Auto merge of #121142 - GuillaumeGomez:rollup-5qmksjw, r=GuillaumeGomez

Rollup of 8 pull requests

Successful merges:

 - #120449 (Document requirements for unsized {Rc,Arc}::from_raw)
 - #120505 (Fix BTreeMap's Cursor::remove_{next,prev})
 - #120672 (std::thread update freebsd stack guard handling.)
 - #121088 (Implicitly enable evex512 if avx512 is enabled)
 - #121104 (Ignore unsized types when trying to determine the size of the original type)
 - #121107 (Fix msg for verbose suggestions with confusable capitalization)
 - #121113 (Continue compilation even if inherent impl checks fail)
 - #121120 (Add `ErrorGuaranteed` to `ast::LitKind::Err`, `token::LitKind::Err`.)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast/src/ast.rs

@@ -1846,7 +1846,7 @@ pub enum LitKind {
     /// A boolean literal (`true`, `false`).
     Bool(bool),
     /// Placeholder for a literal that wasn't well-formed in some way.
-    Err,
+    Err(ErrorGuaranteed),
 }
 
 impl LitKind {
@@ -1893,7 +1893,7 @@ impl LitKind {
             | LitKind::Int(_, LitIntType::Unsuffixed)
             | LitKind::Float(_, LitFloatType::Unsuffixed)
             | LitKind::Bool(..)
-            | LitKind::Err => false,
+            | LitKind::Err(_) => false,
         }
     }
 }

compiler/rustc_ast/src/token.rs

@@ -13,7 +13,7 @@ use rustc_macros::HashStable_Generic;
 use rustc_span::symbol::{kw, sym};
 #[allow(hidden_glob_reexports)]
 use rustc_span::symbol::{Ident, Symbol};
-use rustc_span::{edition::Edition, Span, DUMMY_SP};
+use rustc_span::{edition::Edition, ErrorGuaranteed, Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::fmt;
 
@@ -75,7 +75,7 @@ pub enum LitKind {
     ByteStrRaw(u8), // raw byte string delimited by `n` hash symbols
     CStr,
     CStrRaw(u8),
-    Err,
+    Err(ErrorGuaranteed),
 }
 
 /// A literal token.
@@ -144,7 +144,7 @@ impl fmt::Display for Lit {
             CStrRaw(n) => {
                 write!(f, "cr{delim}\"{symbol}\"{delim}", delim = "#".repeat(n as usize))?
             }
-            Integer | Float | Bool | Err => write!(f, "{symbol}")?,
+            Integer | Float | Bool | Err(_) => write!(f, "{symbol}")?,
         }
 
         if let Some(suffix) = suffix {
@@ -159,7 +159,7 @@ impl LitKind {
     /// An English article for the literal token kind.
     pub fn article(self) -> &'static str {
         match self {
-            Integer | Err => "an",
+            Integer | Err(_) => "an",
             _ => "a",
         }
     }
@@ -174,12 +174,12 @@ impl LitKind {
             Str | StrRaw(..) => "string",
             ByteStr | ByteStrRaw(..) => "byte string",
             CStr | CStrRaw(..) => "C string",
-            Err => "error",
+            Err(_) => "error",
         }
     }
 
     pub(crate) fn may_have_suffix(self) -> bool {
-        matches!(self, Integer | Float | Err)
+        matches!(self, Integer | Float | Err(_))
     }
 }
 

compiler/rustc_ast/src/util/literal.rs

@@ -31,20 +31,21 @@ pub fn escape_byte_str_symbol(bytes: &[u8]) -> Symbol {
 
 #[derive(Debug)]
 pub enum LitError {
-    LexerError,
+    InvalidSuffix(Symbol),
-    InvalidSuffix,
+    InvalidIntSuffix(Symbol),
-    InvalidIntSuffix,
+    InvalidFloatSuffix(Symbol),
-    InvalidFloatSuffix,
+    NonDecimalFloat(u32), // u32 is the base
-    NonDecimalFloat(u32),
+    IntTooLarge(u32),     // u32 is the base
-    IntTooLarge(u32),
 }
 
 impl LitKind {
     /// Converts literal token into a semantic literal.
     pub fn from_token_lit(lit: token::Lit) -> Result<LitKind, LitError> {
         let token::Lit { kind, symbol, suffix } = lit;
-        if suffix.is_some() && !kind.may_have_suffix() {
+        if let Some(suffix) = suffix
-            return Err(LitError::InvalidSuffix);
+            && !kind.may_have_suffix()
+        {
+            return Err(LitError::InvalidSuffix(suffix));
         }
 
         // For byte/char/string literals, chars and escapes have already been
@@ -145,7 +146,7 @@ impl LitKind {
                 buf.push(0);
                 LitKind::CStr(buf.into(), StrStyle::Raw(n))
             }
-            token::Err => LitKind::Err,
+            token::Err(guar) => LitKind::Err(guar),
         })
     }
 }
@@ -202,7 +203,7 @@ impl fmt::Display for LitKind {
                 }
             }
             LitKind::Bool(b) => write!(f, "{}", if b { "true" } else { "false" })?,
-            LitKind::Err => {
+            LitKind::Err(_) => {
                 // This only shows up in places like `-Zunpretty=hir` output, so we
                 // don't bother to produce something useful.
                 write!(f, "<bad-literal>")?;
@@ -238,7 +239,7 @@ impl MetaItemLit {
             LitKind::Char(_) => token::Char,
             LitKind::Int(..) => token::Integer,
             LitKind::Float(..) => token::Float,
-            LitKind::Err => token::Err,
+            LitKind::Err(guar) => token::Err(guar),
         };
 
         token::Lit::new(kind, self.symbol, self.suffix)
@@ -272,12 +273,12 @@ fn filtered_float_lit(
         return Err(LitError::NonDecimalFloat(base));
     }
     Ok(match suffix {
-        Some(suf) => LitKind::Float(
+        Some(suffix) => LitKind::Float(
             symbol,
-            ast::LitFloatType::Suffixed(match suf {
+            ast::LitFloatType::Suffixed(match suffix {
                 sym::f32 => ast::FloatTy::F32,
                 sym::f64 => ast::FloatTy::F64,
-                _ => return Err(LitError::InvalidFloatSuffix),
+                _ => return Err(LitError::InvalidFloatSuffix(suffix)),
             }),
         ),
         None => LitKind::Float(symbol, ast::LitFloatType::Unsuffixed),
@@ -318,17 +319,13 @@ fn integer_lit(symbol: Symbol, suffix: Option<Symbol>) -> Result<LitKind, LitErr
             // `1f64` and `2f32` etc. are valid float literals, and
             // `fxxx` looks more like an invalid float literal than invalid integer literal.
             _ if suf.as_str().starts_with('f') => return filtered_float_lit(symbol, suffix, base),
-            _ => return Err(LitError::InvalidIntSuffix),
+            _ => return Err(LitError::InvalidIntSuffix(suf)),
         },
         _ => ast::LitIntType::Unsuffixed,
     };
 
     let s = &s[if base != 10 { 2 } else { 0 }..];
-    u128::from_str_radix(s, base).map(|i| LitKind::Int(i.into(), ty)).map_err(|_| {
+    u128::from_str_radix(s, base)
-        // Small bases are lexed as if they were base 10, e.g, the string
+        .map(|i| LitKind::Int(i.into(), ty))
-        // might be `0b10201`. This will cause the conversion above to fail,
+        .map_err(|_| LitError::IntTooLarge(base))
-        // but these kinds of errors are already reported by the lexer.
-        let from_lexer = base < 10 && s.chars().any(|c| c.to_digit(10).is_some_and(|d| d >= base));
-        if from_lexer { LitError::LexerError } else { LitError::IntTooLarge(base) }
-    })
 }

compiler/rustc_ast_lowering/src/expr.rs

@@ -124,8 +124,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     let lit_kind = match LitKind::from_token_lit(*token_lit) {
                         Ok(lit_kind) => lit_kind,
                         Err(err) => {
-                            report_lit_error(&self.tcx.sess.parse_sess, err, *token_lit, e.span);
+                            let guar = report_lit_error(
-                            LitKind::Err
+                                &self.tcx.sess.parse_sess,
+                                err,
+                                *token_lit,
+                                e.span,
+                            );
+                            LitKind::Err(guar)
                         }
                     };
                     let lit = self.arena.alloc(respan(self.lower_span(e.span), lit_kind));

compiler/rustc_ast_lowering/src/lib.rs

@@ -966,10 +966,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 {
                     lit
                 } else {
+                    let guar = self.dcx().has_errors().unwrap();
                     MetaItemLit {
                         symbol: kw::Empty,
                         suffix: None,
-                        kind: LitKind::Err,
+                        kind: LitKind::Err(guar),
                         span: DUMMY_SP,
                     }
                 };

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -254,7 +254,7 @@ fn literal_to_string(lit: token::Lit) -> String {
         token::CStrRaw(n) => {
             format!("cr{delim}\"{symbol}\"{delim}", delim = "#".repeat(n as usize))
         }
-        token::Integer | token::Float | token::Bool | token::Err => symbol.to_string(),
+        token::Integer | token::Float | token::Bool | token::Err(_) => symbol.to_string(),
     };
 
     if let Some(suffix) = suffix {

compiler/rustc_builtin_macros/src/concat.rs

@@ -40,7 +40,7 @@ pub fn expand_concat(
                     cx.dcx().emit_err(errors::ConcatBytestr { span: e.span });
                     has_errors = true;
                 }
-                Ok(ast::LitKind::Err) => {
+                Ok(ast::LitKind::Err(_)) => {
                     has_errors = true;
                 }
                 Err(err) => {

compiler/rustc_builtin_macros/src/concat_bytes.rs

@@ -44,7 +44,7 @@ fn invalid_type_err(
         Ok(ast::LitKind::Bool(_)) => {
             dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "boolean", sugg: None });
         }
-        Ok(ast::LitKind::Err) => {}
+        Ok(ast::LitKind::Err(_)) => {}
         Ok(ast::LitKind::Int(_, _)) if !is_nested => {
             let sugg =
                 snippet.map(|snippet| ConcatBytesInvalidSuggestion::IntLit { span: span, snippet });

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -266,6 +266,10 @@ pub fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> LLVMFeature<'a> {
         ("riscv32" | "riscv64", "fast-unaligned-access") if get_version().0 <= 17 => {
             LLVMFeature::new("unaligned-scalar-mem")
         }
+        // For LLVM 18, enable the evex512 target feature if a avx512 target feature is enabled.
+        ("x86", s) if get_version().0 >= 18 && s.starts_with("avx512") => {
+            LLVMFeature::with_dependency(s, TargetFeatureFoldStrength::EnableOnly("evex512"))
+        }
         (_, s) => LLVMFeature::new(s),
     }
 }

compiler/rustc_errors/src/emitter.rs

@@ -1743,9 +1743,17 @@ impl HumanEmitter {
         buffer.append(0, level.to_str(), Style::Level(*level));
         buffer.append(0, ": ", Style::HeaderMsg);
 
