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-rw-r--r--compiler/rustc_parse/src/errors.rs22
-rw-r--r--compiler/rustc_parse/src/lexer/mod.rs57
-rw-r--r--compiler/rustc_parse/src/lexer/unescape_error_reporting.rs20
-rw-r--r--compiler/rustc_parse/src/parser/expr.rs127
4 files changed, 162 insertions, 64 deletions
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 5cad3a568ee..20ebfc6691b 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -1987,6 +1987,17 @@ pub enum UnknownPrefixSugg {
         style = "verbose"
     )]
     Whitespace(#[primary_span] Span),
+    #[multipart_suggestion(
+        parse_suggestion_str,
+        applicability = "maybe-incorrect",
+        style = "verbose"
+    )]
+    MeantStr {
+        #[suggestion_part(code = "\"")]
+        start: Span,
+        #[suggestion_part(code = "\"")]
+        end: Span,
+    },
 }
 
 #[derive(Diagnostic)]
@@ -2198,12 +2209,21 @@ pub enum MoreThanOneCharSugg {
         ch: String,
     },
     #[suggestion(parse_use_double_quotes, code = "{sugg}", applicability = "machine-applicable")]
-    Quotes {
+    QuotesFull {
         #[primary_span]
         span: Span,
         is_byte: bool,
         sugg: String,
     },
+    #[multipart_suggestion(parse_use_double_quotes, applicability = "machine-applicable")]
+    Quotes {
+        #[suggestion_part(code = "{prefix}\"")]
+        start: Span,
+        #[suggestion_part(code = "\"")]
+        end: Span,
+        is_byte: bool,
+        prefix: &'static str,
+    },
 }
 
 #[derive(Subdiagnostic)]
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index f57945a52df..63b2b47630b 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -63,6 +63,7 @@ pub(crate) fn parse_token_trees<'psess, 'src>(
         cursor,
         override_span,
         nbsp_is_whitespace: false,
+        last_lifetime: None,
     };
     let (stream, res, unmatched_delims) =
         tokentrees::TokenTreesReader::parse_all_token_trees(string_reader);
@@ -105,6 +106,10 @@ struct StringReader<'psess, 'src> {
     /// in this file, it's safe to treat further occurrences of the non-breaking
     /// space character as whitespace.
     nbsp_is_whitespace: bool,
+
+    /// Track the `Span` for the leading `'` of the last lifetime. Used for
+    /// diagnostics to detect possible typo where `"` was meant.
+    last_lifetime: Option<Span>,
 }
 
 impl<'psess, 'src> StringReader<'psess, 'src> {
@@ -130,6 +135,18 @@ impl<'psess, 'src> StringReader<'psess, 'src> {
 
             debug!("next_token: {:?}({:?})", token.kind, self.str_from(start));
 
+            if let rustc_lexer::TokenKind::Semi
+            | rustc_lexer::TokenKind::LineComment { .. }
+            | rustc_lexer::TokenKind::BlockComment { .. }
+            | rustc_lexer::TokenKind::CloseParen
+            | rustc_lexer::TokenKind::CloseBrace
+            | rustc_lexer::TokenKind::CloseBracket = token.kind
+            {
+                // Heuristic: we assume that it is unlikely we're dealing with an unterminated
+                // string surrounded by single quotes.
+                self.last_lifetime = None;
+            }
+
             // Now "cook" the token, converting the simple `rustc_lexer::TokenKind` enum into a
             // rich `rustc_ast::TokenKind`. This turns strings into interned symbols and runs
             // additional validation.
@@ -247,6 +264,7 @@ impl<'psess, 'src> StringReader<'psess, 'src> {
                     // expansion purposes. See #12512 for the gory details of why
                     // this is necessary.
                     let lifetime_name = self.str_from(start);
+                    self.last_lifetime = Some(self.mk_sp(start, start + BytePos(1)));
                     if starts_with_number {
                         let span = self.mk_sp(start, self.pos);
                         self.dcx().struct_err("lifetimes cannot start with a number")
@@ -395,10 +413,21 @@ impl<'psess, 'src> StringReader<'psess, 'src> {
         match kind {
             rustc_lexer::LiteralKind::Char { terminated } => {
                 if !terminated {
-                    self.dcx()
+                    let mut err = self
+                        .dcx()
                         .struct_span_fatal(self.mk_sp(start, end), "unterminated character literal")
-                        .with_code(E0762)
-                        .emit()
+                        .with_code(E0762);
+                    if let Some(lt_sp) = self.last_lifetime {
+                        err.multipart_suggestion(
+                            "if you meant to write a string literal, use double quotes",
+                            vec![
+                                (lt_sp, "\"".to_string()),
+                                (self.mk_sp(start, start + BytePos(1)), "\"".to_string()),
+                            ],
+                            Applicability::MaybeIncorrect,
+                        );
+                    }
+                    err.emit()
                 }
                 self.cook_unicode(token::Char, Mode::Char, start, end, 1, 1) // ' '
             }
@@ -669,15 +698,33 @@ impl<'psess, 'src> StringReader<'psess, 'src> {
         let expn_data = prefix_span.ctxt().outer_expn_data();
 
