dart2js: Capture typedef arguments once

dart2js: Capture typedef arguments once

The type Map<T, Foo<Set<T>>> contains one type variable referenced twice,
so there are two inputs into the HTypeInfoExpression instruction.

If Foo is a typedef, T can be reused, e.g.

    typedef E Foo<E>(E a, E b);

As the typedef is expanded (to Function(Set<T>, Set<T>) => Set<T>) it
should not consume additional types from the to-level input.  We
prevent this by capturing the types and using the captured type
expressions inside the typedef expansion.

TODO: We should make the type subexpression Foo<...> be a second
HTypeInfoExpression, with Set<T> as its input (a third
HTypeInfoExpression). This would share all the Set<T> subexpressions
instead of duplicating them. This would require HTypeInfoExpression
inputs to correspond to type variables AND typedefs.

BUG= https://github.com/dart-lang/sdk/issues/28749
R=efortuna@google.com

Committed: https://github.com/dart-lang/sdk/commit/d15da7d9000381ed74520995d32168db389eaa9c

[sra1, 2017-04-13 03:06:50]

sra@google.com changed reviewers:
+ efortuna@google.com

[Emily Fortuna, 2017-04-13 18:23:30]

lgtm

https://codereview.chromium.org/2812393003/diff/20001/pkg/compiler/lib/src/js...
File pkg/compiler/lib/src/js_backend/runtime_types.dart (right):

https://codereview.chromium.org/2812393003/diff/20001/pkg/compiler/lib/src/js...
pkg/compiler/lib/src/js_backend/runtime_types.dart:1014: // First level typedef
- capture arguments for re-use within typedef body.
could you add your TODO that you describe in the CL description here, too for
future reference?

[sra1, 2017-04-13 19:35:40]

https://codereview.chromium.org/2812393003/diff/20001/pkg/compiler/lib/src/js...
File pkg/compiler/lib/src/js_backend/runtime_types.dart (right):

https://codereview.chromium.org/2812393003/diff/20001/pkg/compiler/lib/src/js...
pkg/compiler/lib/src/js_backend/runtime_types.dart:1014: // First level typedef
- capture arguments for re-use within typedef body.
On 2017/04/13 18:23:30, Emily Fortuna wrote:
> could you add your TODO that you describe in the CL description here, too for
> future reference?

Done.

[sra1, 2017-04-13 19:45:42]

Description was changed from

==========
dart2js: Capture typedef arguments once

The type Map<T, Foo<Set<T>>> contains one type variable referenced twice,
so there are two inputs into the HTypeInfoExpression instruction.

If Foo is a typedef, T can be reused, e.g.

    typedef E Foo<E>(E a, E b);

As the typedef is expanded (to Function(Set<T>, Set<T>) => Set<T>) it
should not consume additional types from the to-level input.  We
prevent this by capturing the types and using the captured type
expressions inside the typedef expansion.

TODO: We should make the type subexpression Foo<...> be a second
HTypeInfoExpression, with Set<T> as its input (a third
HTypeInfoExpression). This would share all the Set<T> subexpressions
instead of duplicating them. This would require HTypeInfoExpression
inputs to correspond to type variables AND typedefs.

BUG= https://github.com/dart-lang/sdk/issues/28749
==========

to

==========
dart2js: Capture typedef arguments once

The type Map<T, Foo<Set<T>>> contains one type variable referenced twice,
so there are two inputs into the HTypeInfoExpression instruction.

If Foo is a typedef, T can be reused, e.g.

    typedef E Foo<E>(E a, E b);

As the typedef is expanded (to Function(Set<T>, Set<T>) => Set<T>) it
should not consume additional types from the to-level input.  We
prevent this by capturing the types and using the captured type
expressions inside the typedef expansion.

TODO: We should make the type subexpression Foo<...> be a second
HTypeInfoExpression, with Set<T> as its input (a third
HTypeInfoExpression). This would share all the Set<T> subexpressions
instead of duplicating them. This would require HTypeInfoExpression
inputs to correspond to type variables AND typedefs.

BUG= https://github.com/dart-lang/sdk/issues/28749
R=efortuna@google.com

Committed:
https://github.com/dart-lang/sdk/commit/d15da7d9000381ed74520995d32168db389eaa9c
==========

[sra1, 2017-04-13 19:45:43]

Committed patchset #3 (id:40001) manually as
d15da7d9000381ed74520995d32168db389eaa9c (presubmit successful).