+        let mut msg = vec![(suggestion.msg.to_owned(), Style::NoStyle)];
+        if suggestions
+            .iter()
+            .take(MAX_SUGGESTIONS)
+            .any(|(_, _, _, only_capitalization)| *only_capitalization)
+        {
+            msg.push((" (notice the capitalization difference)".into(), Style::NoStyle));
+        }
         self.msgs_to_buffer(
             &mut buffer,
-            &[(suggestion.msg.to_owned(), Style::NoStyle)],
+            &msg,
             args,
             max_line_num_len,
             "suggestion",
@@ -1754,12 +1762,8 @@ impl HumanEmitter {
 
         let mut row_num = 2;
         draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
-        let mut notice_capitalization = false;
+        for (complete, parts, highlights, _) in suggestions.iter().take(MAX_SUGGESTIONS) {
-        for (complete, parts, highlights, only_capitalization) in
-            suggestions.iter().take(MAX_SUGGESTIONS)
-        {
             debug!(?complete, ?parts, ?highlights);
-            notice_capitalization |= only_capitalization;
 
             let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
             let is_multiline = complete.lines().count() > 1;
@@ -2058,9 +2062,6 @@ impl HumanEmitter {
             let others = suggestions.len() - MAX_SUGGESTIONS;
             let msg = format!("and {} other candidate{}", others, pluralize!(others));
             buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
-        } else if notice_capitalization {
-            let msg = "notice the capitalization difference";
-            buffer.puts(row_num, max_line_num_len + 3, msg, Style::NoStyle);
         }
         emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
         Ok(())

compiler/rustc_errors/src/lib.rs

@@ -320,7 +320,9 @@ impl CodeSuggestion {
                 // We need to keep track of the difference between the existing code and the added
                 // or deleted code in order to point at the correct column *after* substitution.
                 let mut acc = 0;
+                let mut only_capitalization = false;
                 for part in &substitution.parts {
+                    only_capitalization |= is_case_difference(sm, &part.snippet, part.span);
                     let cur_lo = sm.lookup_char_pos(part.span.lo());
                     if prev_hi.line == cur_lo.line {
                         let mut count =
@@ -393,7 +395,6 @@ impl CodeSuggestion {
                     }
                 }
                 highlights.push(std::mem::take(&mut line_highlight));
-                let only_capitalization = is_case_difference(sm, &buf, bounding_span);
                 // if the replacement already ends with a newline, don't print the next line
                 if !buf.ends_with('\n') {
                     push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, None);

compiler/rustc_expand/src/base.rs

@@ -1266,7 +1266,7 @@ pub fn expr_to_spanned_string<'a>(
                 );
                 Some((err, true))
             }
-            Ok(ast::LitKind::Err) => None,
+            Ok(ast::LitKind::Err(_)) => None,
             Err(err) => {
                 report_lit_error(&cx.sess.parse_sess, err, token_lit, expr.span);
                 None

compiler/rustc_expand/src/proc_macro_server.rs

@@ -10,7 +10,7 @@ use rustc_ast::util::literal::escape_byte_str_symbol;
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
-use rustc_errors::{MultiSpan, PResult};
+use rustc_errors::{ErrorGuaranteed, MultiSpan, PResult};
 use rustc_parse::lexer::nfc_normalize;
 use rustc_parse::parse_stream_from_source_str;
 use rustc_session::parse::ParseSess;
@@ -63,7 +63,12 @@ impl FromInternal<token::LitKind> for LitKind {
             token::ByteStrRaw(n) => LitKind::ByteStrRaw(n),
             token::CStr => LitKind::CStr,
             token::CStrRaw(n) => LitKind::CStrRaw(n),
-            token::Err => LitKind::Err,
+            token::Err(_guar) => {
+                // This is the only place a `pm::bridge::LitKind::ErrWithGuar`
+                // is constructed. Note that an `ErrorGuaranteed` is available,
+                // as required. See the comment in `to_internal`.
+                LitKind::ErrWithGuar
+            }
             token::Bool => unreachable!(),
         }
     }
@@ -82,7 +87,16 @@ impl ToInternal<token::LitKind> for LitKind {
             LitKind::ByteStrRaw(n) => token::ByteStrRaw(n),
             LitKind::CStr => token::CStr,
             LitKind::CStrRaw(n) => token::CStrRaw(n),
-            LitKind::Err => token::Err,
+            LitKind::ErrWithGuar => {
+                // This is annoying but valid. `LitKind::ErrWithGuar` would
+                // have an `ErrorGuaranteed` except that type isn't available
+                // in that crate. So we have to fake one. And we don't want to
+                // use a delayed bug because there might be lots of these,
+                // which would be expensive.
+                #[allow(deprecated)]
+                let guar = ErrorGuaranteed::unchecked_error_guaranteed();
+                token::Err(guar)
+            }
         }
     }
 }
@@ -477,7 +491,7 @@ impl server::FreeFunctions for Rustc<'_, '_> {
                 | token::LitKind::ByteStrRaw(_)
                 | token::LitKind::CStr
                 | token::LitKind::CStrRaw(_)
-                | token::LitKind::Err => return Err(()),
+                | token::LitKind::Err(_) => return Err(()),
                 token::LitKind::Integer | token::LitKind::Float => {}
             }
 

compiler/rustc_hir_analysis/src/lib.rs

@@ -178,8 +178,9 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorGuaranteed> {
             let _ = tcx.ensure().coherent_trait(trait_def_id);
         }
         // these queries are executed for side-effects (error reporting):
-        res.and(tcx.ensure().crate_inherent_impls(()))
+        let _ = tcx.ensure().crate_inherent_impls(());
-            .and(tcx.ensure().crate_inherent_impls_overlap_check(()))
+        let _ = tcx.ensure().crate_inherent_impls_overlap_check(());
+        res
     })?;
 
     if tcx.features().rustc_attrs {

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1319,7 +1319,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 tcx.type_of(tcx.require_lang_item(hir::LangItem::CStr, Some(lit.span)))
                     .skip_binder(),
             ),
-            ast::LitKind::Err => Ty::new_misc_error(tcx),
+            ast::LitKind::Err(guar) => Ty::new_error(tcx, guar),
         }
     }
 

compiler/rustc_lint/src/reference_casting.rs

@@ -207,6 +207,13 @@ fn is_cast_to_bigger_memory_layout<'tcx>(
     }
 
     let from_layout = cx.layout_of(*inner_start_ty).ok()?;
+
+    // if the type isn't sized, we bail out, instead of potentially giving
+    // the user a meaningless warning.
+    if from_layout.is_unsized() {
+        return None;
+    }
+
     let alloc_layout = cx.layout_of(alloc_ty).ok()?;
     let to_layout = cx.layout_of(*inner_end_ty).ok()?;
 

compiler/rustc_mir_build/src/build/expr/as_constant.rs

@@ -164,11 +164,7 @@ fn lit_to_mir_constant<'tcx>(
             })?,
         (ast::LitKind::Bool(b), ty::Bool) => ConstValue::Scalar(Scalar::from_bool(*b)),
         (ast::LitKind::Char(c), ty::Char) => ConstValue::Scalar(Scalar::from_char(*c)),
-        (ast::LitKind::Err, _) => {
+        (ast::LitKind::Err(guar), _) => return Err(LitToConstError::Reported(*guar)),
-            return Err(LitToConstError::Reported(
-                tcx.dcx().delayed_bug("encountered LitKind::Err during mir build"),
-            ));
-        }
         _ => return Err(LitToConstError::TypeError),
     };
 

compiler/rustc_mir_build/src/thir/constant.rs

@@ -71,11 +71,7 @@ pub(crate) fn lit_to_const<'tcx>(
             ty::ValTree::from_scalar_int(bits)
         }
         (ast::LitKind::Char(c), ty::Char) => ty::ValTree::from_scalar_int((*c).into()),
-        (ast::LitKind::Err, _) => {
+        (ast::LitKind::Err(guar), _) => return Err(LitToConstError::Reported(*guar)),
-            return Err(LitToConstError::Reported(
-                tcx.dcx().delayed_bug("encountered LitKind::Err during mir build"),
-            ));
-        }
         _ => return Err(LitToConstError::TypeError),
     };
 

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -897,12 +897,14 @@ impl<'tcx> Cx<'tcx> {
                 let hir_id = self.tcx.local_def_id_to_hir_id(def_id.expect_local());
                 let generics = self.tcx.generics_of(hir_id.owner);
                 let Some(&index) = generics.param_def_id_to_index.get(&def_id) else {
-                    self.tcx.dcx().has_errors().unwrap();
+                    let guar = self.tcx.dcx().has_errors().unwrap();
                     // We already errored about a late bound const
-                    return ExprKind::Literal {
+
-                        lit: &Spanned { span: DUMMY_SP, node: LitKind::Err },
+                    let lit = self
-                        neg: false,
+                        .tcx
-                    };
+                        .hir_arena
+                        .alloc(Spanned { span: DUMMY_SP, node: LitKind::Err(guar) });
+                    return ExprKind::Literal { lit, neg: false };
                 };
                 let name = self.tcx.hir().name(hir_id);
                 let param = ty::ParamConst::new(index, name);

compiler/rustc_parse/src/lexer/mod.rs

@@ -16,7 +16,7 @@ use rustc_session::lint::builtin::{
 };
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::ParseSess;
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::Symbol;
 use rustc_span::{edition::Edition, BytePos, Pos, Span};
 
