diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs index 030cb303832af..ef2e466a04398 100644 --- a/src/libsyntax/ext/tt/macro_parser.rs +++ b/src/libsyntax/ext/tt/macro_parser.rs @@ -476,24 +476,21 @@ pub fn parse(sess: &ParseSess, } rdr.next_token(); } else /* bb_eis.len() == 1 */ { - let mut rust_parser = Parser::new(sess, cfg.clone(), Box::new(rdr.clone())); - - let mut ei = bb_eis.pop().unwrap(); - match ei.top_elts.get_tt(ei.idx) { - TokenTree::Token(span, MatchNt(_, ident)) => { + rdr.next_tok = { + let mut rust_parser = Parser::new(sess, cfg.clone(), Box::new(&mut rdr)); + let mut ei = bb_eis.pop().unwrap(); + if let TokenTree::Token(span, MatchNt(_, ident)) = ei.top_elts.get_tt(ei.idx) { let match_cur = ei.match_cur; (&mut ei.matches[match_cur]).push(Rc::new(MatchedNonterminal( parse_nt(&mut rust_parser, span, &ident.name.as_str())))); ei.idx += 1; ei.match_cur += 1; + } else { + unreachable!() } - _ => panic!() - } - cur_eis.push(ei); - - for _ in 0..rust_parser.tokens_consumed { - let _ = rdr.next_token(); - } + cur_eis.push(ei); + Some(TokenAndSpan { tok: rust_parser.token, sp: rust_parser.span }) + }; } } diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs index 939425378def6..205c709d6cb40 100644 --- a/src/libsyntax/ext/tt/transcribe.rs +++ b/src/libsyntax/ext/tt/transcribe.rs @@ -48,6 +48,7 @@ pub struct TtReader<'a> { /* cached: */ pub cur_tok: Token, pub cur_span: Span, + pub next_tok: Option, /// Transform doc comments. Only useful in macro invocations pub desugar_doc_comments: bool, pub fatal_errs: Vec>, @@ -100,6 +101,7 @@ pub fn new_tt_reader_with_doc_flag(sp_diag: &Handler, /* dummy values, never read: */ cur_tok: token::Eof, cur_span: DUMMY_SP, + next_tok: None, fatal_errs: Vec::new(), }; tt_next_token(&mut r); /* get cur_tok and cur_span set up */ @@ -178,6 +180,9 @@ fn lockstep_iter_size(t: &TokenTree, r: &TtReader) -> LockstepIterSize { /// Return the next token from the TtReader. /// EFFECT: advances the reader's token field pub fn tt_next_token(r: &mut TtReader) -> TokenAndSpan { + if let Some(tok) = r.next_tok.take() { + return tok; + } // FIXME(pcwalton): Bad copy? let ret_val = TokenAndSpan { tok: r.cur_tok.clone(), diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs index aca41bd7b5915..e62d0d925cd4f 100644 --- a/src/libsyntax/parse/lexer/mod.rs +++ b/src/libsyntax/parse/lexer/mod.rs @@ -144,7 +144,7 @@ impl<'a> Reader for StringReader<'a> { impl<'a> Reader for TtReader<'a> { fn is_eof(&self) -> bool { - self.cur_tok == token::Eof + self.peek().tok == token::Eof } fn try_next_token(&mut self) -> Result { assert!(self.fatal_errs.is_empty()); @@ -165,10 +165,31 @@ impl<'a> Reader for TtReader<'a> { self.fatal_errs.clear(); } fn peek(&self) -> TokenAndSpan { - TokenAndSpan { + self.next_tok.clone().unwrap_or(TokenAndSpan { tok: self.cur_tok.clone(), sp: self.cur_span, - } + }) + } +} + +impl<'a, 'b> Reader for &'b mut TtReader<'a> { + fn is_eof(&self) -> bool { + (**self).is_eof() + } + fn try_next_token(&mut self) -> Result { + (**self).try_next_token() + } + fn fatal(&self, m: &str) -> FatalError { + (**self).fatal(m) + } + fn err(&self, m: &str) { + (**self).err(m) + } + fn emit_fatal_errors(&mut self) { + (**self).emit_fatal_errors() + } + fn peek(&self) -> TokenAndSpan { + (**self).peek() } } diff --git a/src/test/run-pass/issue-37175.rs b/src/test/run-pass/issue-37175.rs new file mode 100644 index 0000000000000..0d3613b573e12 --- /dev/null +++ b/src/test/run-pass/issue-37175.rs @@ -0,0 +1,14 @@ +// Copyright 2016 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +macro_rules! m { (<$t:ty>) => { stringify!($t) } } +fn main() { + println!("{}", m!(>)); +}