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This commit is contained in:
Julien Cretin 2019-05-29 20:21:26 +02:00
parent a96ba96915
commit 0aeab41e5a
2 changed files with 273 additions and 235 deletions
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466
src/libsyntax/ext/tt/macro_rules.rs
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@ -1,37 +1,37 @@
use crate::{ast, attr};
use crate::edition::Edition;
use crate::ext::base::{SyntaxExtension, SyntaxExtensionKind};
use crate::ext::base::{DummyResult, ExtCtxt, MacResult, TTMacroExpander};
use crate::ext::base::{SyntaxExtension, SyntaxExtensionKind};
use crate::ext::expand::{AstFragment, AstFragmentKind};
use crate::ext::hygiene::Transparency;
use crate::ext::tt::macro_parser::{Success, Error, Failure};
use crate::ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
use crate::ext::tt::macro_parser::{parse, parse_failure_msg};
use crate::ext::tt::macro_parser::{Error, Failure, Success};
use crate::ext::tt::macro_parser::{MatchedNonterminal, MatchedSeq};
use crate::ext::tt::quoted;
use crate::ext::tt::transcribe::transcribe;
use crate::feature_gate::Features;
use crate::parse::{Directory, ParseSess};
use crate::parse::parser::Parser;
use crate::parse::token::{self, Token, NtTT};
use crate::parse::token::TokenKind::*;
use crate::symbol::{Symbol, kw, sym};
use crate::parse::token::{self, NtTT, Token};
use crate::parse::{Directory, ParseSess};
use crate::symbol::{kw, sym, Symbol};
use crate::tokenstream::{DelimSpan, TokenStream, TokenTree};
use crate::{ast, attr};
use errors::FatalError;
use syntax_pos::{Span, symbol::Ident};
use log::debug;
use syntax_pos::{symbol::Ident, Span};
use rustc_data_structures::fx::{FxHashMap};
use rustc_data_structures::fx::FxHashMap;
use std::borrow::Cow;
use std::collections::hash_map::Entry;
use std::slice;
use rustc_data_structures::sync::Lrc;
use errors::Applicability;
use rustc_data_structures::sync::Lrc;
const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
`ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, \
`path`, `meta`, `tt`, `item` and `vis`";
`ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, \
`literal`, `path`, `meta`, `tt`, `item` and `vis`";
pub struct ParserAnyMacro<'a> {
parser: Parser<'a>,
@ -48,7 +48,8 @@ pub fn make(mut self: Box<ParserAnyMacro<'a>>, kind: AstFragmentKind) -> AstFrag
let ParserAnyMacro { site_span, macro_ident, ref mut parser, arm_span } = *self;
let fragment = panictry!(parser.parse_ast_fragment(kind, true).map_err(|mut e| {
if parser.token == token::Eof && e.message().ends_with(", found `<eof>`") {
if !e.span.is_dummy() { // early end of macro arm (#52866)
if !e.span.is_dummy() {
// early end of macro arm (#52866)
e.replace_span_with(parser.sess.source_map().next_point(parser.token.span));
}
let msg = &e.message[0];
@ -60,7 +61,8 @@ pub fn make(mut self: Box<ParserAnyMacro<'a>>, kind: AstFragmentKind) -> AstFrag
msg.1,
);
}
if e.span.is_dummy() { // Get around lack of span in error (#30128)
if e.span.is_dummy() {
// Get around lack of span in error (#30128)
e.replace_span_with(site_span);
if parser.sess.source_map().span_to_filename(arm_span).is_real() {
e.span_label(arm_span, "in this macro arm");
@ -99,17 +101,11 @@ fn expand<'cx>(
sp: Span,
input: TokenStream,