 mod diagnostics;
@@ -478,26 +478,27 @@ impl<'sess, 'src> StringReader<'sess, 'src> {
                 }
             }
             rustc_lexer::LiteralKind::Int { base, empty_int } => {
+                let mut kind = token::Integer;
                 if empty_int {
                     let span = self.mk_sp(start, end);
-                    self.dcx().emit_err(errors::NoDigitsLiteral { span });
+                    let guar = self.dcx().emit_err(errors::NoDigitsLiteral { span });
-                    (token::Integer, sym::integer(0))
+                    kind = token::Err(guar);
-                } else {
+                } else if matches!(base, Base::Binary | Base::Octal) {
-                    if matches!(base, Base::Binary | Base::Octal) {
+                    let base = base as u32;
-                        let base = base as u32;
+                    let s = self.str_from_to(start + BytePos(2), end);
-                        let s = self.str_from_to(start + BytePos(2), end);
+                    for (idx, c) in s.char_indices() {
-                        for (idx, c) in s.char_indices() {
+                        let span = self.mk_sp(
-                            let span = self.mk_sp(
+                            start + BytePos::from_usize(2 + idx),
-                                start + BytePos::from_usize(2 + idx),
+                            start + BytePos::from_usize(2 + idx + c.len_utf8()),
-                                start + BytePos::from_usize(2 + idx + c.len_utf8()),
+                        );
-                            );
+                        if c != '_' && c.to_digit(base).is_none() {
-                            if c != '_' && c.to_digit(base).is_none() {
+                            let guar =
                                 self.dcx().emit_err(errors::InvalidDigitLiteral { span, base });
-                            }
+                            kind = token::Err(guar);
                         }
                     }
-                    (token::Integer, self.symbol_from_to(start, end))
                 }
+                (kind, self.symbol_from_to(start, end))
             }
             rustc_lexer::LiteralKind::Float { base, empty_exponent } => {
                 if empty_exponent {
@@ -691,7 +692,7 @@ impl<'sess, 'src> StringReader<'sess, 'src> {
 
     fn cook_common(
         &self,
-        kind: token::LitKind,
+        mut kind: token::LitKind,
         mode: Mode,
         start: BytePos,
         end: BytePos,
@@ -699,7 +700,6 @@ impl<'sess, 'src> StringReader<'sess, 'src> {
         postfix_len: u32,
         unescape: fn(&str, Mode, &mut dyn FnMut(Range<usize>, Result<(), EscapeError>)),
     ) -> (token::LitKind, Symbol) {
-        let mut has_fatal_err = false;
         let content_start = start + BytePos(prefix_len);
         let content_end = end - BytePos(postfix_len);
         let lit_content = self.str_from_to(content_start, content_end);
@@ -711,10 +711,8 @@ impl<'sess, 'src> StringReader<'sess, 'src> {
                 let lo = content_start + BytePos(start);
                 let hi = lo + BytePos(end - start);
                 let span = self.mk_sp(lo, hi);
-                if err.is_fatal() {
+                let is_fatal = err.is_fatal();
-                    has_fatal_err = true;
+                if let Some(guar) = emit_unescape_error(
-                }
-                emit_unescape_error(
                     self.dcx(),
                     lit_content,
                     span_with_quotes,
@@ -722,17 +720,21 @@ impl<'sess, 'src> StringReader<'sess, 'src> {
                     mode,
                     range,
                     err,
-                );
+                ) {
+                    assert!(is_fatal);
+                    kind = token::Err(guar);
+                }
             }
         });
 
         // We normally exclude the quotes for the symbol, but for errors we
         // include it because it results in clearer error messages.
-        if !has_fatal_err {
+        let sym = if !matches!(kind, token::Err(_)) {
-            (kind, Symbol::intern(lit_content))
+            Symbol::intern(lit_content)
         } else {
-            (token::Err, self.symbol_from_to(start, end))
+            self.symbol_from_to(start, end)
-        }
+        };
+        (kind, sym)
     }
 
     fn cook_unicode(

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};
+use rustc_errors::{Applicability, DiagCtxt, ErrorGuaranteed};
 use rustc_lexer::unescape::{EscapeError, Mode};
 use rustc_span::{BytePos, Span};
 
@@ -21,7 +21,7 @@ pub(crate) fn emit_unescape_error(
     // range of the error inside `lit`
     range: Range<usize>,
     error: EscapeError,
-) {
+) -> Option<ErrorGuaranteed> {
     debug!(
         "emit_unescape_error: {:?}, {:?}, {:?}, {:?}, {:?}",
         lit, full_lit_span, mode, range, error
@@ -31,12 +31,12 @@ pub(crate) fn emit_unescape_error(
         let span = err_span.with_lo(err_span.hi() - BytePos(c.len_utf8() as u32));
         (c, span)
     };
-    match error {
+    Some(match error {
         EscapeError::LoneSurrogateUnicodeEscape => {
-            dcx.emit_err(UnescapeError::InvalidUnicodeEscape { span: err_span, surrogate: true });
+            dcx.emit_err(UnescapeError::InvalidUnicodeEscape { span: err_span, surrogate: true })
         }
         EscapeError::OutOfRangeUnicodeEscape => {
-            dcx.emit_err(UnescapeError::InvalidUnicodeEscape { span: err_span, surrogate: false });
+            dcx.emit_err(UnescapeError::InvalidUnicodeEscape { span: err_span, surrogate: false })
         }
         EscapeError::MoreThanOneChar => {
             use unicode_normalization::{char::is_combining_mark, UnicodeNormalization};
@@ -106,7 +106,7 @@ pub(crate) fn emit_unescape_error(
                 span: full_lit_span,
                 note,
                 suggestion: sugg,
-            });
+            })
         }
         EscapeError::EscapeOnlyChar => {
             let (c, char_span) = last_char();
@@ -116,15 +116,15 @@ pub(crate) fn emit_unescape_error(
                 escaped_sugg: c.escape_default().to_string(),
                 escaped_msg: escaped_char(c),
                 byte: mode == Mode::Byte,
-            });
+            })
         }
         EscapeError::BareCarriageReturn => {
             let double_quotes = mode.in_double_quotes();
-            dcx.emit_err(UnescapeError::BareCr { span: err_span, double_quotes });
+            dcx.emit_err(UnescapeError::BareCr { span: err_span, double_quotes })
         }
         EscapeError::BareCarriageReturnInRawString => {
             assert!(mode.in_double_quotes());
-            dcx.emit_err(UnescapeError::BareCrRawString(err_span));
+            dcx.emit_err(UnescapeError::BareCrRawString(err_span))
         }
         EscapeError::InvalidEscape => {
             let (c, span) = last_char();
@@ -161,16 +161,14 @@ pub(crate) fn emit_unescape_error(
                      <https://doc.rust-lang.org/reference/tokens.html#literals>",
                 );
             }
-            diag.emit();
+            diag.emit()
-        }
-        EscapeError::TooShortHexEscape => {
-            dcx.emit_err(UnescapeError::TooShortHexEscape(err_span));
         }
+        EscapeError::TooShortHexEscape => dcx.emit_err(UnescapeError::TooShortHexEscape(err_span)),
         EscapeError::InvalidCharInHexEscape | EscapeError::InvalidCharInUnicodeEscape => {
             let (c, span) = last_char();
             let is_hex = error == EscapeError::InvalidCharInHexEscape;
             let ch = escaped_char(c);
-            dcx.emit_err(UnescapeError::InvalidCharInEscape { span, is_hex, ch });
+            dcx.emit_err(UnescapeError::InvalidCharInEscape { span, is_hex, ch })
         }
         EscapeError::NonAsciiCharInByte => {
             let (c, span) = last_char();
@@ -213,23 +211,23 @@ pub(crate) fn emit_unescape_error(
                     Applicability::MaybeIncorrect,
                 );
             }
-            err.emit();
+            err.emit()
         }
         EscapeError::OutOfRangeHexEscape => {
-            dcx.emit_err(UnescapeError::OutOfRangeHexEscape(err_span));
+            dcx.emit_err(UnescapeError::OutOfRangeHexEscape(err_span))
         }
         EscapeError::LeadingUnderscoreUnicodeEscape => {
             let (c, span) = last_char();
             dcx.emit_err(UnescapeError::LeadingUnderscoreUnicodeEscape {
                 span,
                 ch: escaped_char(c),
-            });
+            })
         }
         EscapeError::OverlongUnicodeEscape => {
-            dcx.emit_err(UnescapeError::OverlongUnicodeEscape(err_span));
+            dcx.emit_err(UnescapeError::OverlongUnicodeEscape(err_span))
         }
         EscapeError::UnclosedUnicodeEscape => {
-            dcx.emit_err(UnescapeError::UnclosedUnicodeEscape(err_span, err_span.shrink_to_hi()));
+            dcx.emit_err(UnescapeError::UnclosedUnicodeEscape(err_span, err_span.shrink_to_hi()))
         }
         EscapeError::NoBraceInUnicodeEscape => {
             let mut suggestion = "\\u{".to_owned();
@@ -248,23 +246,17 @@ pub(crate) fn emit_unescape_error(
             } else {
                 (Some(err_span), NoBraceUnicodeSub::Help)
             };
-            dcx.emit_err(UnescapeError::NoBraceInUnicodeEscape { span: err_span, label, sub });
+            dcx.emit_err(UnescapeError::NoBraceInUnicodeEscape { span: err_span, label, sub })
         }
         EscapeError::UnicodeEscapeInByte => {
-            dcx.emit_err(UnescapeError::UnicodeEscapeInByte(err_span));
+            dcx.emit_err(UnescapeError::UnicodeEscapeInByte(err_span))
         }
         EscapeError::EmptyUnicodeEscape => {
-            dcx.emit_err(UnescapeError::EmptyUnicodeEscape(err_span));
+            dcx.emit_err(UnescapeError::EmptyUnicodeEscape(err_span))
-        }
-        EscapeError::ZeroChars => {
-            dcx.emit_err(UnescapeError::ZeroChars(err_span));
-        }
-        EscapeError::LoneSlash => {
-            dcx.emit_err(UnescapeError::LoneSlash(err_span));
-        }
-        EscapeError::NulInCStr => {
-            dcx.emit_err(UnescapeError::NulInCStr { span: err_span });
         }
+        EscapeError::ZeroChars => dcx.emit_err(UnescapeError::ZeroChars(err_span)),
+        EscapeError::LoneSlash => dcx.emit_err(UnescapeError::LoneSlash(err_span)),
+        EscapeError::NulInCStr => dcx.emit_err(UnescapeError::NulInCStr { span: err_span }),
         EscapeError::UnskippedWhitespaceWarning => {
             let (c, char_span) = last_char();
             dcx.emit_warn(UnescapeError::UnskippedWhitespace {
@@ -272,11 +264,13 @@ pub(crate) fn emit_unescape_error(
                 ch: escaped_char(c),
                 char_span,
             });
+            return None;
         }
         EscapeError::MultipleSkippedLinesWarning => {
             dcx.emit_warn(UnescapeError::MultipleSkippedLinesWarning(err_span));
+            return None;
         }
-    }
+    })
 }
 
