diff --git a/src/libsyntax/feature_gate/check.rs b/src/libsyntax/feature_gate/check.rs index d9cc5f6c169b6..74a92669a4d61 100644 --- a/src/libsyntax/feature_gate/check.rs +++ b/src/libsyntax/feature_gate/check.rs @@ -862,18 +862,17 @@ pub fn check_crate(krate: &ast::Crate, maybe_stage_features(&parse_sess.span_diagnostic, krate, unstable); let mut visitor = PostExpansionVisitor { parse_sess, features }; + let spans = parse_sess.gated_spans.spans.borrow(); macro_rules! gate_all { - ($gate:ident, $msg:literal) => { gate_all!($gate, $gate, $msg); }; - ($spans:ident, $gate:ident, $msg:literal) => { - for span in &*parse_sess.gated_spans.$spans.borrow() { + ($gate:ident, $msg:literal) => { + for span in spans.get(&sym::$gate).unwrap_or(&vec![]) { gate_feature!(&visitor, $gate, *span, $msg); } } } - gate_all!(let_chains, "`let` expressions in this position are experimental"); gate_all!(async_closure, "async closures are unstable"); - gate_all!(yields, generators, "yield syntax is experimental"); + gate_all!(generators, "yield syntax is experimental"); gate_all!(or_patterns, "or-patterns syntax is experimental"); gate_all!(const_extern_fn, "`const extern fn` definitions are unstable"); @@ -884,7 +883,7 @@ pub fn check_crate(krate: &ast::Crate, // FIXME(eddyb) do something more useful than always // disabling these uses of early feature-gatings. if false { - for span in &*parse_sess.gated_spans.$gate.borrow() { + for span in spans.get(&sym::$gate).unwrap_or(&vec![]) { gate_feature!(&visitor, $gate, *span, $msg); } } @@ -901,7 +900,6 @@ pub fn check_crate(krate: &ast::Crate, gate_all!(try_blocks, "`try` blocks are unstable"); gate_all!(label_break_value, "labels on blocks are unstable"); gate_all!(box_syntax, "box expression syntax is experimental; you can call `Box::new` instead"); - // To avoid noise about type ascription in common syntax errors, // only emit if it is the *only* error. (Also check it last.) if parse_sess.span_diagnostic.err_count() == 0 { diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 7652c730e51b6..efd716e7c4aa6 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1121,7 +1121,7 @@ impl<'a> Parser<'a> { self.expected_tokens.push(TokenType::Keyword(kw::Crate)); if self.is_crate_vis() { self.bump(); // `crate` - self.sess.gated_spans.crate_visibility_modifier.borrow_mut().push(self.prev_span); + self.sess.gated_spans.gate(sym::crate_visibility_modifier, self.prev_span); return Ok(respan(self.prev_span, VisibilityKind::Crate(CrateSugar::JustCrate))); } diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs index 97b1092452aaf..79be67528b904 100644 --- a/src/libsyntax/parse/parser/expr.rs +++ b/src/libsyntax/parse/parser/expr.rs @@ -16,10 +16,10 @@ use crate::parse::token::{self, Token, TokenKind}; use crate::print::pprust; use crate::ptr::P; use crate::source_map::{self, Span}; -use crate::symbol::{kw, sym}; use crate::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par}; use errors::Applicability; +use syntax_pos::symbol::{kw, sym}; use syntax_pos::Symbol; use std::mem; use rustc_data_structures::thin_vec::ThinVec; @@ -252,7 +252,7 @@ impl<'a> Parser<'a> { self.last_type_ascription = Some((self.prev_span, maybe_path)); lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Type)?; - self.sess.gated_spans.type_ascription.borrow_mut().push(lhs.span); + self.sess.gated_spans.gate(sym::type_ascription, lhs.span); continue } else if op == AssocOp::DotDot || op == AssocOp::DotDotEq { // If we didn’t have to handle `x..