def_span: Option<Span>,
) -> Box<dyn MacResult+'cx> {
) -> Box<dyn MacResult + 'cx> {
if !self.valid {
return DummyResult::any(sp);
}
generic_extension(cx,
sp,
def_span,
self.name,
input,
&self.lhses,
&self.rhses)
generic_extension(cx, sp, def_span, self.name, input, &self.lhses, &self.rhses)
}
}
@ -119,14 +115,15 @@ fn trace_macros_note(cx: &mut ExtCtxt<'_>, sp: Span, message: String) {
}
/// Given `lhses` and `rhses`, this is the new macro we create
fn generic_extension<'cx>(cx: &'cx mut ExtCtxt<'_>,
sp: Span,
def_span: Option<Span>,
name: ast::Ident,
arg: TokenStream,
lhses: &[quoted::TokenTree],
rhses: &[quoted::TokenTree])
-> Box<dyn MacResult+'cx> {
fn generic_extension<'cx>(
cx: &'cx mut ExtCtxt<'_>,
sp: Span,
def_span: Option<Span>,
name: ast::Ident,
arg: TokenStream,
lhses: &[quoted::TokenTree],
rhses: &[quoted::TokenTree],
) -> Box<dyn MacResult + 'cx> {
if cx.trace_macros() {
trace_macros_note(cx, sp, format!("expanding `{}! {{ {} }}`", name, arg));
}
@ -134,10 +131,11 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt<'_>,
// Which arm's failure should we report? (the one furthest along)
let mut best_failure: Option<(Token, &str)> = None;
for (i, lhs) in lhses.iter().enumerate() { // try each arm's matchers
for (i, lhs) in lhses.iter().enumerate() {
// try each arm's matchers
let lhs_tt = match *lhs {
quoted::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
_ => cx.span_bug(sp, "malformed macro lhs")
_ => cx.span_bug(sp, "malformed macro lhs"),
};
match TokenTree::parse(cx, lhs_tt, arg.clone()) {
@ -173,8 +171,8 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt<'_>,
ownership: cx.current_expansion.directory_ownership,
};
let mut p = Parser::new(cx.parse_sess(), tts, Some(directory), true, false, None);
p.root_module_name = cx.current_expansion.module.mod_path.last()
.map(|id| id.as_str().to_string());
p.root_module_name =
cx.current_expansion.module.mod_path.last().map(|id| id.as_str().to_string());
p.process_potential_macro_variable();
// Let the context choose how to interpret the result.
@ -188,15 +186,13 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt<'_>,
site_span: sp,
macro_ident: name,
arm_span,
})
});
}
Failure(token, msg) => match best_failure {
Some((ref best_token, _)) if best_token.span.lo() >= token.span.lo() => {}
_ => best_failure = Some((token, msg))
}
Error(err_sp, ref msg) => {
cx.span_fatal(err_sp.substitute_dummy(sp), &msg[..])
}
_ => best_failure = Some((token, msg)),
},
Error(err_sp, ref msg) => cx.span_fatal(err_sp.substitute_dummy(sp), &msg[..]),
}
}
@ -212,7 +208,8 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt<'_>,
// Check whether there's a missing comma in this macro call, like `println!("{}" a);`
if let Some((arg, comma_span)) = arg.add_comma() {
for lhs in lhses { // try each arm's matchers
for lhs in lhses {
// try each arm's matchers
let lhs_tt = match *lhs {
quoted::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
_ => continue,
@ -249,7 +246,7 @@ pub fn compile(
sess: &ParseSess,
features: &Features,
def: &ast::Item,
edition: Edition
edition: Edition,
) -> SyntaxExtension {
let lhs_nm = ast::Ident::new(sym::lhs, def.span);
let rhs_nm = ast::Ident::new(sym::rhs, def.span);
@ -267,25 +264,32 @@ pub fn compile(
// ...quasiquoting this would be nice.
