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Auto merge of #33713 - LeoTestard:macro-rules-invalid-lhs, r=pnkfelix

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Make sure that macros that didn't pass LHS checking are not expanded.

This avoid duplicate errors for things like invalid fragment specifiers, or
parsing errors for ambiguous macros.
This commit is contained in:
bors 2016-05-25 09:40:06 -07:00
commit da66f2fd8c
5 changed files with 96 additions and 46 deletions
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11
src/libsyntax/ext/tt/macro_parser.rs
View File

@ -549,13 +549,8 @@ pub fn parse_nt<'a>(p: &mut Parser<'a>, sp: Span, name: &str) -> Nonterminal {
token::NtPath(Box::new(panictry!(p.parse_path(PathStyle::Type))))
},
"meta" => token::NtMeta(panictry!(p.parse_meta_item())),
_ => {
p.span_fatal_help(sp,
&format!("invalid fragment specifier `{}`", name),
"valid fragment specifiers are `ident`, `block`, \
`stmt`, `expr`, `pat`, `ty`, `path`, `meta`, `tt` \
and `item`").emit();
panic!(FatalError);
}
// this is not supposed to happen, since it has been checked
// when compiling the macro.
_ => p.span_bug(sp, "invalid fragment specifier")
}
}

93
src/libsyntax/ext/tt/macro_rules.rs
View File

@ -291,17 +291,16 @@ pub fn compile<'cx>(cx: &'cx mut ExtCtxt,
let lhses = match **argument_map.get(&lhs_nm.name).unwrap() {
MatchedSeq(ref s, _) => {
s.iter().map(|m| match **m {
MatchedNonterminal(NtTT(ref tt)) => (**tt).clone(),
MatchedNonterminal(NtTT(ref tt)) => {
valid &= check_lhs_nt_follows(cx, tt);
(**tt).clone()
}
_ => cx.span_bug(def.span, "wrong-structured lhs")
}).collect()
}
_ => cx.span_bug(def.span, "wrong-structured lhs")
};
for lhs in &lhses {
check_lhs_nt_follows(cx, lhs, def.span);
}
let rhses = match **argument_map.get(&rhs_nm.name).unwrap() {
MatchedSeq(ref s, _) => {
s.iter().map(|m| match **m {
@ -330,19 +329,19 @@ pub fn compile<'cx>(cx: &'cx mut ExtCtxt,
// why is this here? because of https://github.com/rust-lang/rust/issues/27774
fn ref_slice<A>(s: &A) -> &[A] { use std::slice::from_raw_parts; unsafe { from_raw_parts(s, 1) } }
fn check_lhs_nt_follows(cx: &mut ExtCtxt, lhs: &TokenTree, sp: Span) {
fn check_lhs_nt_follows(cx: &mut ExtCtxt, lhs: &TokenTree) -> bool {
// lhs is going to be like TokenTree::Delimited(...), where the
// entire lhs is those tts. Or, it can be a "bare sequence", not wrapped in parens.
match lhs {
&TokenTree::Delimited(_, ref tts) => {
check_matcher(cx, &tts.tts);
},
tt @ &TokenTree::Sequence(..) => {
check_matcher(cx, ref_slice(tt));
},
_ => cx.span_err(sp, "invalid macro matcher; matchers must be contained \
in balanced delimiters or a repetition indicator")
};
&TokenTree::Delimited(_, ref tts) => check_matcher(cx, &tts.tts),
tt @ &TokenTree::Sequence(..) => check_matcher(cx, ref_slice(tt)),
_ => {
cx.span_err(lhs.get_span(),
"invalid macro matcher; matchers must be contained \
in balanced delimiters or a repetition indicator");
false
}
}
// we don't abort on errors on rejection, the driver will do that for us
// after parsing/expansion. we can report every error in every macro this way.
}
@ -364,20 +363,25 @@ struct OnFail {
action: OnFailAction,
}
#[derive(Copy, Clone, Debug)]
#[derive(Copy, Clone, Debug, PartialEq)]
enum OnFailAction { Warn, Error, DoNothing }
impl OnFail {
fn warn() -> OnFail { OnFail { saw_failure: false, action: OnFailAction::Warn } }
fn error() -> OnFail { OnFail { saw_failure: false, action: OnFailAction::Error } }
fn do_nothing() -> OnFail { OnFail { saw_failure: false, action: OnFailAction::DoNothing } }
fn react(&mut self, cx: &mut ExtCtxt, sp: Span, msg: &str) {
fn react(&mut self, cx: &mut ExtCtxt, sp: Span, msg: &str, help: Option<&str>) {
match self.action {
OnFailAction::DoNothing => {}
OnFailAction::Error => cx.span_err(sp, msg),
OnFailAction::Error => {
let mut err = cx.struct_span_err(sp, msg);
if let Some(msg) = help { err.span_help(sp, msg); }
err.emit();
}
OnFailAction::Warn => {
cx.struct_span_warn(sp, msg)
.span_note(sp, "The above warning will be a hard error in the next release.")
let mut warn = cx.struct_span_warn(sp, msg);
if let Some(msg) = help { warn.span_help(sp, msg); }
warn.span_note(sp, "The above warning will be a hard error in the next release.")
.emit();
}
};
@ -385,7 +389,7 @@ impl OnFail {
}
}
fn check_matcher(cx: &mut ExtCtxt, matcher: &[TokenTree]) {
fn check_matcher(cx: &mut ExtCtxt, matcher: &[TokenTree]) -> bool {
// Issue 30450: when we are through a warning cycle, we can just
// error on all failure conditions (and remove check_matcher_old).
@ -400,6 +404,9 @@ fn check_matcher(cx: &mut ExtCtxt, matcher: &[TokenTree]) {
OnFail::warn()
};
check_matcher_new(cx, matcher, &mut on_fail);
// matcher is valid if the new pass didn't see any error,
// or if errors were considered warnings
on_fail.action != OnFailAction::Error || !on_fail.saw_failure