`/`x..=`, it would be pretty easy to @@ -455,7 +455,7 @@ impl<'a> Parser<'a> { let e = self.parse_prefix_expr(None); let (span, e) = self.interpolated_or_expr_span(e)?; let span = lo.to(span); - self.sess.gated_spans.box_syntax.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::box_syntax, span); (span, ExprKind::Box(e)) } token::Ident(..) if self.token.is_ident_named(sym::not) => { @@ -1045,7 +1045,7 @@ impl<'a> Parser<'a> { } let span = lo.to(hi); - self.sess.gated_spans.yields.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::generators, span); } else if self.eat_keyword(kw::Let) { return self.parse_let_expr(attrs); } else if is_span_rust_2018 && self.eat_keyword(kw::Await) { @@ -1264,7 +1264,7 @@ impl<'a> Parser<'a> { outer_attrs: ThinVec, ) -> PResult<'a, P> { if let Some(label) = opt_label { - self.sess.gated_spans.label_break_value.borrow_mut().push(label.ident.span); + self.sess.gated_spans.gate(sym::label_break_value, label.ident.span); } self.expect(&token::OpenDelim(token::Brace))?; @@ -1293,7 +1293,7 @@ impl<'a> Parser<'a> { }; if asyncness.is_async() { // Feature-gate `async ||` closures. - self.sess.gated_spans.async_closure.borrow_mut().push(self.prev_span); + self.sess.gated_spans.gate(sym::async_closure, self.prev_span); } let capture_clause = self.parse_capture_clause(); @@ -1415,8 +1415,7 @@ impl<'a> Parser<'a> { if let ExprKind::Let(..) = cond.kind { // Remove the last feature gating of a `let` expression since it's stable. - let last = self.sess.gated_spans.let_chains.borrow_mut().pop(); - debug_assert_eq!(cond.span, last.unwrap()); + self.sess.gated_spans.ungate_last(sym::let_chains, cond.span); } Ok(cond) @@ -1433,7 +1432,7 @@ impl<'a> Parser<'a> { |this| this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into()) )?; let span = lo.to(expr.span); - self.sess.gated_spans.let_chains.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::let_chains, span); Ok(self.mk_expr(span, ExprKind::Let(pat, expr), attrs)) } @@ -1654,7 +1653,7 @@ impl<'a> Parser<'a> { Err(error) } else { let span = span_lo.to(body.span); - self.sess.gated_spans.try_blocks.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::try_blocks, span); Ok(self.mk_expr(span, ExprKind::TryBlock(body), attrs)) } } diff --git a/src/libsyntax/parse/parser/generics.rs b/src/libsyntax/parse/parser/generics.rs index 51caae69c86a4..3c094750b4d98 100644 --- a/src/libsyntax/parse/parser/generics.rs +++ b/src/libsyntax/parse/parser/generics.rs @@ -3,7 +3,8 @@ use super::{Parser, PResult}; use crate::ast::{self, WhereClause, GenericParam, GenericParamKind, GenericBounds, Attribute}; use crate::parse::token; use crate::source_map::DUMMY_SP; -use crate::symbol::kw; + +use syntax_pos::symbol::{kw, sym}; impl<'a> Parser<'a> { /// Parses bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`. @@ -62,7 +63,7 @@ impl<'a> Parser<'a> { self.expect(&token::Colon)?; let ty = self.parse_ty()?; - self.sess.gated_spans.const_generics.borrow_mut().push(lo.to(self.prev_span)); + self.sess.gated_spans.gate(sym::const_generics, lo.to(self.prev_span)); Ok(GenericParam { ident, diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs index 5b60e7e6dba05..51e96b55c726c 100644 --- a/src/libsyntax/parse/parser/item.rs +++ b/src/libsyntax/parse/parser/item.rs @@ -147,9 +147,7 @@ impl<'a> Parser<'a> { let unsafety = self.parse_unsafety(); if self.check_keyword(kw::Extern) { - self.sess.gated_spans.const_extern_fn.borrow_mut().push( - lo.to(self.token.span) - ); + self.sess.gated_spans.gate(sym::const_extern_fn, lo.to(self.token.span)); } let abi = self.parse_extern_abi()?; self.bump(); // `fn` @@ -830,7 +828,7 @@ impl<'a> Parser<'a> { .emit(); } - self.sess.gated_spans.trait_alias.borrow_mut().push(whole_span); + self.sess.gated_spans.gate(sym::trait_alias, whole_span); Ok((ident, ItemKind::TraitAlias(tps, bounds), None)) } else { @@ -1712,7 +1710,7 @@ impl<'a> Parser<'a> { let span = lo.to(self.prev_span); if !def.legacy { - self.sess.gated_spans.decl_macro.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::decl_macro, span); } Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec()))) diff --git a/src/libsyntax/parse/parser/pat.rs b/src/libsyntax/parse/parser/pat.rs index 969d5dd837480..cc8738edff7f5 100644 --- a/src/libsyntax/parse/parser/pat.rs +++ b/src/libsyntax/parse/parser/pat.rs @@ -8,9 +8,8 @@ use crate::mut_visit::{noop_visit_pat, noop_visit_mac, MutVisitor}; use crate::parse::token::{self}; use crate::print::pprust; use crate::source_map::{respan, Span, Spanned}; -use crate::symbol::kw; use crate::ThinVec; - +use syntax_pos::symbol::{kw, sym}; use errors::{Applicability, DiagnosticBuilder}; type Expected = Option<&'static str>; @@ -52,11 +51,8 @@ impl<'a> Parser<'a> { // and no other gated or-pattern has been parsed thus far, // then we should really gate the leading `|`. // This complicated procedure is done purely for diagnostics UX. - if gated_leading_vert { - let mut or_pattern_spans = self.sess.gated_spans.or_patterns.borrow_mut(); - if or_pattern_spans.is_empty() { - or_pattern_spans.push(leading_vert_span); - } + if gated_leading_vert && self.sess.gated_spans.is_ungated(sym::or_patterns) { + self.sess.gated_spans.gate(sym::or_patterns, leading_vert_span); } Ok(pat) @@ -117,7 +113,7 @@ impl<'a> Parser<'a> { // Feature gate the or-pattern if instructed: if gate_or == GateOr::Yes { - self.sess.gated_spans.or_patterns.borrow_mut().push(or_pattern_span); + self.sess.gated_spans.gate(sym::or_patterns, or_pattern_span); } Ok(self.mk_pat(or_pattern_span, PatKind::Or(pats))) @@ -325,7 +321,7 @@ impl<'a> Parser<'a> { } else if self.eat_keyword(kw::Box) { // Parse `box pat` let pat = self.parse_pat_with_range_pat(false, None)?; - self.sess.gated_spans.box_patterns.borrow_mut().push(lo.to(self.prev_span)); + self.sess.gated_spans.gate(sym::box_patterns, lo.to(self.prev_span)); PatKind::Box(pat) } else if self.can_be_ident_pat() { // Parse `ident @ pat` @@ -612,7 +608,7 @@ impl<'a> Parser<'a> { } fn excluded_range_end(&self, span: Span) -> RangeEnd { - self.sess.gated_spans.exclusive_range_pattern.