restrict generic function type subtyping

restrict generic function type subtyping

R=leafp@google.com

Committed: https://github.com/dart-lang/sdk/commit/7a1b6e75b36dfae11f0e84c2b3172e905a0057dd

[Leaf, 2016-12-01 04:04:23]

leafp@google.com changed reviewers:
+ leafp@google.com

[Leaf, 2016-12-01 04:04:23]

lgtm with test:

T foo<T>(T x) {}

void takesDtoD(dynamic f(dynamic x)) {}

void test() {
  takesDtoD(foo/*INVALID_ASSIGNMENT*/)
}

class A {
  dynamic method(dynamic x) {}
}

class B extends A {
  /*INVALID_OVERRIDE*/
  T method<T>(T x) {}
}

[Jennifer Messerly, 2016-12-01 18:59:45]

On 2016/12/01 04:04:23, Leaf wrote:
> lgtm with test:
> 
> T foo<T>(T x) {}
> 
> void takesDtoD(dynamic f(dynamic x)) {}
> 
> void test() {
>   takesDtoD(foo/*INVALID_ASSIGNMENT*/)
> }
> 
> class A {
>   dynamic method(dynamic x) {}
> }
> 
> class B extends A {
>   /*INVALID_OVERRIDE*/
>   T method<T>(T x) {}
> }

thanks. I think there's test coverage, I just sent this CL to Vijay last night
without updating the test baselines :)

[Jennifer Messerly, 2016-12-02 01:15:29]

PTAL

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/lib/src/ta...
File pkg/analyzer/lib/src/task/strong/checker.dart (right):

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/lib/src/ta...
pkg/analyzer/lib/src/task/strong/checker.dart:1437: if
(!rules.isOverrideSubtypeOf(subType, baseType)) {
this fix is new

[Leaf, 2016-12-02 01:59:10]

lgtm

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/gener...
File pkg/analyzer/test/generated/type_system_test.dart (right):

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/gener...
pkg/analyzer/test/generated/type_system_test.dart:1632: void
test_genericFunction_nonGenericDoesNotSubtypeGeneric() {
This name is backwards isn't it?  Should be _genericDoesNotSubtypeNonGeneric?

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/src/t...
File pkg/analyzer/test/src/task/strong/checker_test.dart (right):

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/src/t...
pkg/analyzer/test/src/task/strong/checker_test.dart:4002: takesDtoD(/*pass
should be error:INVALID_ASSIGNMENT*/foo);
I think if you make it

dynamic foo<T>(dynamic x) => x

it might work?

[Jennifer Messerly, 2016-12-02 03:24:00]

Thanks again!

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/gener...
File pkg/analyzer/test/generated/type_system_test.dart (right):

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/gener...
pkg/analyzer/test/generated/type_system_test.dart:1632: void
test_genericFunction_nonGenericDoesNotSubtypeGeneric() {
On 2016/12/02 01:59:10, Leaf wrote:
> This name is backwards isn't it?  Should be _genericDoesNotSubtypeNonGeneric?

yes. thank you :)

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/src/t...
File pkg/analyzer/test/src/task/strong/checker_test.dart (right):

https://codereview.chromium.org/2540903003/diff/40001/pkg/analyzer/test/src/t...
pkg/analyzer/test/src/task/strong/checker_test.dart:4002: takesDtoD(/*pass
should be error:INVALID_ASSIGNMENT*/foo);
On 2016/12/02 01:59:10, Leaf wrote:
> I think if you make it
> 
> dynamic foo<T>(dynamic x) => x
> 
> it might work?

hmmm, tried it and it's still too smart to infer. Maybe after that other
inference patch when it treats no information a bit differently than `dynamic`.

[Jennifer Messerly, 2016-12-02 03:24:25]

Description was changed from

==========
restrict generic function type subtyping
==========

to

==========
restrict generic function type subtyping

R=leafp@google.com

Committed:
https://github.com/dart-lang/sdk/commit/7a1b6e75b36dfae11f0e84c2b3172e905a0057dd
==========

[Jennifer Messerly, 2016-12-02 03:24:27]

Committed patchset #4 (id:60001) manually as
7a1b6e75b36dfae11f0e84c2b3172e905a0057dd (presubmit successful).