// These spans won't matter, anyways
let argument_gram = vec![
quoted::TokenTree::Sequence(DelimSpan::dummy(), Lrc::new(quoted::SequenceRepetition {
tts: vec![
quoted::TokenTree::MetaVarDecl(def.span, lhs_nm, tt_spec),
quoted::TokenTree::token(token::FatArrow, def.span),
quoted::TokenTree::MetaVarDecl(def.span, rhs_nm, tt_spec),
],
separator: Some(Token::new(
if body.legacy { token::Semi } else { token::Comma }, def.span
)),
op: quoted::KleeneOp::OneOrMore,
num_captures: 2,
})),
quoted::TokenTree::Sequence(
DelimSpan::dummy(),
Lrc::new(quoted::SequenceRepetition {
tts: vec![
quoted::TokenTree::MetaVarDecl(def.span, lhs_nm, tt_spec),
quoted::TokenTree::token(token::FatArrow, def.span),
quoted::TokenTree::MetaVarDecl(def.span, rhs_nm, tt_spec),
],
separator: Some(Token::new(
if body.legacy { token::Semi } else { token::Comma },
def.span,
)),
op: quoted::KleeneOp::OneOrMore,
num_captures: 2,
}),
),
// to phase into semicolon-termination instead of semicolon-separation
quoted::TokenTree::Sequence(DelimSpan::dummy(), Lrc::new(quoted::SequenceRepetition {
tts: vec![quoted::TokenTree::token(token::Semi, def.span)],
separator: None,
op: quoted::KleeneOp::ZeroOrMore,
num_captures: 0
})),
quoted::TokenTree::Sequence(
DelimSpan::dummy(),
Lrc::new(quoted::SequenceRepetition {
tts: vec![quoted::TokenTree::token(token::Semi, def.span)],
separator: None,
op: quoted::KleeneOp::ZeroOrMore,
num_captures: 0,
}),
),
];
let argument_map = match parse(sess, body.stream(), &argument_gram, None, true) {
@ -307,8 +311,9 @@ pub fn compile(
// Extract the arguments:
let lhses = match *argument_map[&lhs_nm] {
MatchedSeq(ref s, _) => {
s.iter().map(|m| {
MatchedSeq(ref s, _) => s
.iter()
.map(|m| {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
let tt = quoted::parse(
@ -327,14 +332,15 @@ pub fn compile(
}
}
sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
}).collect::<Vec<quoted::TokenTree>>()
}
_ => sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
})
.collect::<Vec<quoted::TokenTree>>(),
_ => sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs"),
};
let rhses = match *argument_map[&rhs_nm] {
MatchedSeq(ref s, _) => {
s.iter().map(|m| {
MatchedSeq(ref s, _) => s
.iter()
.map(|m| {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
return quoted::parse(
@ -345,14 +351,15 @@ pub fn compile(
&def.attrs,
edition,
def.id,
).pop()
.unwrap();
)
.pop()
.unwrap();
}
}
sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
}).collect::<Vec<quoted::TokenTree>>()
}
_ => sess.span_diagnostic.span_bug(def.span, "wrong-structured rhs")
})
.collect::<Vec<quoted::TokenTree>>(),
_ => sess.span_diagnostic.span_bug(def.span, "wrong-structured rhs"),
};
for rhs in &rhses {
@ -366,16 +373,12 @@ pub fn compile(
sess,
slice::from_ref(lhs),
&mut FxHashMap::default(),
def.id
def.id,
);
}
let expander: Box<_> = Box::new(MacroRulesMacroExpander {
name: def.ident,
lhses,
rhses,
valid,
});
let expander: Box<_> =
Box::new(MacroRulesMacroExpander { name: def.ident, lhses, rhses, valid });
let default_transparency = if attr::contains_name(&def.attrs, sym::rustc_transparent_macro) {
Transparency::Transparent
@ -385,29 +388,34 @@ pub fn compile(
Transparency::Opaque
};
let allow_internal_unstable = attr::find_by_name(&def.attrs, sym::allow_internal_unstable)
.map(|attr| attr
.meta_item_list()
.map(|list| list.iter()
.filter_map(|it| {
let name = it.ident().map(|ident| ident.name);
if name.is_none() {
sess.span_diagnostic.span_err(it.span(),
"allow internal unstable expects feature names")
}
name
let allow_internal_unstable =
attr::find_by_name(&def.attrs, sym::allow_internal_unstable).map(|attr| {
attr.meta_item_list()
.map(|list| {
list.iter()
.filter_map(|it| {
let name = it.ident().map(|ident| ident.name);
if name.is_none() {
sess.span_diagnostic.span_err(
it.span(),
"allow internal unstable expects feature names",
)
}
name
})
.collect::<Vec<Symbol>>()
.into()
})
.collect::<Vec<Symbol>>().into()
)
.unwrap_or_else(|| {