         if expn_data.edition >= Edition::Edition2021 {
+            let mut silence = false;
             // In Rust 2021, this is a hard error.
             let sugg = if prefix == "rb" {
                 Some(errors::UnknownPrefixSugg::UseBr(prefix_span))
             } else if expn_data.is_root() {
-                Some(errors::UnknownPrefixSugg::Whitespace(prefix_span.shrink_to_hi()))
+                if self.cursor.first() == '\''
+                    && let Some(start) = self.last_lifetime
+                    && self.cursor.third() != '\''
+                {
+                    // An "unclosed `char`" error will be emitted already, silence redundant error.
+                    silence = true;
+                    Some(errors::UnknownPrefixSugg::MeantStr {
+                        start,
+                        end: self.mk_sp(self.pos, self.pos + BytePos(1)),
+                    })
+                } else {
+                    Some(errors::UnknownPrefixSugg::Whitespace(prefix_span.shrink_to_hi()))
+                }
             } else {
                 None
             };
-            self.dcx().emit_err(errors::UnknownPrefix { span: prefix_span, prefix, sugg });
+            let err = errors::UnknownPrefix { span: prefix_span, prefix, sugg };
+            if silence {
+                self.dcx().create_err(err).delay_as_bug();
+            } else {
+                self.dcx().emit_err(err);
+            }
         } else {
             // Before Rust 2021, only emit a lint for migration.
             self.psess.buffer_lint_with_diagnostic(
diff --git a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
index 3ebad6a9fd7..fa242a32a18 100644
--- a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
+++ b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
@@ -95,11 +95,21 @@ pub(crate) fn emit_unescape_error(
                     }
                     escaped.push(c);
                 }
-                let sugg = format!("{prefix}\"{escaped}\"");
-                MoreThanOneCharSugg::Quotes {
-                    span: full_lit_span,
-                    is_byte: mode == Mode::Byte,
-                    sugg,
+                if escaped.len() != lit.len() || full_lit_span.is_empty() {
+                    let sugg = format!("{prefix}\"{escaped}\"");
+                    MoreThanOneCharSugg::QuotesFull {
+                        span: full_lit_span,
+                        is_byte: mode == Mode::Byte,
+                        sugg,
+                    }
+                } else {
+                    MoreThanOneCharSugg::Quotes {
+                        start: full_lit_span
+                            .with_hi(full_lit_span.lo() + BytePos((prefix.len() + 1) as u32)),
+                        end: full_lit_span.with_lo(full_lit_span.hi() - BytePos(1)),
+                        is_byte: mode == Mode::Byte,
+                        prefix,
+                    }
                 }
             });
             dcx.emit_err(UnescapeError::MoreThanOneChar {
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index d175d1c04c8..7e317c3df14 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -11,12 +11,11 @@ use crate::errors;
 use crate::maybe_recover_from_interpolated_ty_qpath;
 use ast::mut_visit::{noop_visit_expr, MutVisitor};
 use ast::token::IdentIsRaw;
-use ast::{CoroutineKind, ForLoopKind, GenBlockKind, Pat, Path, PathSegment};
+use ast::{CoroutineKind, ForLoopKind, GenBlockKind, MatchKind, Pat, Path, PathSegment};
 use core::mem;
 use core::ops::ControlFlow;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
-use rustc_ast::tokenstream::Spacing;
 use rustc_ast::util::case::Case;
 use rustc_ast::util::classify;
 use rustc_ast::util::parser::{prec_let_scrutinee_needs_par, AssocOp, Fixity};
@@ -999,13 +998,57 @@ impl<'a> Parser<'a> {
     }
 
