Merge from rustc

16 files changed, 84 insertions, 95 deletions

diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 6c1fcbe06fc..7566a4d5066 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -3,7 +3,7 @@ use std::borrow::Cow;
 use rustc_ast::token::Token;
 use rustc_ast::{Path, Visibility};
 use rustc_errors::{
-    codes::*, Applicability, Diag, DiagCtxt, Diagnostic, EmissionGuarantee, Level,
+    codes::*, Applicability, Diag, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level,
     SubdiagMessageOp, Subdiagnostic,
 };
 use rustc_macros::{Diagnostic, Subdiagnostic};
@@ -1052,7 +1052,7 @@ pub(crate) struct ExpectedIdentifier {
 
 impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for ExpectedIdentifier {
     #[track_caller]
-    fn into_diag(self, dcx: &'a DiagCtxt, level: Level) -> Diag<'a, G> {
+    fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, G> {
         let token_descr = TokenDescription::from_token(&self.token);
 
         let mut diag = Diag::new(
@@ -1112,7 +1112,7 @@ pub(crate) struct ExpectedSemi {
 
 impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for ExpectedSemi {
     #[track_caller]
-    fn into_diag(self, dcx: &'a DiagCtxt, level: Level) -> Diag<'a, G> {
+    fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, G> {
         let token_descr = TokenDescription::from_token(&self.token);
 
         let mut diag = Diag::new(
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 43f4963b27a..511805cf8d6 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -7,7 +7,7 @@ use rustc_ast::ast::{self, AttrStyle};
 use rustc_ast::token::{self, CommentKind, Delimiter, IdentIsRaw, Token, TokenKind};
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::util::unicode::contains_text_flow_control_chars;
-use rustc_errors::{codes::*, Applicability, Diag, DiagCtxt, StashKey};
+use rustc_errors::{codes::*, Applicability, Diag, DiagCtxtHandle, StashKey};
 use rustc_lexer::unescape::{self, EscapeError, Mode};
 use rustc_lexer::{Base, DocStyle, RawStrError};
 use rustc_lexer::{Cursor, LiteralKind};
@@ -113,8 +113,8 @@ struct StringReader<'psess, 'src> {
 }
 
 impl<'psess, 'src> StringReader<'psess, 'src> {
-    fn dcx(&self) -> &'psess DiagCtxt {
-        &self.psess.dcx
+    fn dcx(&self) -> DiagCtxtHandle<'psess> {
+        self.psess.dcx()
     }
 
     fn mk_sp(&self, lo: BytePos, hi: BytePos) -> Span {
@@ -248,8 +248,8 @@ impl<'psess, 'src> StringReader<'psess, 'src> {
                     let suffix = if suffix_start < self.pos {
                         let string = self.str_from(suffix_start);
                         if string == "_" {
-                            self.psess
-                                .dcx
+                            self
+                                .dcx()
                                 .emit_err(errors::UnderscoreLiteralSuffix { span: self.mk_sp(suffix_start, self.pos) });
                             None
                         } else {
@@ -597,8 +597,7 @@ impl<'psess, 'src> StringReader<'psess, 'src> {
     }
 
     fn report_non_started_raw_string(&self, start: BytePos, bad_char: char) -> ! {
-        self.psess
-            .dcx
+        self.dcx()
             .struct_span_fatal(
                 self.mk_sp(start, self.pos),
                 format!(
diff --git a/compiler/rustc_parse/src/lexer/tokentrees.rs b/compiler/rustc_parse/src/lexer/tokentrees.rs
index f7645446081..8e543454691 100644
--- a/compiler/rustc_parse/src/lexer/tokentrees.rs
+++ b/compiler/rustc_parse/src/lexer/tokentrees.rs
@@ -71,7 +71,7 @@ impl<'psess, 'src> TokenTreesReader<'psess, 'src> {
 