sess.span_diagnostic.span_warn(
attr.span, "allow_internal_unstable expects list of feature names. In the \
future this will become a hard error. Please use `allow_internal_unstable(\
foo, bar)` to only allow the `foo` and `bar` features",
);
vec![sym::allow_internal_unstable_backcompat_hack].into()
})
);
.unwrap_or_else(|| {
sess.span_diagnostic.span_warn(
attr.span,
"allow_internal_unstable expects list of feature names. In the \
future this will become a hard error. Please use `allow_internal_unstable(\
foo, bar)` to only allow the `foo` and `bar` features",
);
vec![sym::allow_internal_unstable_backcompat_hack].into()
})
});
let allow_internal_unsafe = attr::contains_name(&def.attrs, sym::allow_internal_unsafe);
@ -418,14 +426,14 @@ pub fn compile(
}
}
let unstable_feature = attr::find_stability(&sess,
&def.attrs, def.span).and_then(|stability| {
if let attr::StabilityLevel::Unstable { issue, .. } = stability.level {
Some((stability.feature, issue))
} else {
None
}
});
let unstable_feature =
attr::find_stability(&sess, &def.attrs, def.span).and_then(|stability| {
if let attr::StabilityLevel::Unstable { issue, .. } = stability.level {
Some((stability.feature, issue))
} else {
None
}
});
SyntaxExtension {
kind: SyntaxExtensionKind::LegacyBang(expander),
@ -440,10 +448,12 @@ pub fn compile(
}
}
fn check_lhs_nt_follows(sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
lhs: &quoted::TokenTree) -> bool {
fn check_lhs_nt_follows(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
lhs: &quoted::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.
if let quoted::TokenTree::Delimited(_, ref tts) = *lhs {
@ -464,19 +474,22 @@ fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
for tt in tts {
match *tt {
TokenTree::Token(..) | TokenTree::MetaVar(..) | TokenTree::MetaVarDecl(..) => (),
TokenTree::Delimited(_, ref del) => if !check_lhs_no_empty_seq(sess, &del.tts) {
return false;
},
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() && seq.tts.iter().all(|seq_tt| {
match *seq_tt {
if seq.separator.is_none()
&& seq.tts.iter().all(|seq_tt| match *seq_tt {
TokenTree::MetaVarDecl(_, _, id) => id.name == sym::vis,
TokenTree::Sequence(_, ref sub_seq) =>
TokenTree::Sequence(_, ref sub_seq) => {
sub_seq.op == quoted::KleeneOp::ZeroOrMore
|| sub_seq.op == quoted::KleeneOp::ZeroOrOne,
|| sub_seq.op == quoted::KleeneOp::ZeroOrOne
}
_ => false,
}
}) {
})
{
let sp = span.entire();
sess.span_diagnostic.span_err(sp, "repetition matches empty token tree");
return false;
@ -517,7 +530,7 @@ fn check_lhs_duplicate_matcher_bindings(
if !check_lhs_duplicate_matcher_bindings(sess, &del.tts, metavar_names, node_id) {
return false;
}
},
}
TokenTree::Sequence(_, ref seq) => {
if !check_lhs_duplicate_matcher_bindings(sess, &seq.tts, metavar_names, node_id) {
return false;
@ -533,15 +546,17 @@ fn check_lhs_duplicate_matcher_bindings(
fn check_rhs(sess: &ParseSess, rhs: &quoted::TokenTree) -> bool {
match *rhs {
quoted::TokenTree::Delimited(..) => return true,
_ => sess.span_diagnostic.span_err(rhs.span(), "macro rhs must be delimited")
_ => sess.span_diagnostic.span_err(rhs.span(), "macro rhs must be delimited"),
}
false
}
fn check_matcher(sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
matcher: &[quoted::TokenTree]) -> bool {
fn check_matcher(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
matcher: &[quoted::TokenTree],
) -> bool {
let first_sets = FirstSets::new(matcher);
let empty_suffix = TokenSet::empty();
let err = sess.span_diagnostic.err_count();
@ -620,8 +635,8 @@ fn build_recur(sets: &mut FirstSets, tts: &[TokenTree]) -> TokenSet {
// Reverse scan: Sequence comes before `first`.
if subfirst.maybe_empty
|| seq_rep.op == quoted::KleeneOp::ZeroOrMore
|| seq_rep.op == quoted::KleeneOp::ZeroOrOne
|| seq_rep.op == quoted::KleeneOp::ZeroOrMore
|| seq_rep.op == quoted::KleeneOp::ZeroOrOne
{
// If sequence is potentially empty, then
// union them (preserving first emptiness).