 /// Pushes a character to a message string for error reporting

compiler/rustc_parse/src/parser/expr.rs

@@ -2140,12 +2140,12 @@ impl<'a> Parser<'a> {
                     Err(err) => {
                         let span = token.uninterpolated_span();
                         self.bump();
-                        report_lit_error(self.sess, err, lit, span);
+                        let guar = report_lit_error(self.sess, err, lit, span);
                         // Pack possible quotes and prefixes from the original literal into
                         // the error literal's symbol so they can be pretty-printed faithfully.
                         let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None);
                         let symbol = Symbol::intern(&suffixless_lit.to_string());
-                        let lit = token::Lit::new(token::Err, symbol, lit.suffix);
+                        let lit = token::Lit::new(token::Err(guar), symbol, lit.suffix);
                         Some(
                             MetaItemLit::from_token_lit(lit, span)
                                 .unwrap_or_else(|_| unreachable!()),

compiler/rustc_parse/src/parser/mod.rs

@@ -1459,7 +1459,7 @@ impl<'a> Parser<'a> {
         match self.parse_str_lit() {
             Ok(str_lit) => Some(str_lit),
             Err(Some(lit)) => match lit.kind {
-                ast::LitKind::Err => None,
+                ast::LitKind::Err(_) => None,
                 _ => {
                     self.dcx().emit_err(NonStringAbiLiteral { span: lit.span });
                     None

compiler/rustc_parse/src/validate_attr.rs

@@ -70,11 +70,11 @@ pub fn parse_meta<'a>(sess: &'a ParseSess, attr: &Attribute) -> PResult<'a, Meta
                             }
                         }
                         Err(err) => {
-                            report_lit_error(sess, err, token_lit, expr.span);
+                            let guar = report_lit_error(sess, err, token_lit, expr.span);
                             let lit = ast::MetaItemLit {
                                 symbol: token_lit.symbol,
                                 suffix: token_lit.suffix,
-                                kind: ast::LitKind::Err,
+                                kind: ast::LitKind::Err(guar),
                                 span: expr.span,
                             };
                             MetaItemKind::NameValue(lit)

compiler/rustc_session/src/errors.rs

@@ -3,7 +3,8 @@ use std::num::NonZeroU32;
 use rustc_ast::token;
 use rustc_ast::util::literal::LitError;
 use rustc_errors::{
-    codes::*, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, IntoDiagnostic, Level, MultiSpan,
+    codes::*, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, IntoDiagnostic,
+    Level, MultiSpan,
 };
 use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
@@ -344,7 +345,12 @@ pub(crate) struct BinaryFloatLiteralNotSupported {
     pub span: Span,
 }
 
-pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span: Span) {
+pub fn report_lit_error(
+    sess: &ParseSess,
+    err: LitError,
+    lit: token::Lit,
+    span: Span,
+) -> ErrorGuaranteed {
     // Checks if `s` looks like i32 or u1234 etc.
     fn looks_like_width_suffix(first_chars: &[char], s: &str) -> bool {
         s.len() > 1 && s.starts_with(first_chars) && s[1..].chars().all(|c| c.is_ascii_digit())
@@ -372,47 +378,37 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
         valid.then(|| format!("0{}{}", base_char.to_ascii_lowercase(), &suffix[1..]))
     }
 
-    let token::Lit { kind, symbol, suffix, .. } = lit;
     let dcx = &sess.dcx;
     match err {
-        // `LexerError` is an error, but it was already reported
+        LitError::InvalidSuffix(suffix) => {
-        // by lexer, so here we don't report it the second time.
+            dcx.emit_err(InvalidLiteralSuffix { span, kind: lit.kind.descr(), suffix })
-        LitError::LexerError => {}
-        LitError::InvalidSuffix => {
-            if let Some(suffix) = suffix {
-                dcx.emit_err(InvalidLiteralSuffix { span, kind: kind.descr(), suffix });
-            }
         }
-        LitError::InvalidIntSuffix => {
+        LitError::InvalidIntSuffix(suffix) => {
-            let suf = suffix.expect("suffix error with no suffix");
+            let suf = suffix.as_str();
-            let suf = suf.as_str();
             if looks_like_width_suffix(&['i', 'u'], suf) {
                 // If it looks like a width, try to be helpful.
-                dcx.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() });
+                dcx.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() })
-            } else if let Some(fixed) = fix_base_capitalisation(symbol.as_str(), suf) {
+            } else if let Some(fixed) = fix_base_capitalisation(lit.symbol.as_str(), suf) {
-                dcx.emit_err(InvalidNumLiteralBasePrefix { span, fixed });
+                dcx.emit_err(InvalidNumLiteralBasePrefix { span, fixed })
             } else {
-                dcx.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() });
+                dcx.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() })
             }
         }
-        LitError::InvalidFloatSuffix => {
+        LitError::InvalidFloatSuffix(suffix) => {
-            let suf = suffix.expect("suffix error with no suffix");
+            let suf = suffix.as_str();
-            let suf = suf.as_str();
             if looks_like_width_suffix(&['f'], suf) {
                 // If it looks like a width, try to be helpful.
-                dcx.emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() });
+                dcx.emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() })
             } else {
-                dcx.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() });
+                dcx.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() })
             }
         }
-        LitError::NonDecimalFloat(base) => {
+        LitError::NonDecimalFloat(base) => match base {
-            match base {
+            16 => dcx.emit_err(HexadecimalFloatLiteralNotSupported { span }),
-                16 => dcx.emit_err(HexadecimalFloatLiteralNotSupported { span }),
+            8 => dcx.emit_err(OctalFloatLiteralNotSupported { span }),
-                8 => dcx.emit_err(OctalFloatLiteralNotSupported { span }),
+            2 => dcx.emit_err(BinaryFloatLiteralNotSupported { span }),
-                2 => dcx.emit_err(BinaryFloatLiteralNotSupported { span }),
+            _ => unreachable!(),
-                _ => unreachable!(),
+        },
-            };
-        }
         LitError::IntTooLarge(base) => {
             let max = u128::MAX;
             let limit = match base {
@@ -421,7 +417,7 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
                 16 => format!("{max:#x}"),
                 _ => format!("{max}"),
             };
-            dcx.emit_err(IntLiteralTooLarge { span, limit });
+            dcx.emit_err(IntLiteralTooLarge { span, limit })
         }
     }
 }

library/alloc/src/collections/btree/map.rs

@@ -3247,9 +3247,15 @@ impl<'a, K: Ord, V, A: Allocator + Clone> CursorMutKey<'a, K, V, A> {
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn remove_next(&mut self) -> Option<(K, V)> {
         let current = self.current.take()?;
+        if current.reborrow().next_kv().is_err() {
+            self.current = Some(current);
+            return None;
+        }
         let mut emptied_internal_root = false;
         let (kv, pos) = current
             .next_kv()
+            // This should be unwrap(), but that doesn't work because NodeRef
+            // doesn't implement Debug. The condition is checked above.
             .ok()?
             .remove_kv_tracking(|| emptied_internal_root = true, self.alloc.clone());
         self.current = Some(pos);
@@ -3270,9 +3276,15 @@ impl<'a, K: Ord, V, A: Allocator + Clone> CursorMutKey<'a, K, V, A> {
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn remove_prev(&mut self) -> Option<(K, V)> {
         let current = self.current.take()?;
+        if current.reborrow().next_back_kv().is_err() {
+            self.current = Some(current);
+            return None;
+        }
         let mut emptied_internal_root = false;
         let (kv, pos) = current
             .next_back_kv()
+            // This should be unwrap(), but that doesn't work because NodeRef
+            // doesn't implement Debug. The condition is checked above.
             .ok()?
             .remove_kv_tracking(|| emptied_internal_root = true, self.alloc.clone());
         self.current = Some(pos);

library/alloc/src/rc.rs

@@ -1184,12 +1184,19 @@ impl<T: ?Sized> Rc<T> {
     /// Constructs an `Rc<T>` from a raw pointer.
     ///
     /// The raw pointer must have been previously returned by a call to
-    /// [`Rc<U>::into_raw`][into_raw] where `U` must have the same size
+    /// [`Rc<U>::into_raw`][into_raw] with the following requirements:
-    /// and alignment as `T`. This is trivially true if `U` is `T`.
+    ///
-    /// Note that if `U` is not `T` but has the same size and alignment, this is
+    /// * If `U` is sized, it must have the same size and alignment as `T`. This
-    /// basically like transmuting references of different types. See
+    ///   is trivially true if `U` is `T`.
-    /// [`mem::transmute`][transmute] for more information on what
+    /// * If `U` is unsized, its data pointer must have the same size and
-    /// restrictions apply in this case.
+    ///   alignment as `T`. This is trivially true if `Rc<U>` was constructed
+    ///   through `Rc<T>` and then converted to `Rc<U>` through an [unsized
+    ///   coercion].
+    ///
+    /// Note that if `U` or `U`'s data pointer is not `T` but has the same size
+    /// and alignment, this is basically like transmuting references of
+    /// different types. See [`mem::transmute`][transmute] for more information
+    /// on what restrictions apply in this case.
     ///
     /// The raw pointer must point to a block of memory allocated by the global allocator
     ///
@@ -1201,6 +1208,7 @@ impl<T: ?Sized> Rc<T> {
     ///
     /// [into_raw]: Rc::into_raw
     /// [transmute]: core::mem::transmute
+    /// [unsized coercion]: https://doc.rust-lang.org/reference/type-coercions.html#unsized-coercions
     ///
     /// # Examples
     ///
@@ -1220,6 +1228,20 @@ impl<T: ?Sized> Rc<T> {
     ///
     /// // The memory was freed when `x` went out of scope above, so `x_ptr` is now dangling!
     /// ```
+    ///
+    /// Convert a slice back into its original array:
+    ///
+    /// ```
+    /// use std::rc::Rc;
+    ///
+    /// let x: Rc<[u32]> = Rc::new([1, 2, 3]);
+    /// let x_ptr: *const [u32] = Rc::into_raw(x);
+    ///
+    /// unsafe {
+    ///     let x: Rc<[u32; 3]> = Rc::from_raw(x_ptr.cast::<[u32; 3]>());
+    ///     assert_eq!(&*x, &[1, 2, 3]);
+    /// }
+    /// ```
     #[inline]
     #[stable(feature = "rc_raw", since = "1.17.0")]
     pub unsafe fn from_raw(ptr: *const T) -> Self {
@@ -1344,13 +1366,20 @@ impl<T: ?Sized, A: Allocator> Rc<T, A> {
 
