use crate::mbe::{self, TokenTree};
use rustc_ast::token::{self, DocComment, Nonterminal, Token};
-use rustc_parse::parser::Parser;
+use rustc_parse::parser::{OrPatNonterminalMode, Parser};
use rustc_session::parse::ParseSess;
-use rustc_span::symbol::MacroRulesNormalizedIdent;
+use rustc_span::{edition::Edition, symbol::MacroRulesNormalizedIdent};
use smallvec::{smallvec, SmallVec};
}
}
+/// In edition 2015/18, `:pat` can only match `pat<no_top_alt>` because otherwise, we have
+/// breakage. As of edition 2021, `:pat` matches `top_pat`.
+///
+/// See <https://github.com/rust-lang/rust/issues/54883> for more info.
+fn or_pat_mode(edition: Edition) -> OrPatNonterminalMode {
+ match edition {
+ Edition::Edition2015 | Edition::Edition2018 => OrPatNonterminalMode::NoTopAlt,
+ // FIXME(mark-i-m): uncomment this when edition 2021 machinery is added.
+ // Edition::Edition2021 => OrPatNonterminalMode::TopPat,
+ }
+}
+
/// Process the matcher positions of `cur_items` until it is empty. In the process, this will
/// produce more items in `next_items`, `eof_items`, and `bb_items`.
///
// We need to match a metavar with a valid ident... call out to the black-box
// parser by adding an item to `bb_items`.
- TokenTree::MetaVarDecl(_, _, kind) => {
- // Built-in nonterminals never start with these tokens,
- // so we can eliminate them from consideration.
- if Parser::nonterminal_may_begin_with(kind, token) {
+ TokenTree::MetaVarDecl(span, _, kind) => {
+ // Built-in nonterminals never start with these tokens, so we can eliminate
+ // them from consideration.
+ //
+ // We use the span of the metavariable declaration to determine any
+ // edition-specific matching behavior for non-terminals.
+ if Parser::nonterminal_may_begin_with(kind, token, or_pat_mode(span.edition()))
+ {
bb_items.push(item);
}
}
let mut item = bb_items.pop().unwrap();
if let TokenTree::MetaVarDecl(span, _, kind) = item.top_elts.get_tt(item.idx) {
let match_cur = item.match_cur;
- let nt = match parser.to_mut().parse_nonterminal(kind) {
+ // We use the span of the metavariable declaration to determine any
+ // edition-specific matching behavior for non-terminals.
+ let nt = match parser.to_mut().parse_nonterminal(kind, or_pat_mode(span.edition()))
+ {
Err(mut err) => {
err.span_label(
span,
-use super::pat::{GateOr, PARAM_EXPECTED};
+use super::pat::{GateOr, RecoverComma, PARAM_EXPECTED};
use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
use super::{BlockMode, Parser, PathStyle, Restrictions, TokenType};
use super::{SemiColonMode, SeqSep, TokenExpectType};
/// The `let` token has already been eaten.
fn parse_let_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
let lo = self.prev_token.span;
- let pat = self.parse_top_pat(GateOr::No)?;
+ let pat = self.parse_top_pat(GateOr::No, RecoverComma::Yes)?;
self.expect(&token::Eq)?;
let expr = self.with_res(self.restrictions | Restrictions::NO_STRUCT_LITERAL, |this| {
this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into())
_ => None,
};
- let pat = self.parse_top_pat(GateOr::Yes)?;
+ let pat = self.parse_top_pat(GateOr::Yes, RecoverComma::Yes)?;
if !self.eat_keyword(kw::In) {
self.error_missing_in_for_loop();
}
pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
let attrs = self.parse_outer_attributes()?;
let lo = self.token.span;
- let pat = self.parse_top_pat(GateOr::No)?;
+ let pat = self.parse_top_pat(GateOr::No, RecoverComma::Yes)?;
let guard = if self.eat_keyword(kw::If) {
let if_span = self.prev_token.span;
let cond = self.parse_expr()?;
use crate::lexer::UnmatchedBrace;
pub use diagnostics::AttemptLocalParseRecovery;
use diagnostics::Error;
+pub use pat::OrPatNonterminalMode;
pub use path::PathStyle;
use rustc_ast::ptr::P;
use rustc_errors::PResult;
use rustc_span::symbol::{kw, Ident};
+use crate::parser::pat::{GateOr, OrPatNonterminalMode, RecoverComma};
use crate::parser::{FollowedByType, Parser, PathStyle};
impl<'a> Parser<'a> {
///
/// Returning `false` is a *stability guarantee* that such a matcher will *never* begin with that
/// token. Be conservative (return true) if not sure.