@ -659,7 +674,6 @@ fn first(&self, tts: &[quoted::TokenTree]) -> TokenSet {
TokenTree::Sequence(sp, ref seq_rep) => {
match self.first.get(&sp.entire()) {
Some(&Some(ref subfirst)) => {
// If the sequence contents can be empty, then the first
// token could be the separator token itself.
@ -670,8 +684,8 @@ fn first(&self, tts: &[quoted::TokenTree]) -> TokenSet {
assert!(first.maybe_empty);
first.add_all(subfirst);
if subfirst.maybe_empty
|| seq_rep.op == quoted::KleeneOp::ZeroOrMore
|| seq_rep.op == quoted::KleeneOp::ZeroOrOne
|| seq_rep.op == quoted::KleeneOp::ZeroOrMore
|| seq_rep.op == quoted::KleeneOp::ZeroOrOne
{
// continue scanning for more first
// tokens, but also make sure we
@ -720,7 +734,9 @@ struct TokenSet {
impl TokenSet {
// Returns a set for the empty sequence.
fn empty() -> Self { TokenSet { tokens: Vec::new(), maybe_empty: true } }
fn empty() -> Self {
TokenSet { tokens: Vec::new(), maybe_empty: true }
}
// Returns the set `{ tok }` for the single-token (and thus
// non-empty) sequence [tok].
@ -789,12 +805,14 @@ fn add_all(&mut self, other: &Self) {
//
// Requires that `first_sets` is pre-computed for `matcher`;
// see `FirstSets::new`.
fn check_matcher_core(sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
first_sets: &FirstSets,
matcher: &[quoted::TokenTree],
follow: &TokenSet) -> TokenSet {
fn check_matcher_core(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
first_sets: &FirstSets,
matcher: &[quoted::TokenTree],
follow: &TokenSet,
) -> TokenSet {
use quoted::TokenTree;
let mut last = TokenSet::empty();
@ -804,11 +822,13 @@ fn check_matcher_core(sess: &ParseSess,
// then ensure T can also be followed by any element of FOLLOW.
'each_token: for i in 0..matcher.len() {
let token = &matcher[i];
let suffix = &matcher[i+1..];
let suffix = &matcher[i + 1..];
let build_suffix_first = || {
let mut s = first_sets.first(suffix);
if s.maybe_empty { s.add_all(follow); }
if s.maybe_empty {
s.add_all(follow);
}
s
};
@ -824,7 +844,8 @@ fn check_matcher_core(sess: &ParseSess,
let can_be_followed_by_any;
if let Err(bad_frag) = has_legal_fragment_specifier(sess, features, attrs, token) {
let msg = format!("invalid fragment specifier `{}`", bad_frag);
sess.span_diagnostic.struct_span_err(token.span(), &msg)
sess.span_diagnostic
.struct_span_err(token.span(), &msg)
.help(VALID_FRAGMENT_NAMES_MSG)
.emit();
// (This eliminates false positives and duplicates
@ -879,12 +900,8 @@ fn check_matcher_core(sess: &ParseSess,
// At this point, `suffix_first` is built, and
// `my_suffix` is some TokenSet that we can use
// for checking the interior of `seq_rep`.
let next = check_matcher_core(sess,
features,
attrs,
first_sets,
&seq_rep.tts,
my_suffix);
let next =
check_matcher_core(sess, features, attrs, first_sets, &seq_rep.tts, my_suffix);
if next.maybe_empty {
last.add_all(&next);
} else {
@ -906,16 +923,17 @@ fn check_matcher_core(sess: &ParseSess,
for next_token in &suffix_first.tokens {
match is_in_follow(next_token, &frag_spec.as_str()) {
IsInFollow::Invalid(msg, help) => {
sess.span_diagnostic.struct_span_err(next_token.span(), &msg)
.help(help).emit();
sess.span_diagnostic
.struct_span_err(next_token.span(), &msg)
.help(help)
.emit();
// don't bother reporting every source of
// conflict for a particular element of `last`.
