diff options
| -rw-r--r-- | src/libsyntax/ext/tt/macro_rules.rs | 39 | ||||
| -rw-r--r-- | src/test/compile-fail/issue-5067.rs | 62 |
2 files changed, 100 insertions, 1 deletions
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs index d222de2dd36..9f4c0b5eb80 100644 --- a/src/libsyntax/ext/tt/macro_rules.rs +++ b/src/libsyntax/ext/tt/macro_rules.rs @@ -243,7 +243,7 @@ pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension { (**tt).clone() } _ => sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs") - }).collect() + }).collect::<Vec<TokenTree>>() } _ => sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs") }; @@ -262,6 +262,11 @@ pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension { valid &= check_rhs(sess, rhs); } + // don't abort iteration early, so that errors for multiple lhses can be reported + for lhs in &lhses { + valid &= check_lhs_no_empty_seq(sess, &[lhs.clone()]) + } + let exp: Box<_> = Box::new(MacroRulesMacroExpander { name: def.ident, imported_from: def.imported_from, @@ -288,6 +293,38 @@ fn check_lhs_nt_follows(sess: &ParseSess, lhs: &TokenTree) -> bool { // after parsing/expansion. we can report every error in every macro this way. } +/// Check that the lhs contains no repetition which could match an empty token +/// tree, because then the matcher would hang indefinitely. +fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[TokenTree]) -> bool { + for tt in tts { + match *tt { + TokenTree::Token(_, _) => (), + TokenTree::Delimited(_, ref del) => if !check_lhs_no_empty_seq(sess, &del.tts) { + return false; + }, + TokenTree::Sequence(span, ref seq) => { + if seq.separator.is_none() { + if seq.tts.iter().all(|seq_tt| { + match *seq_tt { + TokenTree::Sequence(_, ref sub_seq) => + sub_seq.op == tokenstream::KleeneOp::ZeroOrMore, + _ => false, + } + }) { + sess.span_diagnostic.span_err(span, "repetition matches empty token tree"); + return false; + } + } + if !check_lhs_no_empty_seq(sess, &seq.tts) { + return false; + } + } + } + } + + true +} + fn check_rhs(sess: &ParseSess, rhs: &TokenTree) -> bool { match *rhs { TokenTree::Delimited(..) => return true, diff --git a/src/test/compile-fail/issue-5067.rs b/src/test/compile-fail/issue-5067.rs new file mode 100644 index 00000000000..b7b5553dc74 --- /dev/null +++ b/src/test/compile-fail/issue-5067.rs @@ -0,0 +1,62 @@ +// 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 <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! foo { + ( $()* ) => {}; + //~^ ERROR repetition matches empty token tree + ( $()+ ) => {}; + //~^ ERROR repetition matches empty token tree + + ( $(),* ) => {}; // PASS + ( $(),+ ) => {}; // PASS + + ( [$()*] ) => {}; + //~^ ERROR repetition matches empty token tree + ( [$()+] ) => {}; + //~^ ERROR repetition matches empty token tree + + ( [$(),*] ) => {}; // PASS + ( [$(),+] ) => {}; // PASS + + ( $($()* $(),* $(a)* $(a),* )* ) => {}; + //~^ ERROR repetition matches empty token tree + ( $($()* $(),* $(a)* $(a),* )+ ) => {}; + //~^ ERROR repetition matches empty token tree + + ( $(a $(),* $(a)* $(a),* )* ) => {}; // PASS + ( $($(a)+ $(),* $(a)* $(a),* )+ ) => {}; // PASS + + ( $(a $()+)* ) => {}; + //~^ ERROR repetition matches empty token tree + ( $(a $()*)+ ) => {}; + //~^ ERROR repetition matches empty token tree +} + + +// --- Original Issue --- // + +macro_rules! make_vec { + (a $e1:expr $($(, a $e2:expr)*)*) => ([$e1 $($(, $e2)*)*]); + //~^ ERROR repetition matches empty token tree +} + +fn main() { + let _ = make_vec!(a 1, a 2, a 3); +} + + +// --- Minified Issue --- // + +macro_rules! m { + ( $()* ) => {} + //~^ ERROR repetition matches empty token tree +} + +m!(); |