fix #27151, list and map literals infer using up and down info

fix #27151, list and map literals infer using up and down info

R=leafp@google.com

Committed: https://github.com/dart-lang/sdk/commit/79a9409f752dec820d4eb22bd1ea8604fac43455

[Jennifer Messerly, 2016-09-14 21:22:55]

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

[Jennifer Messerly, 2016-09-14 21:22:55]

As we discussed in the issue, this makes list/map literals consistent with other
things we infer.

We still have the problem that our heuristics should probably be revised once we
have full up+down inference.

(context: https://github.com/dart-lang/sdk/issues/27151#issuecomment-242811458)

[Jennifer Messerly, 2016-09-14 21:24:02]

BTW, I started to look at replacing matchType too, but it felt a bit cleaner to
tackle in a follow up.

[Leaf, 2016-09-14 23:10:46]

lgtm

[Leaf, 2016-09-14 23:11:35]

https://codereview.chromium.org/2343713002/diff/20001/pkg/analyzer/lib/src/ge...
File pkg/analyzer/lib/src/generated/type_system.dart (right):

https://codereview.chromium.org/2343713002/diff/20001/pkg/analyzer/lib/src/ge...
pkg/analyzer/lib/src/generated/type_system.dart:1611: return
genericType.instantiate(inferredTypes) as dynamic/*=T*/;
Does this mean that .instantiate should have a better type?  Just curious, not
suggesting that we fix it now.

[Jennifer Messerly, 2016-09-14 23:18:41]

https://codereview.chromium.org/2343713002/diff/20001/pkg/analyzer/lib/src/ge...
File pkg/analyzer/lib/src/generated/type_system.dart (right):

https://codereview.chromium.org/2343713002/diff/20001/pkg/analyzer/lib/src/ge...
pkg/analyzer/lib/src/generated/type_system.dart:1611: return
genericType.instantiate(inferredTypes) as dynamic/*=T*/;
On 2016/09/14 23:11:35, Leaf wrote:
> Does this mean that .instantiate should have a better type?  Just curious, not
> suggesting that we fix it now.

Maybe something like:

abstract class ParameterizedType<T extends ParameterizedType<T>> {
  // ...
  T instantiate(List<DartType> typeArgs);
}
abstract class InterfaceType extends ParameterizedType<InterfaceType> {
  // ...
  InterfaceType instantiate(List<DartType> typeArgs);
}
abstract class FunctionType extends ParameterizedType<FunctionType> {
  // ...
  FunctionType instantiate(List<DartType> typeArgs);
}


that's a lot of mechanism for just two cases :) so we could also just match
them:

if (genericType is FunctionType) {
  return genericType.instantiate(inferredTypes);
}
return (genericType as InterfaceType).instantiate(inferredTypes);


Or yet another option, return the list of type arguments and leave the
"instantiate" to the caller. That's more in line with how matchTypes works.
Might be cleaner?

[Jennifer Messerly, 2016-09-14 23:35:33]

Description was changed from

==========
fix #27151, list and map literals infer using up and down info
==========

to

==========
fix #27151, list and map literals infer using up and down info

R=leafp@google.com

Committed:
https://github.com/dart-lang/sdk/commit/79a9409f752dec820d4eb22bd1ea8604fac43455
==========

[Jennifer Messerly, 2016-09-14 23:35:34]

Committed patchset #2 (id:20001) manually as
79a9409f752dec820d4eb22bd1ea8604fac43455 (presubmit successful).