Add a hint on static uses of fuzzy arrows.

Add a hint on static uses of fuzzy arrows.

This causes the analyzer to emit a hint message when fuzzy arrow
subtyping is used.

BUG=
R=brianwilkerson@google.com

Committed: https://github.com/dart-lang/sdk/commit/1f7c0d2c4c511956cacb72d528372c7cabb2ac1e

[Leaf, 2017-08-30 21:55:00]

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

[Brian Wilkerson, 2017-08-30 22:04:02]

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

[Brian Wilkerson, 2017-08-30 22:04:03]

This also needs to increment the value of the field AnalysisDriver.DATA_VERSION
(in pkg/analyzer/lib/src/dart/analysis/driver.dart). Other than that, lgtm.

[Leaf, 2017-08-30 22:19:47]

On 2017/08/30 22:04:03, Brian Wilkerson wrote:
> This also needs to increment the value of the field
AnalysisDriver.DATA_VERSION
> (in pkg/analyzer/lib/src/dart/analysis/driver.dart). Other than that, lgtm.

Done, thanks!

[Leaf, 2017-08-30 22:27:33]

Description was changed from

==========
Add a hint on static uses of fuzzy arrows.

This causes the analyzer to emit a hint message when fuzzy arrow
subtyping is used.

BUG=
==========

to

==========
Add a hint on static uses of fuzzy arrows.

This causes the analyzer to emit a hint message when fuzzy arrow
subtyping is used.

BUG=
R=brianwilkerson@google.com

Committed:
https://github.com/dart-lang/sdk/commit/1f7c0d2c4c511956cacb72d528372c7cabb2ac1e
==========

[Leaf, 2017-08-30 22:27:34]

Committed patchset #3 (id:40001) manually as
1f7c0d2c4c511956cacb72d528372c7cabb2ac1e (presubmit successful).

[Jennifer Messerly, 2017-08-30 23:29:48]

oh nice! I've got a suggestion on how to simplify so we don't need any changes
in type_system.dart

https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
File pkg/analyzer/lib/src/task/strong/checker.dart (right):

https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
pkg/analyzer/lib/src/task/strong/checker.dart:1081: from ??=
_getDefiniteType(expr);
this is not needed because `_checkImplicitCast` did this before this function
was called

Also the `expr` parameter is not necessary.

https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
pkg/analyzer/lib/src/task/strong/checker.dart:1085: if (rules.isSubtypeOf(from,
to)) {
alternate way to implement this method that may be simpler:

// If it is a subtype with fuzzy arrows on,
/ check to see if it still is with them off.
if (rules.isSubtypeOf(from, to)) {
  // Remove fuzzy arrows
  var cFrom = rules.typeToConcreteType(from);
  var cTo = rules.typeToConcreteType(to);
  // If still true, no warning needed
  if (rules.isSubtypeOf(cFrom, cTo)) return;
  _recordMessage(expr, HintCode.USES_DYNAMIC_AS_BOTTOM, [from, to]);
}

[Leaf, 2017-08-30 23:40:18]

On 2017/08/30 23:29:48, Jennifer Messerly wrote:
> oh nice! I've got a suggestion on how to simplify so we don't need any changes
> in type_system.dart
> 
>
https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
> File pkg/analyzer/lib/src/task/strong/checker.dart (right):
> 
>
https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
> pkg/analyzer/lib/src/task/strong/checker.dart:1081: from ??=
> _getDefiniteType(expr);
> this is not needed because `_checkImplicitCast` did this before this function
> was called
> 
> Also the `expr` parameter is not necessary.
> 
>
https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
> pkg/analyzer/lib/src/task/strong/checker.dart:1085: if
(rules.isSubtypeOf(from,
> to)) {
> alternate way to implement this method that may be simpler:
> 
> // If it is a subtype with fuzzy arrows on,
> / check to see if it still is with them off.
> if (rules.isSubtypeOf(from, to)) {
>   // Remove fuzzy arrows
>   var cFrom = rules.typeToConcreteType(from);
>   var cTo = rules.typeToConcreteType(to);
>   // If still true, no warning needed
>   if (rules.isSubtypeOf(cFrom, cTo)) return;
>   _recordMessage(expr, HintCode.USES_DYNAMIC_AS_BOTTOM, [from, to]);
> }

Good suggestions, thanks.  I'll follow up with another CL.

[karlklose, 2017-08-31 06:29:16]

On 2017/08/30 23:40:18, Leaf wrote:
> On 2017/08/30 23:29:48, Jennifer Messerly wrote:
> > oh nice! I've got a suggestion on how to simplify so we don't need any
changes
> > in type_system.dart
> > 
> >
>
https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
> > File pkg/analyzer/lib/src/task/strong/checker.dart (right):
> > 
> >
>
https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
> > pkg/analyzer/lib/src/task/strong/checker.dart:1081: from ??=
> > _getDefiniteType(expr);
> > this is not needed because `_checkImplicitCast` did this before this
function
> > was called
> > 
> > Also the `expr` parameter is not necessary.
> > 
> >
>
https://codereview.chromium.org/3012593002/diff/40001/pkg/analyzer/lib/src/ta...
> > pkg/analyzer/lib/src/task/strong/checker.dart:1085: if
> (rules.isSubtypeOf(from,
> > to)) {
> > alternate way to implement this method that may be simpler:
> > 
> > // If it is a subtype with fuzzy arrows on,
> > / check to see if it still is with them off.
> > if (rules.isSubtypeOf(from, to)) {
> >   // Remove fuzzy arrows
> >   var cFrom = rules.typeToConcreteType(from);
> >   var cTo = rules.typeToConcreteType(to);
> >   // If still true, no warning needed
> >   if (rules.isSubtypeOf(cFrom, cTo)) return;
> >   _recordMessage(expr, HintCode.USES_DYNAMIC_AS_BOTTOM, [from, to]);
> > }
> 
> Good suggestions, thanks.  I'll follow up with another CL.

This change added a lot of warnings to pkg/kernel, pkg/analysis_server,
pkg/compiler, and pkg/front_end, which broke
pkg/front_end/test/fasta/analyze_test.

Run python tools/test.py -m release --checked
pkg/front_end/test/fasta/analyze_test on this CL to reproduce.