     fn eof_err(&mut self) -> PErr<'psess> {
         let msg = "this file contains an unclosed delimiter";
-        let mut err = self.string_reader.psess.dcx.struct_span_err(self.token.span, msg);
+        let mut err = self.string_reader.dcx().struct_span_err(self.token.span, msg);
         for &(_, sp) in &self.diag_info.open_braces {
             err.span_label(sp, "unclosed delimiter");
             self.diag_info.unmatched_delims.push(UnmatchedDelim {
@@ -290,7 +290,7 @@ impl<'psess, 'src> TokenTreesReader<'psess, 'src> {
         // An unexpected closing delimiter (i.e., there is no matching opening delimiter).
         let token_str = token_to_string(&self.token);
         let msg = format!("unexpected closing delimiter: `{token_str}`");
-        let mut err = self.string_reader.psess.dcx.struct_span_err(self.token.span, msg);
+        let mut err = self.string_reader.dcx().struct_span_err(self.token.span, msg);
 
         report_suspicious_mismatch_block(
             &mut err,
diff --git a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
index cad25c66827..b7a790fcf83 100644
--- a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
+++ b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
@@ -3,7 +3,7 @@
 use std::iter::once;
 use std::ops::Range;
 
-use rustc_errors::{Applicability, DiagCtxt, ErrorGuaranteed};
+use rustc_errors::{Applicability, DiagCtxtHandle, ErrorGuaranteed};
 use rustc_lexer::unescape::{EscapeError, Mode};
 use rustc_span::{BytePos, Span};
 use tracing::debug;
@@ -11,7 +11,7 @@ use tracing::debug;
 use crate::errors::{MoreThanOneCharNote, MoreThanOneCharSugg, NoBraceUnicodeSub, UnescapeError};
 
 pub(crate) fn emit_unescape_error(
-    dcx: &DiagCtxt,
+    dcx: DiagCtxtHandle<'_>,
     // interior part of the literal, between quotes
     lit: &str,
     // full span of the literal, including quotes and any prefix
diff --git a/compiler/rustc_parse/src/lexer/unicode_chars.rs b/compiler/rustc_parse/src/lexer/unicode_chars.rs
index 8eb299108d1..0a82ede3b75 100644
--- a/compiler/rustc_parse/src/lexer/unicode_chars.rs
+++ b/compiler/rustc_parse/src/lexer/unicode_chars.rs
@@ -351,7 +351,7 @@ pub(super) fn check_for_substitution(
 
     let Some((_, ascii_name, token)) = ASCII_ARRAY.iter().find(|&&(s, _, _)| s == ascii_str) else {
         let msg = format!("substitution character not found for '{ch}'");
-        reader.psess.dcx.span_bug(span, msg);
+        reader.dcx().span_bug(span, msg);
     };
 
     // special help suggestion for "directed" double quotes
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index 25cab7252a3..5522127be83 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -73,7 +73,7 @@ pub fn new_parser_from_file<'a>(
 ) -> Result<Parser<'a>, Vec<Diag<'a>>> {
     let source_file = psess.source_map().load_file(path).unwrap_or_else(|e| {
         let msg = format!("couldn't read {}: {}", path.display(), e);
-        let mut err = psess.dcx.struct_fatal(msg);
+        let mut err = psess.dcx().struct_fatal(msg);
         if let Some(sp) = sp {
             err.span(sp);
         }
@@ -115,7 +115,7 @@ fn source_file_to_stream<'psess>(
     override_span: Option<Span>,
 ) -> Result<TokenStream, Vec<Diag<'psess>>> {
     let src = source_file.src.as_ref().unwrap_or_else(|| {
-        psess.dcx.bug(format!(
+        psess.dcx().bug(format!(
             "cannot lex `source_file` without source: {}",
             psess.source_map().filename_for_diagnostics(&source_file.name)
         ));
@@ -179,7 +179,7 @@ pub fn parse_cfg_attr(
             }
         }
         _ => {
-            psess.dcx.emit_err(errors::MalformedCfgAttr {
+            psess.dcx().emit_err(errors::MalformedCfgAttr {
                 span: attr.span,
                 sugg: CFG_ATTR_GRAMMAR_HELP,
             });
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index 62c8f9f5dac..f5c931034fd 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -41,7 +41,7 @@ impl AttrWrapper {
     }
 