     /// Constructs an `Rc<T, A>` from a raw pointer in the provided allocator.
     ///
-    /// The raw pointer must have been previously returned by a call to
+    /// The raw pointer must have been previously returned by a call to [`Rc<U,
-    /// [`Rc<U, A>::into_raw`][into_raw] where `U` must have the same size
+    /// A>::into_raw`][into_raw] with the following requirements:
-    /// and alignment as `T`. This is trivially true if `U` is `T`.
+    ///
-    /// Note that if `U` is not `T` but has the same size and alignment, this is
+    /// * If `U` is sized, it must have the same size and alignment as `T`. This
-    /// basically like transmuting references of different types. See
+    ///   is trivially true if `U` is `T`.
-    /// [`mem::transmute`] for more information on what
+    /// * If `U` is unsized, its data pointer must have the same size and
-    /// restrictions apply in this case.
+    ///   alignment as `T`. This is trivially true if `Rc<U>` was constructed
+    ///   through `Rc<T>` and then converted to `Rc<U>` through an [unsized
+    ///   coercion].
+    ///
+    /// Note that if `U` or `U`'s data pointer is not `T` but has the same size
+    /// and alignment, this is basically like transmuting references of
+    /// different types. See [`mem::transmute`][transmute] for more information
+    /// on what restrictions apply in this case.
     ///
     /// The raw pointer must point to a block of memory allocated by `alloc`
     ///
@@ -1361,6 +1390,8 @@ impl<T: ?Sized, A: Allocator> Rc<T, A> {
     /// even if the returned `Rc<T>` is never accessed.
     ///
     /// [into_raw]: Rc::into_raw
+    /// [transmute]: core::mem::transmute
+    /// [unsized coercion]: https://doc.rust-lang.org/reference/type-coercions.html#unsized-coercions
     ///
     /// # Examples
     ///
@@ -1383,6 +1414,23 @@ impl<T: ?Sized, A: Allocator> Rc<T, A> {
     ///
     /// // The memory was freed when `x` went out of scope above, so `x_ptr` is now dangling!
     /// ```
+    ///
+    /// Convert a slice back into its original array:
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::rc::Rc;
+    /// use std::alloc::System;
+    ///
+    /// let x: Rc<[u32], _> = Rc::new_in([1, 2, 3], System);
+    /// let x_ptr: *const [u32] = Rc::into_raw(x);
+    ///
+    /// unsafe {
+    ///     let x: Rc<[u32; 3], _> = Rc::from_raw_in(x_ptr.cast::<[u32; 3]>(), System);
+    ///     assert_eq!(&*x, &[1, 2, 3]);
+    /// }
+    /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
     pub unsafe fn from_raw_in(ptr: *const T, alloc: A) -> Self {
         let offset = unsafe { data_offset(ptr) };

library/alloc/src/sync.rs

@@ -1333,12 +1333,19 @@ impl<T: ?Sized> Arc<T> {
     /// Constructs an `Arc<T>` from a raw pointer.
     ///
     /// The raw pointer must have been previously returned by a call to
-    /// [`Arc<U>::into_raw`][into_raw] where `U` must have the same size and
+    /// [`Arc<U>::into_raw`][into_raw] with the following requirements:
-    /// alignment as `T`. This is trivially true if `U` is `T`.
+    ///
-    /// Note that if `U` is not `T` but has the same size and alignment, this is
+    /// * If `U` is sized, it must have the same size and alignment as `T`. This
-    /// basically like transmuting references of different types. See
+    ///   is trivially true if `U` is `T`.
-    /// [`mem::transmute`][transmute] for more information on what
+    /// * If `U` is unsized, its data pointer must have the same size and
-    /// restrictions apply in this case.
+    ///   alignment as `T`. This is trivially true if `Arc<U>` was constructed
+    ///   through `Arc<T>` and then converted to `Arc<U>` through an [unsized
+    ///   coercion].
+    ///
+    /// Note that if `U` or `U`'s data pointer is not `T` but has the same size
+    /// and alignment, this is basically like transmuting references of
+    /// different types. See [`mem::transmute`][transmute] for more information
+    /// on what restrictions apply in this case.
     ///
     /// The user of `from_raw` has to make sure a specific value of `T` is only
     /// dropped once.
@@ -1348,6 +1355,7 @@ impl<T: ?Sized> Arc<T> {
     ///
     /// [into_raw]: Arc::into_raw
     /// [transmute]: core::mem::transmute
+    /// [unsized coercion]: https://doc.rust-lang.org/reference/type-coercions.html#unsized-coercions
     ///
     /// # Examples
     ///
@@ -1367,6 +1375,20 @@ impl<T: ?Sized> Arc<T> {
     ///
     /// // The memory was freed when `x` went out of scope above, so `x_ptr` is now dangling!
     /// ```
+    ///
+    /// Convert a slice back into its original array:
+    ///
+    /// ```
+    /// use std::sync::Arc;
+    ///
+    /// let x: Arc<[u32]> = Arc::new([1, 2, 3]);
+    /// let x_ptr: *const [u32] = Arc::into_raw(x);
+    ///
+    /// unsafe {
+    ///     let x: Arc<[u32; 3]> = Arc::from_raw(x_ptr.cast::<[u32; 3]>());
+    ///     assert_eq!(&*x, &[1, 2, 3]);
+    /// }
+    /// ```
     #[inline]
     #[stable(feature = "rc_raw", since = "1.17.0")]
     pub unsafe fn from_raw(ptr: *const T) -> Self {
@@ -1496,13 +1518,20 @@ impl<T: ?Sized, A: Allocator> Arc<T, A> {
 
     /// Constructs an `Arc<T, A>` from a raw pointer.
     ///
-    /// The raw pointer must have been previously returned by a call to
+    /// The raw pointer must have been previously returned by a call to [`Arc<U,
-    /// [`Arc<U, A>::into_raw`][into_raw] where `U` must have the same size and
+    /// A>::into_raw`][into_raw] with the following requirements:
-    /// alignment as `T`. This is trivially true if `U` is `T`.
+    ///
-    /// Note that if `U` is not `T` but has the same size and alignment, this is
+    /// * If `U` is sized, it must have the same size and alignment as `T`. This
-    /// basically like transmuting references of different types. See
+    ///   is trivially true if `U` is `T`.
-    /// [`mem::transmute`] for more information on what
+    /// * If `U` is unsized, its data pointer must have the same size and
-    /// restrictions apply in this case.
+    ///   alignment as `T`. This is trivially true if `Arc<U>` was constructed
+    ///   through `Arc<T>` and then converted to `Arc<U>` through an [unsized
+    ///   coercion].
+    ///
+    /// Note that if `U` or `U`'s data pointer is not `T` but has the same size
+    /// and alignment, this is basically like transmuting references of
+    /// different types. See [`mem::transmute`][transmute] for more information
+    /// on what restrictions apply in this case.
     ///
     /// The raw pointer must point to a block of memory allocated by `alloc`
     ///
@@ -1513,6 +1542,8 @@ impl<T: ?Sized, A: Allocator> Arc<T, A> {
     /// even if the returned `Arc<T>` is never accessed.
     ///
     /// [into_raw]: Arc::into_raw
+    /// [transmute]: core::mem::transmute
+    /// [unsized coercion]: https://doc.rust-lang.org/reference/type-coercions.html#unsized-coercions
     ///
     /// # Examples
     ///
@@ -1535,6 +1566,23 @@ impl<T: ?Sized, A: Allocator> Arc<T, A> {
     ///
     /// // The memory was freed when `x` went out of scope above, so `x_ptr` is now dangling!
     /// ```
+    ///
+    /// Convert a slice back into its original array:
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::sync::Arc;
+    /// use std::alloc::System;
+    ///
+    /// let x: Arc<[u32], _> = Arc::new_in([1, 2, 3], System);
+    /// let x_ptr: *const [u32] = Arc::into_raw(x);
+    ///
+    /// unsafe {
+    ///     let x: Arc<[u32; 3], _> = Arc::from_raw_in(x_ptr.cast::<[u32; 3]>(), System);
+    ///     assert_eq!(&*x, &[1, 2, 3]);
+    /// }
+    /// ```
     #[inline]
     #[unstable(feature = "allocator_api", issue = "32838")]
     pub unsafe fn from_raw_in(ptr: *const T, alloc: A) -> Self {

library/proc_macro/src/bridge/mod.rs

@@ -337,7 +337,11 @@ pub enum LitKind {
     ByteStrRaw(u8),
     CStr,
     CStrRaw(u8),
-    Err,
+    // This should have an `ErrorGuaranteed`, except that type isn't available
+    // in this crate. (Imagine it is there.) Hence the `WithGuar` suffix. Must
+    // only be constructed in `LitKind::from_internal`, where an
+    // `ErrorGuaranteed` is available.
+    ErrWithGuar,
 }
 
 rpc_encode_decode!(
@@ -352,7 +356,7 @@ rpc_encode_decode!(
         ByteStrRaw(n),
         CStr,
         CStrRaw(n),
-        Err,
+        ErrWithGuar,
     }
 );
 

library/proc_macro/src/lib.rs

@@ -1451,7 +1451,7 @@ impl Literal {
                 f(&["cr", hashes, "\"", symbol, "\"", hashes, suffix])
             }
 
-            bridge::LitKind::Integer | bridge::LitKind::Float | bridge::LitKind::Err => {
+            bridge::LitKind::Integer | bridge::LitKind::Float | bridge::LitKind::ErrWithGuar => {
                 f(&[symbol, suffix])
             }
         })

library/std/src/sys/pal/unix/thread.rs

@@ -847,11 +847,31 @@ pub mod guard {
             let stackptr = get_stack_start_aligned()?;
             let guardaddr = stackptr.addr();
             // Technically the number of guard pages is tunable and controlled
-            // by the security.bsd.stack_guard_page sysctl, but there are
+            // by the security.bsd.stack_guard_page sysctl.
-            // few reasons to change it from the default. The default value has
+            // By default it is 1, checking once is enough since it is
-            // been 1 ever since FreeBSD 11.1 and 10.4.
+            // a boot time config value.
-            const GUARD_PAGES: usize = 1;
+            static LOCK: crate::sync::OnceLock<usize> = crate::sync::OnceLock::new();
-            let guard = guardaddr..guardaddr + GUARD_PAGES * page_size;
+            let guard = guardaddr
+                ..guardaddr
+                    + *LOCK.get_or_init(|| {
+                        use crate::sys::weak::dlsym;
+                        dlsym!(fn sysctlbyname(*const libc::c_char, *mut libc::c_void, *mut libc::size_t, *const libc::c_void, libc::size_t) -> libc::c_int);
+                        let mut guard: usize = 0;
+                        let mut size = crate::mem::size_of_val(&guard);
+                        let oid = crate::ffi::CStr::from_bytes_with_nul(
+                            b"security.bsd.stack_guard_page\0",
+                        )
+                        .unwrap();
+                        match sysctlbyname.get() {
+                            Some(fcn) => {
+                                if fcn(oid.as_ptr(), &mut guard as *mut _ as *mut _, &mut size as *mut _ as *mut _, crate::ptr::null_mut(), 0) == 0 {
+                                    return guard;
+                                }
+                                return 1;
+                            },
+                            _ => { return 1; }
+                        }
+                    }) * page_size;
             Some(guard)
         } else if cfg!(target_os = "openbsd") {
             // OpenBSD stack already includes a guard page, and stack is

