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Jan 22, 2015
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107 changes: 54 additions & 53 deletions src/libsyntax/ext/tt/macro_rules.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,8 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use ast::{TokenTree, TtDelimited, TtSequence, TtToken};
use ast;
use ast::{self, TokenTree, TtDelimited, TtSequence, TtToken};
use codemap::{Span, DUMMY_SP};
use ext::base::{ExtCtxt, MacResult, SyntaxExtension};
use ext::base::{NormalTT, TTMacroExpander};
Expand All @@ -19,9 +18,8 @@ use ext::tt::macro_parser::{parse, parse_or_else};
use parse::lexer::{new_tt_reader, new_tt_reader_with_doc_flag};
use parse::parser::Parser;
use parse::attr::ParserAttr;
use parse::token::{special_idents, gensym_ident, NtTT, Token};
use parse::token::{self, special_idents, gensym_ident, NtTT, Token};
use parse::token::Token::*;
use parse::token;
use print;
use ptr::P;

Expand Down Expand Up @@ -333,16 +331,20 @@ fn check_matcher<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token)

let tok = if let TtToken(_, ref tok) = *token { tok } else { unreachable!() };
// If T' is in the set FOLLOW(NT), continue. Else, reject.
match &next_token {
&Eof => return Some((sp, tok.clone())),
_ if is_in_follow(cx, &next_token, frag_spec.as_str()) => continue,
next => {
match (&next_token, is_in_follow(cx, &next_token, frag_spec.as_str())) {
(&Eof, _) => return Some((sp, tok.clone())),
(_, Ok(true)) => continue,
(next, Ok(false)) => {
cx.span_err(sp, format!("`${0}:{1}` is followed by `{2}`, which \
is not allowed for `{1}` fragments",
name.as_str(), frag_spec.as_str(),
token_to_string(next)).as_slice());
continue
},
(_, Err(msg)) => {
cx.span_err(sp, msg.as_slice());
continue
}
}
},
TtSequence(sp, ref seq) => {
Expand Down Expand Up @@ -409,51 +411,50 @@ fn check_matcher<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token)
last
}

fn is_in_follow(cx: &ExtCtxt, tok: &Token, frag: &str) -> bool {
fn is_in_follow(_: &ExtCtxt, tok: &Token, frag: &str) -> Result<bool, String> {
if let &CloseDelim(_) = tok {
return true;
}

match frag {
"item" => {
// since items *must* be followed by either a `;` or a `}`, we can
// accept anything after them
true
},
"block" => {
// anything can follow block, the braces provide a easy boundary to
// maintain
true
},
"stmt" | "expr" => {
match *tok {
FatArrow | Comma | Semi => true,
_ => false
}
},
"pat" => {
match *tok {
FatArrow | Comma | Eq => true,
_ => false
}
},
"path" | "ty" => {
match *tok {
Comma | FatArrow | Colon | Eq | Gt => true,
Ident(i, _) if i.as_str() == "as" => true,
_ => false
}
},
"ident" => {
// being a single token, idents are harmless
true
},
"meta" | "tt" => {
// being either a single token or a delimited sequence, tt is
// harmless
true
},
_ => cx.bug(format!("unrecognized builtin nonterminal {}",
frag).as_slice()),
Ok(true)
} else {
match frag {
"item" => {
// since items *must* be followed by either a `;` or a `}`, we can
// accept anything after them
Ok(true)
},
"block" => {
// anything can follow block, the braces provide a easy boundary to
// maintain
Ok(true)
},
"stmt" | "expr" => {
match *tok {
FatArrow | Comma | Semi => Ok(true),
_ => Ok(false)
}
},
"pat" => {
match *tok {
FatArrow | Comma | Eq => Ok(true),
_ => Ok(false)
}
},
"path" | "ty" => {
match *tok {
Comma | FatArrow | Colon | Eq | Gt => Ok(true),
Ident(i, _) if i.as_str() == "as" => Ok(true),
_ => Ok(false)
}
},
"ident" => {
// being a single token, idents are harmless
Ok(true)
},
"meta" | "tt" => {
// being either a single token or a delimited sequence, tt is
// harmless
Ok(true)
},
_ => Err(format!("unrecognized builtin nonterminal `{}`", frag))
}
}
}
14 changes: 14 additions & 0 deletions src/test/compile-fail/issue-21356.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

macro_rules! test { ($wrong:t_ty ..) => () }
//~^ ERROR: unrecognized builtin nonterminal `t_ty`

fn main() {}