New attribute syntax incompatible with macro_rules attr matchers

[brson]

This is a problem in compile-fail/macro-inner-attributes.rs under the new attribute syntax. In macro_rules, an attr matcher matches #[foo], which leaves no way to match inner attributes. @alexcrichton suggests changing these to meta matchers that don't match the # or brackets. Nominating.

[alexcrichton]

We decided in today's meeting to add a new meta matcher for macros, and to remove the attr matcher. I believe you should still be able to write macros that look like:

macro_rules! foo( (#[$foo:meta]) => ( fn foo() { #![$foo] } ) )

[brson]

It would be very nice to get the attribute syntax conversion done for 0.10, but this is blocking, and I don't think I will get to it this week.