src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs

@@ -295,7 +295,8 @@ impl<'a> NormalizedPat<'a> {
                     LitKind::Char(val) => Self::LitInt(val.into()),
                     LitKind::Int(val, _) => Self::LitInt(val.get()),
                     LitKind::Bool(val) => Self::LitBool(val),
-                    LitKind::Float(..) | LitKind::Err => Self::Wild,
+                    LitKind::Float(..) => Self::Wild,
+                    LitKind::Err(guar) => Self::Err(guar),
                 },
                 _ => Self::Wild,
             },

src/tools/clippy/clippy_lints/src/redundant_type_annotations.rs

@@ -200,7 +200,7 @@ impl LateLintPass<'_> for RedundantTypeAnnotations {
                                 span_lint(cx, REDUNDANT_TYPE_ANNOTATIONS, local.span, "redundant type annotation");
                             }
                         },
-                        LitKind::Err => (),
+                        LitKind::Err(_) => (),
                         LitKind::ByteStr(..) => {
                             // We only lint if the type annotation is an array type (e.g. &[u8; 4]).
                             // If instead it is a slice (e.g. &[u8]) it may not be redundant, so we

src/tools/clippy/clippy_lints/src/utils/author.rs

@@ -279,7 +279,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
         match lit.value.node {
             LitKind::Bool(val) => kind!("Bool({val:?})"),
             LitKind::Char(c) => kind!("Char({c:?})"),
-            LitKind::Err => kind!("Err"),
+            LitKind::Err(_) => kind!("Err"),
             LitKind::Byte(b) => kind!("Byte({b})"),
             LitKind::Int(i, suffix) => {
                 let int_ty = match suffix {

src/tools/clippy/clippy_utils/src/consts.rs

@@ -286,7 +286,7 @@ pub fn lit_to_mir_constant<'tcx>(lit: &LitKind, ty: Option<Ty<'tcx>>) -> Constan
             _ => bug!(),
         },
         LitKind::Bool(b) => Constant::Bool(b),
-        LitKind::Err => Constant::Err,
+        LitKind::Err(_) => Constant::Err,
     }
 }
 

src/tools/clippy/tests/ui/match_str_case_mismatch.stderr

@@ -17,7 +17,7 @@ error: this `match` arm has a differing case than its expression
 LL |         "~!@#$%^&*()-_=+Foo" => {},
    |         ^^^^^^^^^^^^^^^^^^^^
    |
-help: consider changing the case of this arm to respect `to_ascii_lowercase`
+help: consider changing the case of this arm to respect `to_ascii_lowercase` (notice the capitalization difference)
    |
 LL |         "~!@#$%^&*()-_=+foo" => {},
    |         ~~~~~~~~~~~~~~~~~~~~

src/tools/rust-analyzer/crates/proc-macro-srv/src/server/rust_analyzer_span.rs

@@ -72,7 +72,7 @@ impl server::FreeFunctions for RaSpanServer {
     ) -> Result<bridge::Literal<Self::Span, Self::Symbol>, ()> {
         // FIXME: keep track of LitKind and Suffix
         Ok(bridge::Literal {
-            kind: bridge::LitKind::Err,
+            kind: bridge::LitKind::Integer, // dummy
             symbol: Symbol::intern(self.interner, s),
             suffix: None,
             span: self.call_site,
@@ -202,7 +202,7 @@ impl server::TokenStream for RaSpanServer {
                 tt::TokenTree::Leaf(tt::Leaf::Literal(lit)) => {
                     bridge::TokenTree::Literal(bridge::Literal {
                         // FIXME: handle literal kinds
-                        kind: bridge::LitKind::Err,
+                        kind: bridge::LitKind::Integer, // dummy
                         symbol: Symbol::intern(self.interner, &lit.text),
                         // FIXME: handle suffixes
                         suffix: None,

src/tools/rust-analyzer/crates/proc-macro-srv/src/server/token_id.rs

@@ -64,7 +64,7 @@ impl server::FreeFunctions for TokenIdServer {
     ) -> Result<bridge::Literal<Self::Span, Self::Symbol>, ()> {
         // FIXME: keep track of LitKind and Suffix
         Ok(bridge::Literal {
-            kind: bridge::LitKind::Err,
+            kind: bridge::LitKind::Integer, // dummy
             symbol: Symbol::intern(self.interner, s),
             suffix: None,
             span: self.call_site,
@@ -187,7 +187,7 @@ impl server::TokenStream for TokenIdServer {
                 tt::TokenTree::Leaf(tt::Leaf::Literal(lit)) => {
                     bridge::TokenTree::Literal(bridge::Literal {
                         // FIXME: handle literal kinds
-                        kind: bridge::LitKind::Err,
+                        kind: bridge::LitKind::Integer, // dummy
                         symbol: Symbol::intern(self.interner, &lit.text),
                         // FIXME: handle suffixes
                         suffix: None,

tests/ui/asm/x86_64/evex512-implicit-feature.rs

@@ -0,0 +1,15 @@
+// build-pass
+// only-x86_64
+// compile-flags: --crate-type=lib -C target-cpu=skylake
+
+#![feature(avx512_target_feature)]
+#![feature(stdarch_x86_avx512)]
+
+use std::arch::x86_64::*;
+
+#[target_feature(enable = "avx512f")]
+#[no_mangle]
+pub unsafe fn test(res: *mut f64, p: *const f64) {
+    let arg = _mm512_load_pd(p);
+    _mm512_store_pd(res, _mm512_fmaddsub_pd(arg, arg, arg));
+}

tests/ui/const-generics/wrong-normalization.rs

@@ -15,5 +15,6 @@ pub struct I8<const F: i8>;
 
 impl <I8<{i8::MIN}> as Identity>::Identity {
 //~^ ERROR no nominal type found for inherent implementation
+//~| ERROR no associated item named `MIN` found for type `i8`
     pub fn foo(&self) {}
 }

tests/ui/const-generics/wrong-normalization.stderr

@@ -6,6 +6,18 @@ LL | impl <I8<{i8::MIN}> as Identity>::Identity {
    |
    = note: either implement a trait on it or create a newtype to wrap it instead
 
-error: aborting due to 1 previous error
+error[E0599]: no associated item named `MIN` found for type `i8` in the current scope
+  --> $DIR/wrong-normalization.rs:16:15
+   |
+LL | impl <I8<{i8::MIN}> as Identity>::Identity {
+   |               ^^^ associated item not found in `i8`
+   |
+help: you are looking for the module in `std`, not the primitive type
+   |
+LL | impl <I8<{std::i8::MIN}> as Identity>::Identity {
+   |           +++++
 
-For more information about this error, try `rustc --explain E0118`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0118, E0599.
+For more information about an error, try `rustc --explain E0118`.

tests/ui/error-codes/E0423.stderr

@@ -53,7 +53,7 @@ help: use struct literal syntax instead
    |
 LL |     let f = Foo { a: val };
    |             ~~~~~~~~~~~~~~
-help: a function with a similar name exists
+help: a function with a similar name exists (notice the capitalization difference)
    |
 LL |     let f = foo();
    |             ~~~

tests/ui/impl-trait/where-allowed.rs

@@ -44,6 +44,7 @@ fn in_dyn_Fn_parameter_in_return() -> &'static dyn Fn(impl Debug) { panic!() }
 
 // Allowed
 fn in_dyn_Fn_return_in_return() -> &'static dyn Fn() -> impl Debug { panic!() }
+//~^ ERROR: type annotations needed
 
 // Disallowed
 fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
@@ -58,9 +59,11 @@ fn in_impl_Fn_return_in_parameters(_: &impl Fn() -> impl Debug) { panic!() }
 fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic!() }
 //~^ ERROR `impl Trait` is not allowed in the parameters of `Fn` trait bounds
 //~| ERROR nested `impl Trait` is not allowed
+//~| ERROR: type annotations needed
 
 // Allowed
 fn in_impl_Fn_return_in_return() -> &'static impl Fn() -> impl Debug { panic!() }
+//~^ ERROR: type annotations needed
 
 // Disallowed
 fn in_Fn_parameter_in_generics<F: Fn(impl Debug)> (_: F) { panic!() }
@@ -77,6 +80,7 @@ fn in_impl_Trait_in_parameters(_: impl Iterator<Item = impl Iterator>) { panic!(
 // Allowed
 fn in_impl_Trait_in_return() -> impl IntoIterator<Item = impl IntoIterator> {
     vec![vec![0; 10], vec![12; 7], vec![8; 3]]
+    //~^ ERROR: no function or associated item named `into_vec` found for slice `[_]`
 }
 
 // Disallowed
@@ -118,11 +122,13 @@ trait DummyTrait {
 impl DummyTrait for () {
     type Out = impl Debug;
     //~^ ERROR `impl Trait` in associated types is unstable
+    //~| ERROR unconstrained opaque type
 
     fn in_trait_impl_parameter(_: impl Debug) { }
     // Allowed
 
     fn in_trait_impl_return() -> impl Debug { () }
+    //~^ ERROR `in_trait_impl_return` has an incompatible type for trait
     // Allowed
 }
 

tests/ui/impl-trait/where-allowed.stderr

@@ -1,5 +1,5 @@
 error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/where-allowed.rs:49:51
+  --> $DIR/where-allowed.rs:50:51
    |
 LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    |                                           --------^^^^^^^^^^-
@@ -8,7 +8,7 @@ LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    |                                           outer `impl Trait`
 
 error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/where-allowed.rs:58:57
+  --> $DIR/where-allowed.rs:59:57
    |
 LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic!() }
    |                                                 --------^^^^^^^^^^-
@@ -17,7 +17,7 @@ LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic
    |                                                 outer `impl Trait`
 