continue 'each_last;
}
IsInFollow::Yes => {}
IsInFollow::No(possible) => {
let may_be = if last.tokens.len() == 1 &&
suffix_first.tokens.len() == 1
let may_be = if last.tokens.len() == 1 && suffix_first.tokens.len() == 1
{
"is"
} else {
@ -925,12 +943,14 @@ fn check_matcher_core(sess: &ParseSess,
let sp = next_token.span();
let mut err = sess.span_diagnostic.struct_span_err(
sp,
&format!("`${name}:{frag}` {may_be} followed by `{next}`, which \
is not allowed for `{frag}` fragments",
name=name,
frag=frag_spec,
next=quoted_tt_to_string(next_token),
may_be=may_be),
&format!(
"`${name}:{frag}` {may_be} followed by `{next}`, which \
is not allowed for `{frag}` fragments",
name = name,
frag = frag_spec,
next = quoted_tt_to_string(next_token),
may_be = may_be
),
);
err.span_label(
sp,
@ -942,16 +962,18 @@ fn check_matcher_core(sess: &ParseSess,
&[t] => {
err.note(&format!(
"only {} is allowed after `{}` fragments",
t,
frag_spec,
t, frag_spec,
));
}
ts => {
err.note(&format!(
"{}{} or {}",
msg,
ts[..ts.len() - 1].iter().map(|s| *s)
.collect::<Vec<_>>().join(", "),
ts[..ts.len() - 1]
.iter()
.map(|s| *s)
.collect::<Vec<_>>()
.join(", "),
ts[ts.len() - 1],
));
}
@ -1026,13 +1048,13 @@ fn is_in_follow(tok: &quoted::TokenTree, frag: &str) -> IsInFollow {
// since items *must* be followed by either a `;` or a `}`, we can
// accept anything after them
IsInFollow::Yes
},
}
"block" => {
// anything can follow block, the braces provide an easy boundary to
// maintain
IsInFollow::Yes
},
"stmt" | "expr" => {
}
"stmt" | "expr" => {
const TOKENS: &[&str] = &["`=>`", "`,`", "`;`"];
match tok {
TokenTree::Token(token) => match token.kind {
@ -1041,7 +1063,7 @@ fn is_in_follow(tok: &quoted::TokenTree, frag: &str) -> IsInFollow {
},
_ => IsInFollow::No(TOKENS),
}
},
}
"pat" => {
const TOKENS: &[&str] = &["`=>`", "`,`", "`=`", "`|`", "`if`", "`in`"];
match tok {
@ -1052,40 +1074,48 @@ fn is_in_follow(tok: &quoted::TokenTree, frag: &str) -> IsInFollow {
},
_ => IsInFollow::No(TOKENS),
}
},
}
"path" | "ty" => {
const TOKENS: &[&str] = &[
"`{`", "`[`", "`=>`", "`,`", "`>`","`=`", "`:`", "`;`", "`|`", "`as`",
"`{`", "`[`", "`=>`", "`,`", "`>`", "`=`", "`:`", "`;`", "`|`", "`as`",
"`where`",
];
match tok {
TokenTree::Token(token) => match token.kind {
OpenDelim(token::DelimToken::Brace) |
OpenDelim(token::DelimToken::Bracket) |
Comma | FatArrow | Colon | Eq | Gt | BinOp(token::Shr) | Semi |
BinOp(token::Or) => IsInFollow::Yes,
Ident(name, false) if name == kw::As ||
name == kw::Where => IsInFollow::Yes,
OpenDelim(token::DelimToken::Brace)
| OpenDelim(token::DelimToken::Bracket)
| Comma
| FatArrow
| Colon
| Eq
| Gt
| BinOp(token::Shr)
| Semi
| BinOp(token::Or) => IsInFollow::Yes,
Ident(name, false) if name == kw::As || name == kw::Where => {
IsInFollow::Yes
}
_ => IsInFollow::No(TOKENS),
},
TokenTree::MetaVarDecl(_, _, frag) if frag.name == sym::block =>
IsInFollow::Yes,
TokenTree::MetaVarDecl(_, _, frag) if frag.name == sym::block => {
IsInFollow::Yes
}
_ => IsInFollow::No(TOKENS),
}
},
}
"ident" | "lifetime" => {
// being a single token, idents and lifetimes are harmless
IsInFollow::Yes
},
}
"literal" => {
// literals may be of a single token, or two tokens (negative numbers)
IsInFollow::Yes
},
}
"meta" | "tt" => {
// being either a single token or a delimited sequence, tt is
// harmless
IsInFollow::Yes
},
}
"vis" => {
// Explicitly disallow `priv`, on the off chance it comes back.