     pub(crate) fn take_for_recovery(self, psess: &ParseSess) -> AttrVec {
-        psess.dcx.span_delayed_bug(
+        psess.dcx().span_delayed_bug(
             self.attrs.get(0).map(|attr| attr.span).unwrap_or(DUMMY_SP),
             "AttrVec is taken for recovery but no error is produced",
         );
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 2bb6fb53869..c1aac84bcae 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1,7 +1,6 @@
 use super::pat::Expected;
 use super::{
-    BlockMode, CommaRecoveryMode, Parser, PathStyle, Restrictions, SemiColonMode, SeqSep,
-    TokenExpectType, TokenType,
+    BlockMode, CommaRecoveryMode, Parser, PathStyle, Restrictions, SemiColonMode, SeqSep, TokenType,
 };
 use crate::errors::{
     AmbiguousPlus, AsyncMoveBlockIn2015, AttributeOnParamType, BadQPathStage2, BadTypePlus,
@@ -35,7 +34,7 @@ use rustc_ast::{
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{
-    pluralize, Applicability, Diag, DiagCtxt, ErrorGuaranteed, FatalError, PErr, PResult,
+    pluralize, Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, FatalError, PErr, PResult,
     Subdiagnostic,
 };
 use rustc_session::errors::ExprParenthesesNeeded;
@@ -241,8 +240,8 @@ impl<'a> DerefMut for SnapshotParser<'a> {
 }
 
 impl<'a> Parser<'a> {
-    pub fn dcx(&self) -> &'a DiagCtxt {
-        &self.psess.dcx
+    pub fn dcx(&self) -> DiagCtxtHandle<'a> {
+        self.psess.dcx()
     }
 
     /// Replace `self` with `snapshot.parser`.
@@ -667,7 +666,7 @@ impl<'a> Parser<'a> {
         {
             err.note("you may be trying to write a c-string literal");
             err.note("c-string literals require Rust 2021 or later");
-            err.subdiagnostic(self.dcx(), HelpUseLatestEdition::new());
+            err.subdiagnostic(HelpUseLatestEdition::new());
         }
 
         // `pub` may be used for an item or `pub(crate)`
@@ -1045,9 +1044,7 @@ impl<'a> Parser<'a> {
     /// passes through any errors encountered. Used for error recovery.
     pub(super) fn eat_to_tokens(&mut self, kets: &[&TokenKind]) {
         if let Err(err) =
-            self.parse_seq_to_before_tokens(kets, SeqSep::none(), TokenExpectType::Expect, |p| {
-                Ok(p.parse_token_tree())
-            })
+            self.parse_seq_to_before_tokens(kets, &[], SeqSep::none(), |p| Ok(p.parse_token_tree()))
         {
             err.cancel();
         }
@@ -2360,7 +2357,7 @@ impl<'a> Parser<'a> {
         let mut err = self.dcx().struct_span_err(span, msg);
         let sp = self.psess.source_map().start_point(self.token.span);
         if let Some(sp) = self.psess.ambiguous_block_expr_parse.borrow().get(&sp) {
-            err.subdiagnostic(self.dcx(), ExprParenthesesNeeded::surrounding(*sp));
+            err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
         }
         err.span_label(span, "expected expression");
 
