Implement 'instantiate to bounds' feature in resynthesizer.

Implement 'instantiate to bounds' feature in resynthesizer.

R=paulberry@google.com, brianwilkerson@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/038478ea775445a621c6b892ea2ee8d83bc79ace

[Paul Berry, 2016-05-09 21:26:36]

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/dart/e...
File pkg/analyzer/lib/src/dart/element/type.dart (right):

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/dart/e...
pkg/analyzer/lib/src/dart/element/type.dart:1155: typeArguments = null;
It seems weird to go through the setter here, since we are inside the class
implementation.  Consider doing `_typeArguments = null;` instead.

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/dart/e...
pkg/analyzer/lib/src/dart/element/type.dart:1328: _typeArguments =
typeArguments;
To facilitate garbage collection I would recommend also setting
`_typeArgumentsComputer = null;` in this method.  Note that this will only work
if you follow my suggestion above.

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/summar...
File pkg/analyzer/lib/src/summary/link.dart (right):

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/summar...
pkg/analyzer/lib/src/summary/link.dart:2249: if (linker.strongMode &&
typeParameter.bound != null) {
I don't think the logic is right here.  Consider the case of:

class C<T extends num> {}
C<int> x;

If I'm reading your code correctly, it looks like it will instantiate x with
type C<num>.

[scheglov, 2016-05-10 02:42:42]

PTAL

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/summar...
File pkg/analyzer/lib/src/summary/link.dart (right):

https://codereview.chromium.org/1963593003/diff/1/pkg/analyzer/lib/src/summar...
pkg/analyzer/lib/src/summary/link.dart:2249: if (linker.strongMode &&
typeParameter.bound != null) {
On 2016/05/09 21:26:36, Paul Berry wrote:
> I don't think the logic is right here.  Consider the case of:
> 
> class C<T extends num> {}
> C<int> x;
> 
> If I'm reading your code correctly, it looks like it will instantiate x with
> type C<num>.

Fixed.

[Paul Berry, 2016-05-10 15:55:59]

lgtm

https://codereview.chromium.org/1963593003/diff/20001/pkg/analyzer/lib/src/su...
File pkg/analyzer/lib/src/summary/link.dart (right):

https://codereview.chromium.org/1963593003/diff/20001/pkg/analyzer/lib/src/su...
pkg/analyzer/lib/src/summary/link.dart:2252: i < numTypeParameters) {
I *think* this will work, but the logic seems strange to me, because (a) the
caller guarantees that i < numTypeParameters, (b) it's not obvious that
`numTypeArguments != numTypeParameters` means "caller didn't specify this type
parameter", and (c) the logic for defaulting to dynamic in strong mode and the
logic for defaulting to dynamic in spec mode now look very different.

Consider something like this instead?

  ClassElementForLink_Class enclosingClass = element.enclosingClass;
  stack.add(enclosingClass.buildType((int i) {
    if (i < numTypeArguments) {
      // Type argument explicitly specified
      return unit._resolveTypeRef(
          ref.typeArguments[i], variable._typeParameterContext);
    } else if (linker.strongMode && typeParameter.bound != null) {
      // In strong mode, type argument defaults to bound (if any)
      return typeParameter.bound;
    } else {
      // Otherwise type argument defaults to `dynamic`
      return DynamicTypeImpl.instance;
    }
  }, const []));

[scheglov, 2016-05-10 16:58:10]

Description was changed from

==========
Implement 'instantiate to bounds' feature in resynthesizer.

R=brianwilkerson@google.com, paulberry@google.com
BUG=
==========

to

==========
Implement 'instantiate to bounds' feature in resynthesizer.

R=paulberry@google.com, brianwilkerson@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/038478ea775445a621c6b892ea2ee8d83bc79ace
==========

[scheglov, 2016-05-10 16:58:13]

Committed patchset #2 (id:20001) manually as
038478ea775445a621c6b892ea2ee8d83bc79ace (presubmit successful).