fix #27110, mark implicit downcasts for op assign

fix #27110, mark implicit downcasts for op assign

R=leafp@google.com

Committed: https://github.com/dart-lang/sdk/commit/aea675e0ef6e43bf78321d1fc8d8e5590d4abcc7

[Jennifer Messerly, 2016-08-25 22:27:14]

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

[Jennifer Messerly, 2016-08-25 22:27:15]

Hi Leaf, pretty simple change to fix this one.

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/lib/src/task/s...
File pkg/analyzer/lib/src/task/strong/checker.dart (right):

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/lib/src/task/s...
pkg/analyzer/lib/src/task/strong/checker.dart:709:
_checkDowncast(expr.rightHandSide, paramTypes[0], from: rhsType);
this is my attempt to fix by simplification :)

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/lib/src/task/s...
pkg/analyzer/lib/src/task/strong/checker.dart:719: // TODO(jmesserly): this is
an unambiguous way to represent it, but it's
https://github.com/dart-lang/dev_compiler/issues/632 for the DDC side

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
File pkg/analyzer/test/src/task/strong/checker_test.dart (left):

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/checker_test.dart:272:
/*error:STATIC_TYPE_ERROR*/x += /*error:INVALID_ASSIGNMENT*/3.14;
this is still detected as a sideways cast by _checkDowncast but we skip emitting
it because we believe (correctly) that error_verifier already reported it.

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/checker_test.dart:304:
/*error:STATIC_TYPE_ERROR*/b -= /*error:INVALID_ASSIGNMENT*/b;
same reason here as to why this went away.

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
File pkg/analyzer/test/src/task/strong/checker_test.dart (right):

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/checker_test.dart:283:
/*info:DOWN_CAST_IMPLICIT*/x += z;
this is an example of where DDC would've been putting the cast on the wrong
side.

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/checker_test.dart:288:
/*info:DOWN_CAST_IMPLICIT*/x += /*info:DYNAMIC_CAST*/w;
here too. we need two casts. the first because "w" is dynamic, the second
because x+w is a "num" at best, so we need to check it is an "int".

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/checker_test.dart:332:
/*info:DYNAMIC_CAST*/foo += 1;
previously this line was an error, inconsistent with the line above.

[Leaf, 2016-08-25 22:35:34]

lgtm!

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/lib/src/task/s...
File pkg/analyzer/lib/src/task/strong/checker.dart (right):

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/lib/src/task/s...
pkg/analyzer/lib/src/task/strong/checker.dart:709:
_checkDowncast(expr.rightHandSide, paramTypes[0], from: rhsType);
On 2016/08/25 22:27:15, John Messerly wrote:
> this is my attempt to fix by simplification :)

:)

https://codereview.chromium.org/2271223004/diff/1/pkg/analyzer/lib/src/task/s...
pkg/analyzer/lib/src/task/strong/checker.dart:713: // If needed, mark the left
size to indicate a down cast when we assign
size -> side?

[Jennifer Messerly, 2016-08-25 22:43:11]

Description was changed from

==========
fix #27110, mark implicit downcasts for op assign
==========

to

==========
fix #27110, mark implicit downcasts for op assign

R=leafp@google.com

Committed:
https://github.com/dart-lang/sdk/commit/aea675e0ef6e43bf78321d1fc8d8e5590d4abcc7
==========

[Jennifer Messerly, 2016-08-25 22:43:12]

Committed patchset #1 (id:1) manually as
aea675e0ef6e43bf78321d1fc8d8e5590d4abcc7 (presubmit successful).