const TOKENS: &[&str] = &["`,`", "an ident", "a type"];
@ -1093,30 +1123,39 @@ fn is_in_follow(tok: &quoted::TokenTree, frag: &str) -> IsInFollow {
TokenTree::Token(token) => match token.kind {
Comma => IsInFollow::Yes,
Ident(name, is_raw) if is_raw || name != kw::Priv => IsInFollow::Yes,
_ => if token.can_begin_type() {
IsInFollow::Yes
} else {
IsInFollow::No(TOKENS)
_ => {
if token.can_begin_type() {
IsInFollow::Yes
} else {
IsInFollow::No(TOKENS)
}
}
},
TokenTree::MetaVarDecl(_, _, frag) if frag.name == sym::ident
|| frag.name == sym::ty
|| frag.name == sym::path =>
IsInFollow::Yes,
TokenTree::MetaVarDecl(_, _, frag)
if frag.name == sym::ident
|| frag.name == sym::ty
|| frag.name == sym::path =>
{
IsInFollow::Yes
}
_ => IsInFollow::No(TOKENS),
}
},
}
"" => IsInFollow::Yes, // kw::Invalid
_ => IsInFollow::Invalid(format!("invalid fragment specifier `{}`", frag),
VALID_FRAGMENT_NAMES_MSG),
_ => IsInFollow::Invalid(
format!("invalid fragment specifier `{}`", frag),
VALID_FRAGMENT_NAMES_MSG,
),
}
}
}
fn has_legal_fragment_specifier(sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
tok: &quoted::TokenTree) -> Result<(), String> {
fn has_legal_fragment_specifier(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
tok: &quoted::TokenTree,
) -> Result<(), String> {
debug!("has_legal_fragment_specifier({:?})", tok);
if let quoted::TokenTree::MetaVarDecl(_, _, ref frag_spec) = *tok {
let frag_span = tok.span();
@ -1127,11 +1166,13 @@ fn has_legal_fragment_specifier(sess: &ParseSess,
Ok(())
}
fn is_legal_fragment_specifier(_sess: &ParseSess,
_features: &Features,
_attrs: &[ast::Attribute],
frag_name: Symbol,
_frag_span: Span) -> bool {
fn is_legal_fragment_specifier(
_sess: &ParseSess,
_features: &Features,
_attrs: &[ast::Attribute],
frag_name: Symbol,
_frag_span: Span,
) -> bool {
/*
* If new fragment specifiers are invented in nightly, `_sess`,
* `_features`, `_attrs`, and `_frag_span` will be useful here
@ -1139,9 +1180,20 @@ fn is_legal_fragment_specifier(_sess: &ParseSess,
* this function.
