Fix the most egregious instances of "local ambiguity: multiple parsing options..." error in macros, which often occurs when trying to match parts of Rust syntax.
For example, this matcher: `fn $name:ident( $($param:ident : $pty:ty),* )` would fail when parsing `fn foo()`, because macro parser wouldn't realize that an ident cannot start with `)`. This resolves #5902, and at least partially mitigates #9364 and #3232.
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@ -350,7 +350,16 @@ pub fn parse(sess: &ParseSess,
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sp_lo: sp.lo
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});
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}
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MatchNonterminal(_,_,_) => { bb_eis.push(ei) }
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MatchNonterminal(_,_,_) => {
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// Built-in nonterminals never start with these tokens,
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// so we can eliminate them from consideration.
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match tok {
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token::RPAREN |
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token::RBRACE |
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token::RBRACKET => {},
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_ => bb_eis.push(ei)
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}
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}
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MatchTok(ref t) => {
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let mut ei_t = ei.clone();
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if token_name_eq(t,&tok) {
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@ -0,0 +1,30 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![feature(macro_rules)]
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macro_rules! list (
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( ($($id:ident),*) ) => (());
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( [$($id:ident),*] ) => (());
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( {$($id:ident),*} ) => (());
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)
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macro_rules! tt_list (
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( ($($tt:tt),*) ) => (());
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)
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pub fn main() {
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list!( () );
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list!( [] );
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list!( {} );
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tt_list!( (a, b, c) );
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tt_list!( () );
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}
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