 error[E0658]: `impl Trait` in associated types is unstable
-  --> $DIR/where-allowed.rs:119:16
+  --> $DIR/where-allowed.rs:123:16
    |
 LL |     type Out = impl Debug;
    |                ^^^^^^^^^^
@@ -27,7 +27,7 @@ LL |     type Out = impl Debug;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:154:23
+  --> $DIR/where-allowed.rs:160:23
    |
 LL | type InTypeAlias<R> = impl Debug;
    |                       ^^^^^^^^^^
@@ -37,7 +37,7 @@ LL | type InTypeAlias<R> = impl Debug;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:157:39
+  --> $DIR/where-allowed.rs:163:39
    |
 LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    |                                       ^^^^^^^^^^
@@ -103,7 +103,7 @@ LL | fn in_dyn_Fn_parameter_in_return() -> &'static dyn Fn(impl Debug) { panic!(
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the parameters of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:49:51
+  --> $DIR/where-allowed.rs:50:51
    |
 LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    |                                                   ^^^^^^^^^^
@@ -111,7 +111,7 @@ LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the return type of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:54:53
+  --> $DIR/where-allowed.rs:55:53
    |
 LL | fn in_impl_Fn_return_in_parameters(_: &impl Fn() -> impl Debug) { panic!() }
    |                                                     ^^^^^^^^^^
@@ -119,7 +119,7 @@ LL | fn in_impl_Fn_return_in_parameters(_: &impl Fn() -> impl Debug) { panic!()
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the parameters of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:58:57
+  --> $DIR/where-allowed.rs:59:57
    |
 LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic!() }
    |                                                         ^^^^^^^^^^
@@ -127,7 +127,7 @@ LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the parameters of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:66:38
+  --> $DIR/where-allowed.rs:69:38
    |
 LL | fn in_Fn_parameter_in_generics<F: Fn(impl Debug)> (_: F) { panic!() }
    |                                      ^^^^^^^^^^
@@ -135,7 +135,7 @@ LL | fn in_Fn_parameter_in_generics<F: Fn(impl Debug)> (_: F) { panic!() }
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the return type of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:70:40
+  --> $DIR/where-allowed.rs:73:40
    |
 LL | fn in_Fn_return_in_generics<F: Fn() -> impl Debug> (_: F) { panic!() }
    |                                        ^^^^^^^^^^
@@ -143,7 +143,7 @@ LL | fn in_Fn_return_in_generics<F: Fn() -> impl Debug> (_: F) { panic!() }
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in field types
-  --> $DIR/where-allowed.rs:83:32
+  --> $DIR/where-allowed.rs:87:32
    |
 LL | struct InBraceStructField { x: impl Debug }
    |                                ^^^^^^^^^^
@@ -151,7 +151,7 @@ LL | struct InBraceStructField { x: impl Debug }
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in field types
-  --> $DIR/where-allowed.rs:87:41
+  --> $DIR/where-allowed.rs:91:41
    |
 LL | struct InAdtInBraceStructField { x: Vec<impl Debug> }
    |                                         ^^^^^^^^^^
@@ -159,7 +159,7 @@ LL | struct InAdtInBraceStructField { x: Vec<impl Debug> }
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in field types
-  --> $DIR/where-allowed.rs:91:27
+  --> $DIR/where-allowed.rs:95:27
    |
 LL | struct InTupleStructField(impl Debug);
    |                           ^^^^^^^^^^
@@ -167,7 +167,7 @@ LL | struct InTupleStructField(impl Debug);
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in field types
-  --> $DIR/where-allowed.rs:96:25
+  --> $DIR/where-allowed.rs:100:25
    |
 LL |     InBraceVariant { x: impl Debug },
    |                         ^^^^^^^^^^
@@ -175,7 +175,7 @@ LL |     InBraceVariant { x: impl Debug },
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in field types
-  --> $DIR/where-allowed.rs:98:20
+  --> $DIR/where-allowed.rs:102:20
    |
 LL |     InTupleVariant(impl Debug),
    |                    ^^^^^^^^^^
@@ -183,7 +183,7 @@ LL |     InTupleVariant(impl Debug),
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in `extern fn` parameters
-  --> $DIR/where-allowed.rs:138:33
+  --> $DIR/where-allowed.rs:144:33
    |
 LL |     fn in_foreign_parameters(_: impl Debug);
    |                                 ^^^^^^^^^^
@@ -191,7 +191,7 @@ LL |     fn in_foreign_parameters(_: impl Debug);
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in `extern fn` return types
-  --> $DIR/where-allowed.rs:141:31
+  --> $DIR/where-allowed.rs:147:31
    |
 LL |     fn in_foreign_return() -> impl Debug;
    |                               ^^^^^^^^^^
@@ -199,7 +199,7 @@ LL |     fn in_foreign_return() -> impl Debug;
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in `fn` pointer return types
-  --> $DIR/where-allowed.rs:157:39
+  --> $DIR/where-allowed.rs:163:39
    |
 LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    |                                       ^^^^^^^^^^
@@ -207,7 +207,7 @@ LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in traits
-  --> $DIR/where-allowed.rs:162:16
+  --> $DIR/where-allowed.rs:168:16
    |
 LL | impl PartialEq<impl Debug> for () {
    |                ^^^^^^^^^^
@@ -215,7 +215,7 @@ LL | impl PartialEq<impl Debug> for () {
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in impl headers
-  --> $DIR/where-allowed.rs:167:24
+  --> $DIR/where-allowed.rs:173:24
    |
 LL | impl PartialEq<()> for impl Debug {
    |                        ^^^^^^^^^^
@@ -223,7 +223,7 @@ LL | impl PartialEq<()> for impl Debug {
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in impl headers
-  --> $DIR/where-allowed.rs:172:6
+  --> $DIR/where-allowed.rs:178:6
    |
 LL | impl impl Debug {
    |      ^^^^^^^^^^
@@ -231,7 +231,7 @@ LL | impl impl Debug {
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in impl headers
-  --> $DIR/where-allowed.rs:178:24
+  --> $DIR/where-allowed.rs:184:24
    |
 LL | impl InInherentImplAdt<impl Debug> {
    |                        ^^^^^^^^^^
@@ -239,7 +239,7 @@ LL | impl InInherentImplAdt<impl Debug> {
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in bounds
-  --> $DIR/where-allowed.rs:184:11
+  --> $DIR/where-allowed.rs:190:11
    |
 LL |     where impl Debug: Debug
    |           ^^^^^^^^^^
@@ -247,7 +247,7 @@ LL |     where impl Debug: Debug
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in bounds
-  --> $DIR/where-allowed.rs:191:15
+  --> $DIR/where-allowed.rs:197:15
    |
 LL |     where Vec<impl Debug>: Debug
    |               ^^^^^^^^^^
@@ -255,7 +255,7 @@ LL |     where Vec<impl Debug>: Debug
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in bounds
-  --> $DIR/where-allowed.rs:198:24
+  --> $DIR/where-allowed.rs:204:24
    |
 LL |     where T: PartialEq<impl Debug>
    |                        ^^^^^^^^^^
@@ -263,7 +263,7 @@ LL |     where T: PartialEq<impl Debug>
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the parameters of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:205:17
+  --> $DIR/where-allowed.rs:211:17
    |
 LL |     where T: Fn(impl Debug)
    |                 ^^^^^^^^^^
@@ -271,7 +271,7 @@ LL |     where T: Fn(impl Debug)
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the return type of `Fn` trait bounds
-  --> $DIR/where-allowed.rs:212:22
+  --> $DIR/where-allowed.rs:218:22
    |
 LL |     where T: Fn() -> impl Debug
    |                      ^^^^^^^^^^
@@ -279,7 +279,7 @@ LL |     where T: Fn() -> impl Debug
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in generic parameter defaults
-  --> $DIR/where-allowed.rs:218:40
+  --> $DIR/where-allowed.rs:224:40
    |
 LL | struct InStructGenericParamDefault<T = impl Debug>(T);
    |                                        ^^^^^^^^^^
@@ -287,7 +287,7 @@ LL | struct InStructGenericParamDefault<T = impl Debug>(T);
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in generic parameter defaults
-  --> $DIR/where-allowed.rs:222:36
+  --> $DIR/where-allowed.rs:228:36
    |
 LL | enum InEnumGenericParamDefault<T = impl Debug> { Variant(T) }
    |                                    ^^^^^^^^^^
@@ -295,7 +295,7 @@ LL | enum InEnumGenericParamDefault<T = impl Debug> { Variant(T) }
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in generic parameter defaults
-  --> $DIR/where-allowed.rs:226:38
+  --> $DIR/where-allowed.rs:232:38
    |
 LL | trait InTraitGenericParamDefault<T = impl Debug> {}
    |                                      ^^^^^^^^^^
@@ -303,7 +303,7 @@ LL | trait InTraitGenericParamDefault<T = impl Debug> {}
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in generic parameter defaults
-  --> $DIR/where-allowed.rs:230:41
+  --> $DIR/where-allowed.rs:236:41
    |
 LL | type InTypeAliasGenericParamDefault<T = impl Debug> = T;
    |                                         ^^^^^^^^^^
@@ -311,7 +311,7 @@ LL | type InTypeAliasGenericParamDefault<T = impl Debug> = T;
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in generic parameter defaults
-  --> $DIR/where-allowed.rs:234:11
+  --> $DIR/where-allowed.rs:240:11
    |
 LL | impl <T = impl Debug> T {}
    |           ^^^^^^^^^^
@@ -319,7 +319,7 @@ LL | impl <T = impl Debug> T {}
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in generic parameter defaults
-  --> $DIR/where-allowed.rs:241:40
+  --> $DIR/where-allowed.rs:247:40
    |
 LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    |                                        ^^^^^^^^^^
@@ -327,7 +327,7 @@ LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in the type of variable bindings
-  --> $DIR/where-allowed.rs:247:29
+  --> $DIR/where-allowed.rs:253:29
    |
 LL |     let _in_local_variable: impl Fn() = || {};
    |                             ^^^^^^^^^
@@ -335,7 +335,7 @@ LL |     let _in_local_variable: impl Fn() = || {};
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error[E0562]: `impl Trait` is not allowed in closure return types
-  --> $DIR/where-allowed.rs:249:46
+  --> $DIR/where-allowed.rs:255:46
    |
 LL |     let _in_return_in_local_variable = || -> impl Fn() { || {} };
    |                                              ^^^^^^^^^
@@ -343,7 +343,7 @@ LL |     let _in_return_in_local_variable = || -> impl Fn() { || {} };
    = note: `impl Trait` is only allowed in arguments and return types of functions and methods
 
 error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
-  --> $DIR/where-allowed.rs:234:7
+  --> $DIR/where-allowed.rs:240:7
    |
 LL | impl <T = impl Debug> T {}
    |       ^^^^^^^^^^^^^^
@@ -353,7 +353,7 @@ LL | impl <T = impl Debug> T {}
    = note: `#[deny(invalid_type_param_default)]` on by default
 
 error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
-  --> $DIR/where-allowed.rs:241:36
+  --> $DIR/where-allowed.rs:247:36
    |
 LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    |                                    ^^^^^^^^^^^^^^
@@ -362,14 +362,77 @@ LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
 
 error[E0118]: no nominal type found for inherent implementation
-  --> $DIR/where-allowed.rs:234:1
+  --> $DIR/where-allowed.rs:240:1
    |
 LL | impl <T = impl Debug> T {}
    | ^^^^^^^^^^^^^^^^^^^^^^^ impl requires a nominal type
    |
    = note: either implement a trait on it or create a newtype to wrap it instead
 