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index e15d6ab2123..5decfc142da 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -4,7 +4,7 @@ use super::pat::{CommaRecoveryMode, Expected, RecoverColon, RecoverComma};
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{
     AttrWrapper, BlockMode, ClosureSpans, ForceCollect, Parser, PathStyle, Restrictions,
-    SemiColonMode, SeqSep, TokenExpectType, TokenType, Trailing, TrailingToken,
+    SemiColonMode, SeqSep, TokenType, Trailing, TrailingToken,
 };
 
 use crate::errors;
@@ -1461,7 +1461,7 @@ impl<'a> Parser<'a> {
                     // If the input is something like `if a { 1 } else { 2 } | if a { 3 } else { 4 }`
                     // then suggest parens around the lhs.
                     if let Some(sp) = this.psess.ambiguous_block_expr_parse.borrow().get(&lo) {
-                        err.subdiagnostic(this.dcx(), ExprParenthesesNeeded::surrounding(*sp));
+                        err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
                     }
                     err
                 })
@@ -2456,9 +2456,9 @@ impl<'a> Parser<'a> {
             self.expect(&token::BinOp(token::Or))?;
             let args = self
                 .parse_seq_to_before_tokens(
-                    &[&token::BinOp(token::Or), &token::OrOr],
+                    &[&token::BinOp(token::Or)],
+                    &[&token::OrOr],
                     SeqSep::trailing_allowed(token::Comma),
-                    TokenExpectType::NoExpect,
                     |p| p.parse_fn_block_param(),
                 )?
                 .0;
diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index 93a15c938ec..fde16ac957d 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -62,7 +62,7 @@ impl<'a> Parser<'a> {
                 let snapshot = self.create_snapshot_for_diagnostic();
                 match self.parse_ty() {
                     Ok(p) => {
-                        if let TyKind::ImplTrait(_, bounds, None) = &p.kind {
+                        if let TyKind::ImplTrait(_, bounds) = &p.kind {
                             let span = impl_span.to(self.token.span.shrink_to_lo());
                             let mut err = self.dcx().struct_span_err(
                                 span,
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 3f5a4afdad8..42f8c6e38b9 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -633,7 +633,7 @@ impl<'a> Parser<'a> {
                     // This notably includes paths passed through `ty` macro fragments (#46438).
                     TyKind::Path(None, path) => path,
                     other => {
-                        if let TyKind::ImplTrait(_, bounds, None) = other
+                        if let TyKind::ImplTrait(_, bounds) = other
                             && let [bound] = bounds.as_slice()
                         {
                             // Suggest removing extra `impl` keyword:
@@ -1966,7 +1966,7 @@ impl<'a> Parser<'a> {
         if self.token.kind == token::Not {
             if let Err(mut err) = self.unexpected() {
                 // Encounter the macro invocation
-                err.subdiagnostic(self.dcx(), MacroExpandsToAdtField { adt_ty });
+                err.subdiagnostic(MacroExpandsToAdtField { adt_ty });
                 return Err(err);
             }
         }
@@ -2382,13 +2382,10 @@ impl<'a> Parser<'a> {
                             .into_iter()
                             .any(|s| self.prev_token.is_ident_named(s));
 
-                        err.subdiagnostic(
-                            self.dcx(),
-                            errors::FnTraitMissingParen {
-                                span: self.prev_token.span,
-                                machine_applicable,
-                            },
-                        );
+                        err.subdiagnostic(errors::FnTraitMissingParen {
+                            span: self.prev_token.span,
+                            machine_applicable,
+                        });
                     }
                     return Err(err);
                 }
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index adf04fcf224..6dee913c141 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -335,18 +335,6 @@ impl TokenType {
     }
 }
 
-/// Used by [`Parser::expect_any_with_type`].
-#[derive(Copy, Clone, Debug)]
-enum TokenExpectType {
-    /// Unencountered tokens are inserted into [`Parser::expected_tokens`].
-    /// See [`Parser::check`].
-    Expect,
-
-    /// Unencountered tokens are not inserted into [`Parser::expected_tokens`].
-    /// See [`Parser::check_noexpect`].
-    NoExpect,
-}
-
 /// A sequence separator.
 #[derive(Debug)]
 struct SeqSep {
@@ -807,11 +795,13 @@ impl<'a> Parser<'a> {
     }
 