     pub fn parse_dot_suffix_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
+        // At this point we've consumed something like `expr.` and `self.token` holds the token
+        // after the dot.
         match self.token.uninterpolate().kind {
             token::Ident(..) => self.parse_dot_suffix(base, lo),
             token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) => {
-                Ok(self.parse_expr_tuple_field_access(lo, base, symbol, suffix, None))
+                let ident_span = self.token.span;
+                self.bump();
+                Ok(self.mk_expr_tuple_field_access(lo, ident_span, base, symbol, suffix))
             }
             token::Literal(token::Lit { kind: token::Float, symbol, suffix }) => {
-                Ok(self.parse_expr_tuple_field_access_float(lo, base, symbol, suffix))
+                Ok(match self.break_up_float(symbol, self.token.span) {
+                    // 1e2
+                    DestructuredFloat::Single(sym, _sp) => {
+                        // `foo.1e2`: a single complete dot access, fully consumed. We end up with
+                        // the `1e2` token in `self.prev_token` and the following token in
+                        // `self.token`.
+                        let ident_span = self.token.span;
+                        self.bump();
+                        self.mk_expr_tuple_field_access(lo, ident_span, base, sym, suffix)
+                    }
+                    // 1.
+                    DestructuredFloat::TrailingDot(sym, ident_span, dot_span) => {
+                        // `foo.1.`: a single complete dot access and the start of another.
+                        // We end up with the `sym` (`1`) token in `self.prev_token` and a dot in
+                        // `self.token`.
+                        assert!(suffix.is_none());
+                        self.token = Token::new(token::Ident(sym, IdentIsRaw::No), ident_span);
+                        self.bump_with((Token::new(token::Dot, dot_span), self.token_spacing));
+                        self.mk_expr_tuple_field_access(lo, ident_span, base, sym, None)
+                    }
+                    // 1.2 | 1.2e3
+                    DestructuredFloat::MiddleDot(
+                        sym1,
+                        ident1_span,
+                        _dot_span,
+                        sym2,
+                        ident2_span,
+                    ) => {
+                        // `foo.1.2` (or `foo.1.2e3`): two complete dot accesses. We end up with
+                        // the `sym2` (`2` or `2e3`) token in `self.prev_token` and the following
+                        // token in `self.token`.
+                        let next_token2 =
+                            Token::new(token::Ident(sym2, IdentIsRaw::No), ident2_span);
+                        self.bump_with((next_token2, self.token_spacing));
+                        self.bump();
+                        let base1 =
+                            self.mk_expr_tuple_field_access(lo, ident1_span, base, sym1, None);
+                        self.mk_expr_tuple_field_access(lo, ident2_span, base1, sym2, suffix)
+                    }
+                    DestructuredFloat::Error => base,
+                })
             }
             _ => {
                 self.error_unexpected_after_dot();
@@ -1119,41 +1162,6 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn parse_expr_tuple_field_access_float(
-        &mut self,
-        lo: Span,
-        base: P<Expr>,
-        float: Symbol,
-        suffix: Option<Symbol>,
-    ) -> P<Expr> {
-        match self.break_up_float(float, self.token.span) {
-            // 1e2
-            DestructuredFloat::Single(sym, _sp) => {
-                self.parse_expr_tuple_field_access(lo, base, sym, suffix, None)
-            }
-            // 1.
-            DestructuredFloat::TrailingDot(sym, ident_span, dot_span) => {
-                assert!(suffix.is_none());
-                self.token = Token::new(token::Ident(sym, IdentIsRaw::No), ident_span);
-                let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
-                self.parse_expr_tuple_field_access(lo, base, sym, None, Some(next_token))
-            }
-            // 1.2 | 1.2e3
-            DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span) => {
-                self.token = Token::new(token::Ident(symbol1, IdentIsRaw::No), ident1_span);
-                // This needs to be `Spacing::Alone` to prevent regressions.
-                // See issue #76399 and PR #76285 for more details
-                let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
-                let base1 =
-                    self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
-                let next_token2 = Token::new(token::Ident(symbol2, IdentIsRaw::No), ident2_span);
-                self.bump_with((next_token2, self.token_spacing)); // `.`
-                self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
-            }
-            DestructuredFloat::Error => base,
-        }
-    }
-
     /// Parse the field access used in offset_of, matched by `$(e:expr)+`.
     /// Currently returns a list of idents. However, it should be possible in
     /// future to also do array indices, which might be arbitrary expressions.
@@ -1255,24 +1263,18 @@ impl<'a> Parser<'a> {
         Ok(fields.into_iter().collect())
     }
 