}
// returns the last token that was checked, for TokenTree::Sequence.
@ -435,11 +442,11 @@ fn check_matcher_old<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token, on_fai
// sequence, which may itself be a sequence,
// and so on).
on_fail.react(cx, sp,
&format!("`${0}:{1}` is followed by a \
sequence repetition, which is not \
allowed for `{1}` fragments",
name, frag_spec)
);
&format!("`${0}:{1}` is followed by a \
sequence repetition, which is not \
allowed for `{1}` fragments",
name, frag_spec),
None);
Eof
},
// die next iteration
@ -456,8 +463,10 @@ fn check_matcher_old<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token, on_fai
// If T' is in the set FOLLOW(NT), continue. Else, reject.
match (&next_token, is_in_follow(cx, &next_token, &frag_spec.name.as_str())) {
(_, Err(msg)) => {
on_fail.react(cx, sp, &msg);
(_, Err((msg, _))) => {
// no need for help message, those messages
// are never emitted anyway...
on_fail.react(cx, sp, &msg, None);
continue
}
(&Eof, _) => return Some((sp, tok.clone())),
@ -466,7 +475,7 @@ fn check_matcher_old<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token, on_fai
on_fail.react(cx, sp, &format!("`${0}:{1}` is followed by `{2}`, which \
is not allowed for `{1}` fragments",
name, frag_spec,
token_to_string(next)));
token_to_string(next)), None);
continue
},
}
@ -494,7 +503,8 @@ fn check_matcher_old<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token, on_fai
delim.close_token(),
Some(_) => {
on_fail.react(cx, sp, "sequence repetition followed by \
another sequence repetition, which is not allowed");
another sequence repetition, which is not allowed",
None);
Eof
},
None => Eof
@ -514,7 +524,7 @@ fn check_matcher_old<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token, on_fai
Some(&&TokenTree::Delimited(_, ref delim)) => delim.close_token(),
Some(_) => {
on_fail.react(cx, sp, "sequence repetition followed by another \
sequence repetition, which is not allowed");
sequence repetition, which is not allowed", None);
Eof
},
None => Eof
@ -810,7 +820,11 @@ fn check_matcher_core(cx: &mut ExtCtxt,
TokenTree::Token(sp, ref tok) => {
let can_be_followed_by_any;
if let Err(bad_frag) = has_legal_fragment_specifier(tok) {
on_fail.react(cx, sp, &format!("invalid fragment specifier `{}`", bad_frag));
on_fail.react(cx, sp,
&format!("invalid fragment specifier `{}`", bad_frag),
Some("valid fragment specifiers are `ident`, `block`, \
`stmt`, `expr`, `pat`, `ty`, `path`, `meta`, `tt` \
and `item`"));
// (This eliminates false positives and duplicates
// from error messages.)
can_be_followed_by_any = true;
@ -884,8 +898,8 @@ fn check_matcher_core(cx: &mut ExtCtxt,
if let MatchNt(ref name, ref frag_spec) = *t {
for &(sp, ref next_token) in &suffix_first.tokens {
match is_in_follow(cx, next_token, &frag_spec.name.as_str()) {
Err(msg) => {
on_fail.react(cx, sp, &msg);
Err((msg, help)) => {
on_fail.react(cx, sp, &msg, Some(help));
// don't bother reporting every source of
// conflict for a particular element of `last`.
continue 'each_last;
@ -907,7 +921,9 @@ fn check_matcher_core(cx: &mut ExtCtxt,
name=name,
frag=frag_spec,
next=token_to_string(next_token),
may_be=may_be));
may_be=may_be),
None
);
}
}
}
@ -978,7 +994,7 @@ fn can_be_followed_by_any(frag: &str) -> bool {
/// break macros that were relying on that binary operator as a
/// separator.
// when changing this do not forget to update doc/book/macros.md!
fn is_in_follow(_: &ExtCtxt, tok: &Token, frag: &str) -> Result<bool, String> {
fn is_in_follow(_: &ExtCtxt, tok: &Token, frag: &str) -> Result<bool, (String, &'static str)> {
if let &CloseDelim(_) = tok {
// closing a token tree can never be matched by any fragment;
// iow, we always require that `(` and `)` match, etc.
@ -1027,7 +1043,10 @@ fn is_in_follow(_: &ExtCtxt, tok: &Token, frag: &str) -> Result<bool, String> {
// harmless
Ok(true)
},
_ => Err(format!("invalid fragment specifier `{}`", frag))
_ => Err((format!("invalid fragment specifier `{}`", frag),
"valid fragment specifiers are `ident`, `block`, \
`stmt`, `expr`, `pat`, `ty`, `path`, `meta`, `tt` \
and `item`"))
}
}
}

2
src/test/compile-fail/invalid-macro-matcher.rs
View File

@ -9,7 +9,7 @@
// except according to those terms.
macro_rules! invalid {
_ => (); //~^ ERROR invalid macro matcher
_ => (); //~ ERROR invalid macro matcher
}
fn main() {

19
src/test/compile-fail/macro-invalid-fragment-spec.rs Normal file
View File

@ -0,0 +1,19 @@
// 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(
($x:foo) => ()
//~^ ERROR invalid fragment specifier
//~| HELP valid fragment specifiers are
);
fn main() {
foo!(foo);
}

17
src/test/compile-fail/macro-missing-delimiters.rs Normal file
View File

@ -0,0 +1,17 @@
// 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! baz(
baz => () //~ ERROR invalid macro matcher;
);
fn main() {
baz!(baz);
}