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::exclusive_range_pattern, span); RangeEnd::Excluded } diff --git a/src/libsyntax/parse/parser/path.rs b/src/libsyntax/parse/parser/path.rs index f9944e36e2f60..4438d61d9eedd 100644 --- a/src/libsyntax/parse/parser/path.rs +++ b/src/libsyntax/parse/parser/path.rs @@ -5,7 +5,7 @@ use crate::ast::{self, QSelf, Path, PathSegment, Ident, ParenthesizedArgs, Angle use crate::ast::{AnonConst, GenericArg, AssocTyConstraint, AssocTyConstraintKind, BlockCheckMode}; use crate::parse::token::{self, Token}; use crate::source_map::{Span, BytePos}; -use crate::symbol::kw; +use syntax_pos::symbol::{kw, sym}; use std::mem; use log::debug; @@ -426,7 +426,7 @@ impl<'a> Parser<'a> { // Gate associated type bounds, e.g., `Iterator`. if let AssocTyConstraintKind::Bound { .. } = kind { - self.sess.gated_spans.associated_type_bounds.borrow_mut().push(span); + self.sess.gated_spans.gate(sym::associated_type_bounds, span); } constraints.push(AssocTyConstraint { diff --git a/src/libsyntax/sess.rs b/src/libsyntax/sess.rs index 30f8c56a05619..faad3e4af1e46 100644 --- a/src/libsyntax/sess.rs +++ b/src/libsyntax/sess.rs @@ -19,39 +19,53 @@ use std::str; /// Collected spans during parsing for places where a certain feature was /// used and should be feature gated accordingly in `check_crate`. #[derive(Default)] -crate struct GatedSpans { - /// Spans collected for gating `let_chains`, e.g. `if a && let b = c {}`. - crate let_chains: Lock>, - /// Spans collected for gating `async_closure`, e.g. `async || ..`. - crate async_closure: Lock>, - /// Spans collected for gating `yield e?` expressions (`generators` gate). - crate yields: Lock>, - /// Spans collected for gating `or_patterns`, e.g. `Some(Foo | Bar)`. - crate or_patterns: Lock>, - /// Spans collected for gating `const_extern_fn`, e.g. `const extern fn foo`. - crate const_extern_fn: Lock>, - /// Spans collected for gating `trait_alias`, e.g. `trait Foo = Ord + Eq;`. - pub trait_alias: Lock>, - /// Spans collected for gating `associated_type_bounds`, e.g. `Iterator`. - pub associated_type_bounds: Lock>, - /// Spans collected for gating `crate_visibility_modifier`, e.g. `crate fn`. - pub crate_visibility_modifier: Lock>, - /// Spans collected for gating `const_generics`, e.g. `const N: usize`. - pub const_generics: Lock>, - /// Spans collected for gating `decl_macro`, e.g. `macro m() {}`. - pub decl_macro: Lock>, - /// Spans collected for gating `box_patterns`, e.g. `box 0`. - pub box_patterns: Lock>, - /// Spans collected for gating `exclusive_range_pattern`, e.g. `0..2`. - pub exclusive_range_pattern: Lock>, - /// Spans collected for gating `try_blocks`, e.g. `try { a? + b? }`. - pub try_blocks: Lock>, - /// Spans collected for gating `label_break_value`, e.g. `'label: { ... }`. - pub label_break_value: Lock>, - /// Spans collected for gating `box_syntax`, e.g. `box $expr`. - pub box_syntax: Lock>, - /// Spans collected for gating `type_ascription`, e.g. `42: usize`. - pub type_ascription: Lock>, +pub struct GatedSpans { + pub spans: Lock>>, +} + +impl GatedSpans { + /// Feature gate the given `span` under the given `feature` + /// which is same `Symbol` used in `active.rs`. + pub fn gate(&self, feature: Symbol, span: Span) { + self.spans + .borrow_mut() + .entry(feature) + .or_default() + .push(span); + } + + /// Ungate the last span under the given `feature`. + /// Panics if the given `span` wasn't the last one. + /// + /// Using this is discouraged unless you have a really good reason to. + pub fn ungate_last(&self, feature: Symbol, span: Span) { + let removed_span = self.spans + .borrow_mut() + .entry(feature) + .or_default() + .pop() + .unwrap(); + debug_assert_eq!