     /// Checks if the next token is contained within `kets`, and returns `true` if so.
-    fn expect_any_with_type(&mut self, kets: &[&TokenKind], expect: TokenExpectType) -> bool {
-        kets.iter().any(|k| match expect {
-            TokenExpectType::Expect => self.check(k),
-            TokenExpectType::NoExpect => self.check_noexpect(k),
-        })
+    fn expect_any_with_type(
+        &mut self,
+        kets_expected: &[&TokenKind],
+        kets_not_expected: &[&TokenKind],
+    ) -> bool {
+        kets_expected.iter().any(|k| self.check(k))
+            || kets_not_expected.iter().any(|k| self.check_noexpect(k))
     }
 
     /// Parses a sequence until the specified delimiters. The function
@@ -819,9 +809,9 @@ impl<'a> Parser<'a> {
     /// closing bracket.
     fn parse_seq_to_before_tokens<T>(
         &mut self,
-        kets: &[&TokenKind],
+        kets_expected: &[&TokenKind],
+        kets_not_expected: &[&TokenKind],
         sep: SeqSep,
-        expect: TokenExpectType,
         mut f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
     ) -> PResult<'a, (ThinVec<T>, Trailing, Recovered)> {
         let mut first = true;
@@ -829,7 +819,7 @@ impl<'a> Parser<'a> {
         let mut trailing = Trailing::No;
         let mut v = ThinVec::new();
 
-        while !self.expect_any_with_type(kets, expect) {
+        while !self.expect_any_with_type(kets_expected, kets_not_expected) {
             if let token::CloseDelim(..) | token::Eof = self.token.kind {
                 break;
             }
@@ -927,7 +917,8 @@ impl<'a> Parser<'a> {
                                     if self.token == token::Colon {
                                         // we will try to recover in `maybe_recover_struct_lit_bad_delims`
                                         return Err(expect_err);
-                                    } else if let [token::CloseDelim(Delimiter::Parenthesis)] = kets
+                                    } else if let [token::CloseDelim(Delimiter::Parenthesis)] =
+                                        kets_expected
                                     {
                                         return Err(expect_err);
                                     } else {
@@ -940,7 +931,9 @@ impl<'a> Parser<'a> {
                     }
                 }
             }
-            if sep.trailing_sep_allowed && self.expect_any_with_type(kets, expect) {
+            if sep.trailing_sep_allowed
+                && self.expect_any_with_type(kets_expected, kets_not_expected)
+            {
                 trailing = Trailing::Yes;
                 break;
             }
@@ -1020,7 +1013,7 @@ impl<'a> Parser<'a> {
         sep: SeqSep,
         f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
     ) -> PResult<'a, (ThinVec<T>, Trailing, Recovered)> {
-        self.parse_seq_to_before_tokens(&[ket], sep, TokenExpectType::Expect, f)
+        self.parse_seq_to_before_tokens(&[ket], &[], sep, f)
     }
 
     /// Parses a sequence, including only the closing delimiter. The function
@@ -1603,7 +1596,7 @@ pub(crate) fn make_unclosed_delims_error(
     if let Some(sp) = unmatched.unclosed_span {
         spans.push(sp);
     };
-    let err = psess.dcx.create_err(MismatchedClosingDelimiter {
+    let err = psess.dcx().create_err(MismatchedClosingDelimiter {
         spans,
         delimiter: pprust::token_kind_to_string(&token::CloseDelim(found_delim)).to_string(),
         unmatched: unmatched.found_span,
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 8af415f7c9d..f7f06ab7cbd 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -851,7 +851,7 @@ impl<'a> Parser<'a> {
 
         let sp = self.psess.source_map().start_point(self.token.span);
         if let Some(sp) = self.psess.ambiguous_block_expr_parse.borrow().get(&sp) {
-            err.subdiagnostic(self.dcx(), ExprParenthesesNeeded::surrounding(*sp));
+            err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
         }
 
         Err(err)
diff --git a/compiler/rustc_parse/src/parser/tests.rs b/compiler/rustc_parse/src/parser/tests.rs
index 79a6cf1b541..3a4690670af 100644
--- a/compiler/rustc_parse/src/parser/tests.rs
+++ b/compiler/rustc_parse/src/parser/tests.rs
@@ -61,7 +61,7 @@ where
 {
     let mut p = string_to_parser(&psess, s);
     let x = f(&mut p).unwrap();
-    p.psess.dcx.abort_if_errors();
+    p.dcx().abort_if_errors();
     x
 }
 