*/
match frag_name {
sym::item | sym::block | sym::stmt | sym::expr | sym::pat |
sym::lifetime | sym::path | sym::ty | sym::ident | sym::meta | sym::tt |
sym::vis | sym::literal | kw::Invalid => true,
sym::item
| sym::block
| sym::stmt
| sym::expr
| sym::pat
| sym::lifetime
| sym::path
| sym::ty
| sym::ident
| sym::meta
| sym::tt
| sym::vis
| sym::literal
| kw::Invalid => true,
_ => false,
}
}
@ -1151,7 +1203,9 @@ fn quoted_tt_to_string(tt: &quoted::TokenTree) -> String {
quoted::TokenTree::Token(ref token) => crate::print::pprust::token_to_string(&token),
quoted::TokenTree::MetaVar(_, name) => format!("${}", name),
quoted::TokenTree::MetaVarDecl(_, name, kind) => format!("${}:{}", name, kind),
_ => panic!("unexpected quoted::TokenTree::{{Sequence or Delimited}} \
in follow set checker"),
_ => panic!(
"unexpected quoted::TokenTree::{{Sequence or Delimited}} \
in follow set checker"
),
}
}

42
src/libsyntax/ext/tt/quoted.rs
View File

@ -1,12 +1,12 @@
use crate::ast;
use crate::ast::NodeId;
use crate::ext::tt::macro_parser;
use crate::feature_gate::Features;
use crate::parse::token::{self, Token, TokenKind};
use crate::parse::ParseSess;
use crate::print::pprust;
use crate::tokenstream::{self, DelimSpan};
use crate::ast;
use crate::symbol::kw;
use crate::tokenstream::{self, DelimSpan};
use syntax_pos::{edition::Edition, BytePos, Span};
@ -137,8 +137,7 @@ pub fn span(&self) -> Span {
TokenTree::Token(Token { span, .. })
| TokenTree::MetaVar(span, _)
| TokenTree::MetaVarDecl(span, _, _) => span,
TokenTree::Delimited(span, _)
| TokenTree::Sequence(span, _) => span.entire(),
TokenTree::Delimited(span, _) | TokenTree::Sequence(span, _) => span.entire(),
}
}
@ -199,7 +198,7 @@ pub fn parse(
match tree {
TokenTree::MetaVar(start_sp, ident) if expect_matchers => {
let span = match trees.next() {
Some(tokenstream::TokenTree::Token(Token { kind: token::Colon, span })) =>
Some(tokenstream::TokenTree::Token(Token { kind: token::Colon, span })) => {
match trees.next() {
Some(tokenstream::TokenTree::Token(token)) => match token.ident() {
Some((kind, _)) => {
@ -209,22 +208,13 @@ pub fn parse(
}
_ => token.span,
},
tree => tree
.as_ref()
.map(tokenstream::TokenTree::span)
.unwrap_or(span),
},
tree => tree
.as_ref()
.map(tokenstream::TokenTree::span)
.unwrap_or(start_sp),
tree => tree.as_ref().map(tokenstream::TokenTree::span).unwrap_or(span),
}
}
tree => tree.as_ref().map(tokenstream::TokenTree::span).unwrap_or(start_sp),
};
sess.missing_fragment_specifiers.borrow_mut().insert(span);
result.push(TokenTree::MetaVarDecl(
span,
ident,
ast::Ident::invalid(),
));
result.push(TokenTree::MetaVarDecl(span, ident, ast::Ident::invalid()));
}
// Not a metavar or no matchers allowed, so just return the tree
@ -311,10 +301,8 @@ fn parse_tree(
// `tree` is followed by a random token. This is an error.
Some(tokenstream::TokenTree::Token(token)) => {
let msg = format!(
"expected identifier, found `{}`",
pprust::token_to_string(&token),
);
let msg =
format!("expected identifier, found `{}`", pprust::token_to_string(&token),);
sess.span_diagnostic.span_err(token.span, &msg);
TokenTree::MetaVar(token.span, ast::Ident::invalid())
}
@ -371,10 +359,7 @@ fn parse_kleene_op(
Some(op) => Ok(Ok((op, token.span))),
None => Ok(Err(token)),
},
tree => Err(tree
.as_ref()
.map(tokenstream::TokenTree::span)
.unwrap_or(span)),
tree => Err(tree.as_ref().map(tokenstream::TokenTree::span).unwrap_or(span)),
}
}
@ -426,8 +411,7 @@ fn parse_sep_and_kleene_op(
};
// If we ever get to this point, we have experienced an "unexpected token" error
sess.span_diagnostic
.span_err(span, "expected one of: `*`, `+`, or `?`");
sess.span_diagnostic.span_err(span, "expected one of: `*`, `+`, or `?`");
// Return a dummy
(None, KleeneOp::ZeroOrMore)