Record Typedef reference into Kernel FunctionType and resynthesyze typedefs in Analyzer.

Record Typedef reference into Kernel FunctionType and resynthesyze typedefs in Analyzer.

R=ahe@google.com, paulberry@google.com, sigmund@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/4ef7fd14c1de301fd08f6fe24cca07531bb924a3

[Paul Berry, 2017-08-03 20:25:46]

https://codereview.chromium.org/2986393002/diff/1/pkg/kernel/lib/ast.dart
File pkg/kernel/lib/ast.dart (right):

https://codereview.chromium.org/2986393002/diff/1/pkg/kernel/lib/ast.dart#new...
pkg/kernel/lib/ast.dart:4147: @informative
I think we should drop "@informative" here.

I realize this is a bit inconsistent with what I've said previously (that
"@informative" should be used for stuff that doesn't affect semantics), however
in this case it may be worth making an exception. 
 Consider the code:

a.dart:
  typedef void F(int i);
  F f;

b.dart:
  typedef void G(String s);
  main() {
    G g = f;
  }

When compiling b.dart, it would be nice if we could issue an error message "type
F can't be assigned to type G" instead of "type (int) -> void can't be assigned
to type (String) -> void".  To do that, we need the typedef references for both
types.  Since the type of f comes from a.dart, which might be resynthesized from
a summary, that means that we need the typedefReference to be preserved in the
summary.

So even though it's not technically semantically relevant, I think it's worth
dropping "@informative" for the benefit of good error messages.

(Note that dropping "@informative" carries a cost--it means that if someone
changes which typedef they're referencing, but the resolved type is the same,
then that will force a recompile which is technically unnecessary.  I think
that's going to be a rare enough occurrence that it's a worthwhile price to pay
for the opportunity to give better error messages)

https://codereview.chromium.org/2986393002/diff/1/pkg/kernel/lib/ast.dart#new...
pkg/kernel/lib/ast.dart:4164: @informative
Also drop "@informative" here

[scheglov, 2017-08-03 21:00:33]

PTAL

https://codereview.chromium.org/2986393002/diff/1/pkg/kernel/lib/ast.dart
File pkg/kernel/lib/ast.dart (right):

https://codereview.chromium.org/2986393002/diff/1/pkg/kernel/lib/ast.dart#new...
pkg/kernel/lib/ast.dart:4147: @informative
On 2017/08/03 20:25:45, Paul Berry wrote:
> I think we should drop "@informative" here.
> 
> I realize this is a bit inconsistent with what I've said previously (that
> "@informative" should be used for stuff that doesn't affect semantics),
however
> in this case it may be worth making an exception. 
>  Consider the code:
> 
> a.dart:
>   typedef void F(int i);
>   F f;
> 
> b.dart:
>   typedef void G(String s);
>   main() {
>     G g = f;
>   }
> 
> When compiling b.dart, it would be nice if we could issue an error message
"type
> F can't be assigned to type G" instead of "type (int) -> void can't be
assigned
> to type (String) -> void".  To do that, we need the typedef references for
both
> types.  Since the type of f comes from a.dart, which might be resynthesized
from
> a summary, that means that we need the typedefReference to be preserved in the
> summary.
> 
> So even though it's not technically semantically relevant, I think it's worth
> dropping "@informative" for the benefit of good error messages.
> 
> (Note that dropping "@informative" carries a cost--it means that if someone
> changes which typedef they're referencing, but the resolved type is the same,
> then that will force a recompile which is technically unnecessary.  I think
> that's going to be a rare enough occurrence that it's a worthwhile price to
pay
> for the opportunity to give better error messages)

Done.

https://codereview.chromium.org/2986393002/diff/1/pkg/kernel/lib/ast.dart#new...
pkg/kernel/lib/ast.dart:4164: @informative
On 2017/08/03 20:25:45, Paul Berry wrote:
> Also drop "@informative" here

Done.

[Paul Berry, 2017-08-03 21:09:16]

lgtm

[scheglov, 2017-08-04 19:01:56]

Description was changed from

==========
Record Typedef reference into Kernel FunctionType and resynthesyze typedefs in
Analyzer.

R=ahe@google.com, paulberry@google.com, sigmund@google.com
BUG=
==========

to

==========
Record Typedef reference into Kernel FunctionType and resynthesyze typedefs in
Analyzer.

R=ahe@google.com, paulberry@google.com, sigmund@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/4ef7fd14c1de301fd08f6fe24cca07531bb924a3
==========

[scheglov, 2017-08-04 19:01:58]

Committed patchset #2 (id:20001) manually as
4ef7fd14c1de301fd08f6fe24cca07531bb924a3 (presubmit successful).