@@ -193,7 +193,7 @@ impl<T: Write> Write for Shared<T> {
 #[allow(rustc::untranslatable_diagnostic)] // no translation needed for tests
 fn test_harness(file_text: &str, span_labels: Vec<SpanLabel>, expected_output: &str) {
     create_default_session_globals_then(|| {
-        let (handler, source_map, output) = create_test_handler();
+        let (dcx, source_map, output) = create_test_handler();
         source_map.new_source_file(Path::new("test.rs").to_owned().into(), file_text.to_owned());
 
         let primary_span = make_span(&file_text, &span_labels[0].start, &span_labels[0].end);
@@ -205,7 +205,7 @@ fn test_harness(file_text: &str, span_labels: Vec<SpanLabel>, expected_output: &
             println!("text: {:?}", source_map.span_to_snippet(span));
         }
 
-        handler.span_err(msp, "foo");
+        dcx.handle().span_err(msp, "foo");
 
         assert!(
             expected_output.chars().next() == Some('\n'),
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 5bed0317e5e..fcd623b477f 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -9,7 +9,7 @@ use crate::errors::{
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 
 use rustc_ast::ptr::P;
-use rustc_ast::token::{self, Delimiter, Token, TokenKind};
+use rustc_ast::token::{self, BinOpToken, Delimiter, Token, TokenKind};
 use rustc_ast::util::case::Case;
 use rustc_ast::{
     self as ast, BareFnTy, BoundAsyncness, BoundConstness, BoundPolarity, FnRetTy, GenericBound,
@@ -316,7 +316,7 @@ impl<'a> Parser<'a> {
                             TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn)
                         }
                         (TyKind::TraitObject(bounds, _), kw::Impl) => {
-                            TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds, None)
+                            TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds)
                         }
                         _ => return Err(err),
                     };
@@ -670,33 +670,26 @@ impl<'a> Parser<'a> {
             })
         }
 
-        // parse precise captures, if any. This is `use<'lt, 'lt, P, P>`; a list of
-        // lifetimes and ident params (including SelfUpper). These are validated later
-        // for order, duplication, and whether they actually reference params.
-        let precise_capturing = if self.eat_keyword(kw::Use) {
-            let use_span = self.prev_token.span;
-            self.psess.gated_spans.gate(sym::precise_capturing, use_span);
-            let (args, args_span) = self.parse_precise_capturing_args()?;
-            Some(P((args, use_span.to(args_span))))
-        } else {
-            None
-        };
-
         // Always parse bounds greedily for better error recovery.
         let bounds = self.parse_generic_bounds()?;
 
         *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus);
 
-        Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds, precise_capturing))
+        Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds))
     }
 
     fn parse_precise_capturing_args(
         &mut self,
     ) -> PResult<'a, (ThinVec<PreciseCapturingArg>, Span)> {
         let lo = self.token.span;
-        let (args, _) = self.parse_unspanned_seq(
-            &TokenKind::Lt,
-            &TokenKind::Gt,
+        self.expect_lt()?;
+        let (args, _, _) = self.parse_seq_to_before_tokens(
+            &[&TokenKind::Gt],
+            &[
+                &TokenKind::Ge,
+                &TokenKind::BinOp(BinOpToken::Shr),
+                &TokenKind::BinOpEq(BinOpToken::Shr),
+            ],
             SeqSep::trailing_allowed(token::Comma),
             |self_| {
                 if self_.check_keyword(kw::SelfUpper) {
@@ -717,6 +710,7 @@ impl<'a> Parser<'a> {
                 }
             },
         )?;
+        self.expect_gt()?;
         Ok((args, lo.to(self.prev_token.span)))
     }
 