(span, removed_span); + } + + /// Is the provided `feature` gate ungated currently? + /// + /// Using this is discouraged unless you have a really good reason to. + pub fn is_ungated(&self, feature: Symbol) -> bool { + self.spans + .borrow() + .get(&feature) + .map_or(true, |spans| spans.is_empty()) + } + + /// Prepend the given set of `spans` onto the set in `self`. + pub fn merge(&self, mut spans: FxHashMap>) { + let mut inner = self.spans.borrow_mut(); + for (gate, mut gate_spans) in inner.drain() { + spans.entry(gate).or_default().append(&mut gate_spans); + } + *inner = spans; + } } /// Info about a parsing session. @@ -72,7 +86,7 @@ pub struct ParseSess { /// analysis. pub ambiguous_block_expr_parse: Lock>, pub injected_crate_name: Once, - crate gated_spans: GatedSpans, + pub gated_spans: GatedSpans, /// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors. pub reached_eof: Lock, } diff --git a/src/libsyntax_expand/mbe/macro_rules.rs b/src/libsyntax_expand/mbe/macro_rules.rs index 7a772b0d31dab..5571990740317 100644 --- a/src/libsyntax_expand/mbe/macro_rules.rs +++ b/src/libsyntax_expand/mbe/macro_rules.rs @@ -29,7 +29,7 @@ use syntax_pos::Span; use rustc_data_structures::fx::FxHashMap; use std::borrow::Cow; use std::collections::hash_map::Entry; -use std::slice; +use std::{mem, slice}; use errors::Applicability; use rustc_data_structures::sync::Lrc; @@ -182,7 +182,6 @@ fn generic_extension<'cx>( // 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 let lhs_tt = match *lhs { @@ -190,8 +189,18 @@ fn generic_extension<'cx>( _ => cx.span_bug(sp, "malformed macro lhs"), }; + // Take a snapshot of the state of pre-expansion gating at this point. + // This is used so that if a matcher is not `Success(..)`ful, + // then the spans which became gated when parsing the unsucessful matcher + // are not recorded. On the first `Success(..)`ful matcher, the spans are merged. + let mut gated_spans_snaphot = mem::take(&mut *cx.parse_sess.gated_spans.spans.borrow_mut()); + match parse_tt(cx, lhs_tt, arg.clone()) { Success(named_matches) => { + // The matcher was `Success(..)`ful. + // Merge the gated spans from parsing the matcher with the pre-existing ones. + cx.parse_sess.gated_spans.merge(gated_spans_snaphot); + let rhs = match rhses[i] { // ignore delimiters mbe::TokenTree::Delimited(_, ref delimed) => delimed.tts.clone(), @@ -248,6 +257,10 @@ fn generic_extension<'cx>( }, Error(err_sp, ref msg) => cx.span_fatal(err_sp.substitute_dummy(sp), &msg[..]), } + + // The matcher was not `Success(..)`ful. + // Restore to the state before snapshotting and maybe try again. + mem::swap(&mut gated_spans_snaphot, &mut cx.parse_sess.gated_spans.spans.borrow_mut()); } let (token, label) = best_failure.expect("ran no matchers"); diff --git a/src/test/ui/parser/issue-65846-rollback-gating-failing-matcher.rs b/src/test/ui/parser/issue-65846-rollback-gating-failing-matcher.rs new file mode 100644 index 0000000000000..9d68a7bffdeee --- /dev/null +++ b/src/test/ui/parser/issue-65846-rollback-gating-failing-matcher.rs @@ -0,0 +1,14 @@ +// run-pass + +// Test that failing macro matchers will not cause pre-expansion errors +// even though they use a feature that is pre-expansion gated. + +macro_rules! m { + ($e:expr) => { 0 }; // This fails on the input below due to `, foo`. + ($e:expr,) => { 1 }; // This also fails to match due to `foo`. + (box $e:expr, foo) => { 2 }; // Successful matcher, we should get `2`. +} + +fn main() { + assert_eq!(2, m!(box 42, foo)); +}