commit | 23d3e8a25f08ff0069acaf912a9d26a785dd12ae | [log] [tgz] |
---|---|---|
author | Mike Fairhurst <mfairhurst@google.com> | Wed Jun 12 23:48:48 2019 +0000 |
committer | commit-bot@chromium.org <commit-bot@chromium.org> | Wed Jun 12 23:48:48 2019 +0000 |
tree | 89263a8fe143eca4f70b3355e9932e74df8100e0 | |
parent | 52ae429a9e97e53c310ab5b08ad03043c9341de3 [diff] |
Land new subtyping algorithm; more tests but still not comprehensive. Includes changes to implicit covariance test. To redescribe this, for some tear-off C<T>.f, the member type may be contravariant if T is referenced by a parameter of C<T>.f (such as if it is of type void Function(T)). This must be a runtime failure if C<T> is a reference which has been covariantly upcast at runtime. For example, List<Object>.add, where the list is at runtime an instance of List<int>, results in a static type of void Function(Object), but a runtime type of void Function(int), which is unsound. We omit these checks, however, when it is trivially sound for all cases Previously, this was the case for tearing off `List<Null>.add`. This is no longer a valid test case for NNBD where the runtime type of that list could actually be `List<Never>`. Therefore the test has been changed to expect `List<Null>.add` to result in a cast, and a new NNBD test case has been added to test `List<Never>` cases don't get a cast. Change-Id: I61d024a249e2c2a249ad5a8037cbe3d103e3ea8b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/104361 Commit-Queue: Mike Fairhurst <mfairhurst@google.com> Reviewed-by: Paul Berry <paulberry@google.com>
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