@@ -828,6 +822,7 @@ impl<'a> Parser<'a> {
             || self.check(&token::OpenDelim(Delimiter::Parenthesis))
             || self.check_keyword(kw::Const)
             || self.check_keyword(kw::Async)
+            || self.check_keyword(kw::Use)
     }
 
     /// Parses a bound according to the grammar:
@@ -844,6 +839,14 @@ impl<'a> Parser<'a> {
         let bound = if self.token.is_lifetime() {
             self.error_lt_bound_with_modifiers(modifiers);
             self.parse_generic_lt_bound(lo, inner_lo, has_parens)?
+        } else if self.eat_keyword(kw::Use) {
+            // parse precise captures, if any. This is `use<'lt, 'lt, P, P>`; a list of
+            // lifetimes and ident params (including SelfUpper). These are validated later
+            // for order, duplication, and whether they actually reference params.
+            let use_span = self.prev_token.span;
+            self.psess.gated_spans.gate(sym::precise_capturing, use_span);
+            let (args, args_span) = self.parse_precise_capturing_args()?;
+            GenericBound::Use(args, use_span.to(args_span))
         } else {
             self.parse_generic_ty_bound(lo, has_parens, modifiers, &leading_token)?
         };
@@ -1003,7 +1006,7 @@ impl<'a> Parser<'a> {
                             Applicability::MaybeIncorrect,
                         )
                     }
-                    TyKind::ImplTrait(_, bounds, None)
+                    TyKind::ImplTrait(_, bounds)
                         if let [GenericBound::Trait(tr, ..), ..] = bounds.as_slice() =>
                     {
                         (
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
index 19d6f512572..4ca52146039 100644
--- a/compiler/rustc_parse/src/validate_attr.rs
+++ b/compiler/rustc_parse/src/validate_attr.rs
@@ -65,7 +65,7 @@ pub fn parse_meta<'a>(psess: &'a ParseSess, attr: &Attribute) -> PResult<'a, Met
                     let res = match res {
                         Ok(lit) => {
                             if token_lit.suffix.is_some() {
-                                let mut err = psess.dcx.struct_span_err(
+                                let mut err = psess.dcx().struct_span_err(
                                     expr.span,
                                     "suffixed literals are not allowed in attributes",
                                 );
@@ -98,7 +98,7 @@ pub fn parse_meta<'a>(psess: &'a ParseSess, attr: &Attribute) -> PResult<'a, Met
                     //   the error because an earlier error will have already
                     //   been reported.
                     let msg = "attribute value must be a literal";
-                    let mut err = psess.dcx.struct_span_err(expr.span, msg);
+                    let mut err = psess.dcx().struct_span_err(expr.span, msg);
                     if let ast::ExprKind::Err(_) = expr.kind {
                         err.downgrade_to_delayed_bug();
                     }
@@ -114,7 +114,7 @@ fn check_meta_bad_delim(psess: &ParseSess, span: DelimSpan, delim: Delimiter) {
     if let Delimiter::Parenthesis = delim {
         return;
     }
-    psess.dcx.emit_err(errors::MetaBadDelim {
+    psess.dcx().emit_err(errors::MetaBadDelim {
         span: span.entire(),
         sugg: errors::MetaBadDelimSugg { open: span.open, close: span.close },
     });
@@ -124,7 +124,7 @@ pub(super) fn check_cfg_attr_bad_delim(psess: &ParseSess, span: DelimSpan, delim
     if let Delimiter::Parenthesis = delim {
         return;
     }
-    psess.dcx.emit_err(errors::CfgAttrBadDelim {
+    psess.dcx().emit_err(errors::CfgAttrBadDelim {
         span: span.entire(),
         sugg: errors::MetaBadDelimSugg { open: span.open, close: span.close },
     });
@@ -191,7 +191,7 @@ fn emit_malformed_attribute(
     } else {
         suggestions.sort();
         psess
-            .dcx
+            .dcx()
             .struct_span_err(span, error_msg)
             .with_span_suggestions(
                 span,