect.isTrue(tearoff is F<String, int>);

[Paul Berry, 2017-08-29 17:24:49]

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
File tests/language_2/covariant_tear_off_type_test.dart (right):

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
tests/language_2/covariant_tear_off_type_test.dart:5: // Regression test for
dart2js that used to be confused when inlining
On 2017/08/28 23:10:55, Leaf wrote:
> Cut and paste remnant?

Fixed, thanks.

https://codereview.chromium.org/3012443003/diff/1/tests/language_2/covariant_...
tests/language_2/covariant_tear_off_type_test.dart:26: Expect.isTrue(tearoff is
F<Object, int>);
On 2017/08/28 23:54:16, Jennifer Messerly wrote:
> Here's another test we can add to tell Dart 1 and Dart 2 apart:
> 
>   // Because the function accepts any object, we can pass strings to it.
>   // This will not work in Dart 1.
>   Expect.isTrue(tearoff is F<String, int>);

I like this suggestion.  Done.

[Paul Berry, 2017-08-29 17:50:46]

Description was changed from

==========
Add a test of the runtime type of a tearoff that uses a covariant generic
parameter.

This case has caused some confusion so I thought it would be nice to
have an explicit test case for it.
==========

to

==========
Add a test of the runtime type of a tearoff that uses a covariant generic
parameter.

This case has caused some confusion so I thought it would be nice to
have an explicit test case for it.

R=leafp@google.com

Committed:
https://github.com/dart-lang/sdk/commit/804bcabcc12f24da64c32cf28d5531b1d2cf1712
==========

[Paul Berry, 2017-08-29 17:50:47]

Committed patchset #2 (id:20001) manually as
804bcabcc12f24da64c32cf28d5531b1d2cf1712 (presubmit successful).