- pub fn nonterminal_may_begin_with(kind: NonterminalKind, token: &Token) -> bool {
+ pub fn nonterminal_may_begin_with(
+ kind: NonterminalKind,
+ token: &Token,
+ or_pat_mode: OrPatNonterminalMode,
+ ) -> bool {
/// Checks whether the non-terminal may contain a single (non-keyword) identifier.
fn may_be_ident(nt: &token::Nonterminal) -> bool {
match *nt {
token::ModSep | // path
token::Lt | // path (UFCS constant)
token::BinOp(token::Shl) => true, // path (double UFCS)
+ // leading vert `|` or-pattern
+ token::BinOp(token::Or) => matches!(or_pat_mode, OrPatNonterminalMode::TopPat),
token::Interpolated(ref nt) => may_be_ident(nt),
_ => false,
},
}
}
- pub fn parse_nonterminal(&mut self, kind: NonterminalKind) -> PResult<'a, Nonterminal> {
+ /// Parse a non-terminal (e.g. MBE `:pat` or `:ident`).
+ pub fn parse_nonterminal(
+ &mut self,
+ kind: NonterminalKind,
+ or_pat_mode: OrPatNonterminalMode,
+ ) -> PResult<'a, Nonterminal> {
// Any `Nonterminal` which stores its tokens (currently `NtItem` and `NtExpr`)
// needs to have them force-captured here.
// A `macro_rules!` invocation may pass a captured item/expr to a proc-macro,
}
}
NonterminalKind::Pat => {
- let (mut pat, tokens) = self.collect_tokens(|this| this.parse_pat(None))?;
+ let (mut pat, tokens) = self.collect_tokens(|this| match or_pat_mode {
+ OrPatNonterminalMode::TopPat => {
+ this.parse_top_pat(GateOr::Yes, RecoverComma::No)
+ }
+ OrPatNonterminalMode::NoTopAlt => this.parse_pat(None),
+ })?;
// We have have eaten an NtPat, which could already have tokens
if pat.tokens.is_none() {
pat.tokens = tokens;
/// Whether or not to recover a `,` when parsing or-patterns.
#[derive(PartialEq, Copy, Clone)]
-enum RecoverComma {
+pub(super) enum RecoverComma {
Yes,
No,
}
+/// Used when parsing a non-terminal (see `parse_nonterminal`) to determine if `:pat` should match
+/// `top_pat` or `pat<no_top_alt>`. See issue <https://github.com/rust-lang/rust/pull/78935>.
+pub enum OrPatNonterminalMode {
+ TopPat,
+ NoTopAlt,
+}
+
impl<'a> Parser<'a> {
/// Parses a pattern.
///
/// Entry point to the main pattern parser.
/// Corresponds to `top_pat` in RFC 2535 and allows or-pattern at the top level.
- pub(super) fn parse_top_pat(&mut self, gate_or: GateOr) -> PResult<'a, P<Pat>> {
+ pub(super) fn parse_top_pat(
+ &mut self,
+ gate_or: GateOr,
+ rc: RecoverComma,
+ ) -> PResult<'a, P<Pat>> {
// Allow a '|' before the pats (RFCs 1925, 2530, and 2535).
let gated_leading_vert = self.eat_or_separator(None) && gate_or == GateOr::Yes;
let leading_vert_span = self.prev_token.span;
// Parse the possibly-or-pattern.
- let pat = self.parse_pat_with_or(None, gate_or, RecoverComma::Yes)?;
+ let pat = self.parse_pat_with_or(None, gate_or, rc)?;
// If we parsed a leading `|` which should be gated,
// and no other gated or-pattern has been parsed thus far,
use super::attr::DEFAULT_INNER_ATTR_FORBIDDEN;
use super::diagnostics::{AttemptLocalParseRecovery, Error};
use super::expr::LhsExpr;
-use super::pat::GateOr;
+use super::pat::{GateOr, RecoverComma};
use super::path::PathStyle;
use super::{BlockMode, Parser, Restrictions, SemiColonMode};
use crate::maybe_whole;
/// Parses a local variable declaration.
fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> {
let lo = self.prev_token.span;
- let pat = self.parse_top_pat(GateOr::Yes)?;
+ let pat = self.parse_top_pat(GateOr::Yes, RecoverComma::Yes)?;
let (err, ty) = if self.eat(&token::Colon) {
// Save the state of the parser before parsing type normally, in case there is a `:`
--- /dev/null
+// run-pass
+// edition:2018
+
+macro_rules! pat_bar {
+ ($p:pat | $p2:pat) => {{
+ match Some(1u8) {
+ $p | $p2 => {}
+ _ => {}
+ }
+ }};
+}
+
+fn main() {
+ pat_bar!(Some(1u8) | None);
+}
($p:pat in $e:expr) => {{
let mut iter = $e.into_iter();
while let $p = iter.next() {}
- }}
+ }};
}
macro_rules! pat_if {
($p:pat if $e:expr) => {{
match Some(1u8) {
- $p if $e => {},
+ $p if $e => {}
_ => {}
}
- }}
-}
-
-macro_rules! pat_bar {
- ($p:pat | $p2:pat) => {{
- match Some(1u8) {
- $p | $p2 => {},
- _ => {}
- }
- }}
+ }};
}
fn main() {
pat_in!(Some(_) in 0..10);
pat_if!(Some(x) if x > 0);
- pat_bar!(Some(1u8) | None);
}
--- /dev/null
+// Test that :pat doesn't accept top-level or-patterns in edition 2018.
+
+// edition:2018
+
+#![feature(or_patterns)]
+
+fn main() {}
+
+// Test the `pat` macro fragment parser:
+macro_rules! accept_pat {
+ ($p:pat) => {};
+}
+
+accept_pat!(p | q); //~ ERROR no rules expected the token `|`
+accept_pat!(|p| q); //~ ERROR no rules expected the token `|`
--- /dev/null
+error: no rules expected the token `|`
+ --> $DIR/or-patterns-syntactic-fail-2018.rs:14:15
+ |
+LL | macro_rules! accept_pat {
+ | ----------------------- when calling this macro
+...
+LL | accept_pat!(p | q);
+ | ^ no rules expected this token in macro call
+
+error: no rules expected the token `|`
+ --> $DIR/or-patterns-syntactic-fail-2018.rs:15:13
+ |
+LL | macro_rules! accept_pat {
+ | ----------------------- when calling this macro
+...
+LL | accept_pat!(|p| q);
+ | ^ no rules expected this token in macro call
+
+error: aborting due to 2 previous errors
+
fn main() {}
-// Test the `pat` macro fragment parser:
-macro_rules! accept_pat {
- ($p:pat) => {}
-}
-
-accept_pat!(p | q); //~ ERROR no rules expected the token `|`
-accept_pat!(| p | q); //~ ERROR no rules expected the token `|`
-
-// Non-macro tests:
-
enum E { A, B }
use E::*;
error: an or-pattern parameter must be wrapped in parenthesis
- --> $DIR/or-patterns-syntactic-fail.rs:27:13
+ --> $DIR/or-patterns-syntactic-fail.rs:17:13
|
LL | fn fun1(A | B: E) {}
| ^^^^^ help: wrap the pattern in parenthesis: `(A | B)`
error: a leading `|` is not allowed in a parameter pattern
- --> $DIR/or-patterns-syntactic-fail.rs:29:13
+ --> $DIR/or-patterns-syntactic-fail.rs:19:13
|
LL | fn fun2(| A | B: E) {}
| ^ help: remove the `|`
error: an or-pattern parameter must be wrapped in parenthesis
- --> $DIR/or-patterns-syntactic-fail.rs:29:15
+ --> $DIR/or-patterns-syntactic-fail.rs:19:15
|
LL | fn fun2(| A | B: E) {}
| ^^^^^ help: wrap the pattern in parenthesis: `(A | B)`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:40:11
+ --> $DIR/or-patterns-syntactic-fail.rs:30:11
|
LL | let ( | A | B) = E::A;
| ^ help: remove the `|`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:41:11
+ --> $DIR/or-patterns-syntactic-fail.rs:31:11
|
LL | let ( | A | B,) = (E::B,);
| ^ help: remove the `|`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:42:11
+ --> $DIR/or-patterns-syntactic-fail.rs:32:11
|
LL | let [ | A | B ] = [E::A];
| ^ help: remove the `|`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:43:13
+ --> $DIR/or-patterns-syntactic-fail.rs:33:13
|