-    fn parse_expr_tuple_field_access(
+    fn mk_expr_tuple_field_access(
         &mut self,
         lo: Span,
+        ident_span: Span,
         base: P<Expr>,
         field: Symbol,
         suffix: Option<Symbol>,
-        next_token: Option<(Token, Spacing)>,
     ) -> P<Expr> {
-        match next_token {
-            Some(next_token) => self.bump_with(next_token),
-            None => self.bump(),
-        }
-        let span = self.prev_token.span;
-        let field = ExprKind::Field(base, Ident::new(field, span));
         if let Some(suffix) = suffix {
-            self.expect_no_tuple_index_suffix(span, suffix);
+            self.expect_no_tuple_index_suffix(ident_span, suffix);
         }
-        self.mk_expr(lo.to(span), field)
+        self.mk_expr(lo.to(ident_span), ExprKind::Field(base, Ident::new(field, ident_span)))
     }
 
     /// Parse a function call expression, `expr(...)`.
@@ -1379,6 +1381,13 @@ impl<'a> Parser<'a> {
             return Ok(self.mk_await_expr(self_arg, lo));
         }
 
+        // Post-fix match
+        if self.eat_keyword(kw::Match) {
+            let match_span = self.prev_token.span;
+            self.psess.gated_spans.gate(sym::postfix_match, match_span);
+            return self.parse_match_block(lo, match_span, self_arg, MatchKind::Postfix);
+        }
+
         let fn_span_lo = self.token.span;
         let mut seg = self.parse_path_segment(PathStyle::Expr, None)?;
         self.check_trailing_angle_brackets(&seg, &[&token::OpenDelim(Delimiter::Parenthesis)]);
@@ -2894,8 +2903,20 @@ impl<'a> Parser<'a> {
     /// Parses a `match ... { ... }` expression (`match` token already eaten).
     fn parse_expr_match(&mut self) -> PResult<'a, P<Expr>> {
         let match_span = self.prev_token.span;
-        let lo = self.prev_token.span;
         let scrutinee = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
+
+        self.parse_match_block(match_span, match_span, scrutinee, MatchKind::Prefix)
+    }
+
+    /// Parses the block of a `match expr { ... }` or a `expr.match { ... }`
+    /// expression. This is after the match token and scrutinee are eaten
+    fn parse_match_block(
+        &mut self,
+        lo: Span,
+        match_span: Span,
+        scrutinee: P<Expr>,
+        match_kind: MatchKind,
+    ) -> PResult<'a, P<Expr>> {
         if let Err(mut e) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
             if self.token == token::Semi {
                 e.span_suggestion_short(
@@ -2938,7 +2959,7 @@ impl<'a> Parser<'a> {
                     });
                     return Ok(self.mk_expr_with_attrs(
                         span,
-                        ExprKind::Match(scrutinee, arms),
+                        ExprKind::Match(scrutinee, arms, match_kind),
                         attrs,
                     ));
                 }
@@ -2946,7 +2967,7 @@ impl<'a> Parser<'a> {
         }
         let hi = self.token.span;
         self.bump();
-        Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms), attrs))
+        Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms, match_kind), attrs))
     }
 
     /// Attempt to recover from match arm body with statements and no surrounding braces.
@@ -3955,7 +3976,7 @@ impl MutVisitor for CondChecker<'_> {
             | ExprKind::While(_, _, _)
             | ExprKind::ForLoop { .. }
             | ExprKind::Loop(_, _, _)
-            | ExprKind::Match(_, _)
+            | ExprKind::Match(_, _, _)
             | ExprKind::Closure(_)
             | ExprKind::Block(_, _)
             | ExprKind::Gen(_, _, _)