Revive throw as an expression but not for rethrow.

Revive throw as an expression but not for rethrow.

[kasperl, 2012-12-10 14:50:05]

LGTM. Do you have a negative test that ensures that we cannot have rethrow in an
expression context? Make sure to include nasty stuff like:

   throw; * 42;

to make sure that it doesn't parse as a rethrow as an expression.

https://codereview.chromium.org/11497009/diff/1/sdk/lib/_internal/compiler/im...
File sdk/lib/_internal/compiler/implementation/scanner/parser.dart (right):

https://codereview.chromium.org/11497009/diff/1/sdk/lib/_internal/compiler/im...
sdk/lib/_internal/compiler/implementation/scanner/parser.dart:1896: if
(identical(afterIdKind, EQ_TOKEN) || identical(afterIdKind, SEMICOLON_TOKEN) ||
Long line.

https://codereview.chromium.org/11497009/diff/1/sdk/lib/_internal/compiler/im...
sdk/lib/_internal/compiler/implementation/scanner/parser.dart:1978:
listener.endRethrow(throwToken, token);
Add a comment that it's important that you aren't consuming the ; token?

[kasperl, 2012-12-10 15:01:22]

We just chatted more about this. It seems pretty broken.

The scary stuff is code like this:

   2 * throw;

We have to be much more careful.

[ngeoffray, 2012-12-11 09:32:19]

Thanks for taking a look. I'm closing this CL for now until the spec gets
updated.