LL | let TS( | A | B );
| ^ help: remove the `|`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:44:17
+ --> $DIR/or-patterns-syntactic-fail.rs:34:17
|
LL | let NS { f: | A | B };
| ^ help: remove the `|`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:46:11
+ --> $DIR/or-patterns-syntactic-fail.rs:36:11
|
LL | let ( || A | B) = E::A;
| ^^ help: remove the `||`
= note: alternatives in or-patterns are separated with `|`, not `||`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:47:11
+ --> $DIR/or-patterns-syntactic-fail.rs:37:11
|
LL | let [ || A | B ] = [E::A];
| ^^ help: remove the `||`
= note: alternatives in or-patterns are separated with `|`, not `||`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:48:13
+ --> $DIR/or-patterns-syntactic-fail.rs:38:13
|
LL | let TS( || A | B );
| ^^ help: remove the `||`
= note: alternatives in or-patterns are separated with `|`, not `||`
error: a leading `|` is only allowed in a top-level pattern
- --> $DIR/or-patterns-syntactic-fail.rs:49:17
+ --> $DIR/or-patterns-syntactic-fail.rs:39:17
|
LL | let NS { f: || A | B };
| ^^ help: remove the `||`
|
= note: alternatives in or-patterns are separated with `|`, not `||`
-error: no rules expected the token `|`
- --> $DIR/or-patterns-syntactic-fail.rs:13:15
- |
-LL | macro_rules! accept_pat {
- | ----------------------- when calling this macro
-...
-LL | accept_pat!(p | q);
- | ^ no rules expected this token in macro call
-
-error: no rules expected the token `|`
- --> $DIR/or-patterns-syntactic-fail.rs:14:13
- |
-LL | macro_rules! accept_pat {
- | ----------------------- when calling this macro
-...
-LL | accept_pat!(| p | q);
- | ^ no rules expected this token in macro call
-
error[E0369]: no implementation for `E | ()`
- --> $DIR/or-patterns-syntactic-fail.rs:23:22
+ --> $DIR/or-patterns-syntactic-fail.rs:13:22
|
LL | let _ = |A | B: E| ();
| ----^ -- ()
= note: an implementation of `std::ops::BitOr` might be missing for `E`
error[E0308]: mismatched types
- --> $DIR/or-patterns-syntactic-fail.rs:51:36
+ --> $DIR/or-patterns-syntactic-fail.rs:41:36
|
LL | let recovery_witness: String = 0;
| ------ ^
| | help: try using a conversion method: `0.to_string()`
| expected due to this
-error: aborting due to 16 previous errors
+error: aborting due to 14 previous errors
Some errors have detailed explanations: E0308, E0369.
For more information about an error, try `rustc --explain E0308`.
--- /dev/null
+// Tests that :pat in macros in edition 2021 allows top-level or-patterns.
+
+// run-pass
+// ignore-test
+// edition:2021
+// FIXME(mark-i-m): unignore when 2021 machinery is in place.
+
+macro_rules! accept_pat {
+ ($p:pat) => {};
+}
+
+accept_pat!(p | q);
+
+fn main() {}
--- /dev/null
+// run-pass
+// edition:2021
+// ignore-test
+// FIXME(mark-i-m): enable this test again when 2021 machinery is available
+
+#![feature(or_patterns)]
+
+use Foo::*;
+
+#[derive(Eq, PartialEq, Debug)]
+enum Foo {
+ A(u64),
+ B(u64),
+ C,
+ D,
+}
+
+macro_rules! foo {
+ ($orpat:pat, $val:expr) => {
+ match $val {
+ x @ ($orpat) => x, // leading vert would not be allowed in $orpat
+ _ => B(0xDEADBEEFu64),
+ }
+ };
+}
+
+macro_rules! bar {
+ ($orpat:pat, $val:expr) => {
+ match $val {
+ $orpat => 42, // leading vert allowed here
+ _ => 0xDEADBEEFu64,
+ }
+ };
+}
+
+fn main() {
+ // Test or-pattern.
+ let y = foo!(A(_)|B(_), A(32));
+ assert_eq!(y, A(32));
+
+ // Leading vert in or-pattern.
+ let y = bar!(|C| D, C);
+ assert_eq!(y, 42u64);
+}
projects / rust.git / commitdiff