-error: aborting due to 45 previous errors
+error[E0283]: type annotations needed
+  --> $DIR/where-allowed.rs:46:57
+   |
+LL | fn in_dyn_Fn_return_in_return() -> &'static dyn Fn() -> impl Debug { panic!() }
+   |                                                         ^^^^^^^^^^ cannot infer type
+   |
+   = note: cannot satisfy `_: Debug`
 
-Some errors have detailed explanations: E0118, E0562, E0658, E0666.
+error[E0282]: type annotations needed
-For more information about an error, try `rustc --explain E0118`.
+  --> $DIR/where-allowed.rs:59:49
+   |
+LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic!() }
+   |                                                 ^^^^^^^^^^^^^^^^^^^ cannot infer type
+
+error[E0283]: type annotations needed
+  --> $DIR/where-allowed.rs:65:46
+   |
+LL | fn in_impl_Fn_return_in_return() -> &'static impl Fn() -> impl Debug { panic!() }
+   |                                              ^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type
+   |
+   = note: multiple `impl`s satisfying `_: Fn()` found in the following crates: `alloc`, `core`:
+           - impl<A, F> Fn<A> for &F
+             where A: Tuple, F: Fn<A>, F: ?Sized;
+           - impl<Args, F, A> Fn<Args> for Box<F, A>
+             where Args: Tuple, F: Fn<Args>, A: Allocator, F: ?Sized;
+
+error[E0599]: no function or associated item named `into_vec` found for slice `[_]` in the current scope
+  --> $DIR/where-allowed.rs:82:5
+   |
+LL |     vec![vec![0; 10], vec![12; 7], vec![8; 3]]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function or associated item not found in `[_]`
+   |
+   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0053]: method `in_trait_impl_return` has an incompatible type for trait
+  --> $DIR/where-allowed.rs:130:34
+   |
+LL |     type Out = impl Debug;
+   |                ---------- the expected opaque type
+...
+LL |     fn in_trait_impl_return() -> impl Debug { () }
+   |                                  ^^^^^^^^^^
+   |                                  |
+   |                                  expected opaque type, found a different opaque type
+   |                                  help: change the output type to match the trait: `<() as DummyTrait>::Out`
+   |
+note: type in trait
+  --> $DIR/where-allowed.rs:120:34
+   |
+LL |     fn in_trait_impl_return() -> Self::Out;
+   |                                  ^^^^^^^^^
+   = note: expected signature `fn() -> <() as DummyTrait>::Out`
+              found signature `fn() -> impl Debug`
+   = note: distinct uses of `impl Trait` result in different opaque types
+
+error: unconstrained opaque type
+  --> $DIR/where-allowed.rs:123:16
+   |
+LL |     type Out = impl Debug;
+   |                ^^^^^^^^^^
+   |
+   = note: `Out` must be used in combination with a concrete type within the same impl
+
+error: aborting due to 51 previous errors
+
+Some errors have detailed explanations: E0053, E0118, E0282, E0283, E0562, E0599, E0658, E0666.
+For more information about an error, try `rustc --explain E0053`.

tests/ui/issues/issue-4265.rs

@@ -5,6 +5,7 @@ struct Foo {
 impl Foo {
     fn bar() {
         Foo { baz: 0 }.bar();
+        //~^ ERROR: no method named `bar` found
     }
 
     fn bar() { //~ ERROR duplicate definitions

tests/ui/issues/issue-4265.stderr

@@ -1,5 +1,5 @@
 error[E0592]: duplicate definitions with name `bar`
-  --> $DIR/issue-4265.rs:10:5
+  --> $DIR/issue-4265.rs:11:5
    |
 LL |     fn bar() {
    |     -------- other definition for `bar`
@@ -7,6 +7,26 @@ LL |     fn bar() {
 LL |     fn bar() {
    |     ^^^^^^^^ duplicate definitions for `bar`
 
-error: aborting due to 1 previous error
+error[E0599]: no method named `bar` found for struct `Foo` in the current scope
+  --> $DIR/issue-4265.rs:7:24
+   |
+LL | struct Foo {
+   | ---------- method `bar` not found for this struct
+...
+LL |         Foo { baz: 0 }.bar();
+   |         ---------------^^^--
+   |         |              |
+   |         |              this is an associated function, not a method
+   |         help: use associated function syntax instead: `Foo::bar()`
+   |
+   = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
+note: the candidate is defined in an impl for the type `Foo`
+  --> $DIR/issue-4265.rs:6:5
+   |
+LL |     fn bar() {
+   |     ^^^^^^^^
 
-For more information about this error, try `rustc --explain E0592`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0592, E0599.
+For more information about an error, try `rustc --explain E0592`.

tests/ui/kinds-of-primitive-impl.rs

@@ -6,7 +6,7 @@ impl u8 {
 impl str {
 //~^ error: cannot define inherent `impl` for primitive types
     fn foo() {}
-    fn bar(self) {}
+    fn bar(self) {} //~ ERROR: size for values of type `str` cannot be known
 }
 
 impl char {

tests/ui/kinds-of-primitive-impl.stderr

@@ -31,6 +31,20 @@ LL | impl &MyType {
    = help: consider using an extension trait instead
    = note: you could also try moving the reference to uses of `MyType` (such as `self`) within the implementation
 
-error: aborting due to 4 previous errors
+error[E0277]: the size for values of type `str` cannot be known at compilation time
+  --> $DIR/kinds-of-primitive-impl.rs:9:12
+   |
+LL |     fn bar(self) {}
+   |            ^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `str`
+   = help: unsized fn params are gated as an unstable feature
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL |     fn bar(&self) {}
+   |            +
 
-For more information about this error, try `rustc --explain E0390`.
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0277, E0390.
+For more information about an error, try `rustc --explain E0277`.

tests/ui/lint/reference_casting.rs

@@ -239,6 +239,11 @@ unsafe fn bigger_layout() {
         //~^ ERROR casting references to a bigger memory layout
     }
 
+    {
+        let x: Box<dyn Send> = Box::new(0i32);
+        let _z = unsafe { &*(&*x as *const dyn Send as *const i32) };
+    }
+
     unsafe fn from_ref(this: &i32) -> &i64 {
         &*(this as *const i32 as *const i64)
     }

tests/ui/parser/impl-item-type-no-body-semantic-fail.rs

@@ -14,8 +14,10 @@ impl X {
     //~^ ERROR associated type in `impl` without body
     //~| ERROR bounds on `type`s in `impl`s have no effect
     //~| ERROR inherent associated types are unstable
+    //~| ERROR `X: Eq` is not satisfied
     type W where Self: Eq;
     //~^ ERROR associated type in `impl` without body
     //~| ERROR inherent associated types are unstable
     //~| ERROR duplicate definitions
+    //~| ERROR `X: Eq` is not satisfied
 }

tests/ui/parser/impl-item-type-no-body-semantic-fail.stderr

@@ -35,7 +35,7 @@ LL |     type W: Ord where Self: Eq;
    |             ^^^
 
 error: associated type in `impl` without body
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:17:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:18:5
    |
 LL |     type W where Self: Eq;
    |     ^^^^^^^^^^^^^^^^^^^^^-
@@ -73,7 +73,7 @@ LL |     type W: Ord where Self: Eq;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: inherent associated types are unstable
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:17:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:18:5
    |
 LL |     type W where Self: Eq;
    |     ^^^^^^^^^^^^^^^^^^^^^^
@@ -83,7 +83,7 @@ LL |     type W where Self: Eq;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0592]: duplicate definitions with name `W`
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:17:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:18:5
    |
 LL |     type W: Ord where Self: Eq;
    |     ------ other definition for `W`
@@ -91,7 +91,35 @@ LL |     type W: Ord where Self: Eq;
 LL |     type W where Self: Eq;
    |     ^^^^^^ duplicate definitions for `W`
 
-error: aborting due to 11 previous errors
+error[E0277]: the trait bound `X: Eq` is not satisfied
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:13:23
+   |
+LL |     type W: Ord where Self: Eq;
+   |                       ^^^^^^^^ the trait `Eq` is not implemented for `X`
+   |
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: consider annotating `X` with `#[derive(Eq)]`
+   |
+LL + #[derive(Eq)]
+LL | struct X;
+   |
 
-Some errors have detailed explanations: E0592, E0658.
+error[E0277]: the trait bound `X: Eq` is not satisfied
-For more information about an error, try `rustc --explain E0592`.
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:18:18
+   |
+LL |     type W where Self: Eq;
+   |                  ^^^^^^^^ the trait `Eq` is not implemented for `X`
+   |
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: consider annotating `X` with `#[derive(Eq)]`
+   |
+LL + #[derive(Eq)]
+LL | struct X;
+   |
+
+error: aborting due to 13 previous errors
+
+Some errors have detailed explanations: E0277, E0592, E0658.
+For more information about an error, try `rustc --explain E0277`.

tests/ui/parser/kw-in-trait-bounds.stderr

@@ -4,7 +4,7 @@ error: expected identifier, found keyword `fn`
 LL | fn _f<F: fn(), G>(_: impl fn(), _: &dyn fn())
    |          ^^
    |
-help: use `Fn` to refer to the trait
+help: use `Fn` to refer to the trait (notice the capitalization difference)
    |
 LL | fn _f<F: Fn(), G>(_: impl fn(), _: &dyn fn())
    |          ~~
@@ -15,7 +15,7 @@ error: expected identifier, found keyword `fn`
 LL | fn _f<F: fn(), G>(_: impl fn(), _: &dyn fn())
    |                           ^^
    |
-help: use `Fn` to refer to the trait
+help: use `Fn` to refer to the trait (notice the capitalization difference)
    |
 LL | fn _f<F: fn(), G>(_: impl Fn(), _: &dyn fn())
    |                           ~~
@@ -26,7 +26,7 @@ error: expected identifier, found keyword `fn`
 LL | fn _f<F: fn(), G>(_: impl fn(), _: &dyn fn())
    |                                         ^^
    |
-help: use `Fn` to refer to the trait
+help: use `Fn` to refer to the trait (notice the capitalization difference)
    |
 LL | fn _f<F: fn(), G>(_: impl fn(), _: &dyn Fn())
    |                                         ~~
@@ -37,7 +37,7 @@ error: expected identifier, found keyword `fn`
 LL | G: fn(),
    |    ^^
    |
-help: use `Fn` to refer to the trait
+help: use `Fn` to refer to the trait (notice the capitalization difference)
    |
 LL | G: Fn(),
    |    ~~

tests/ui/parser/recover/recover-fn-trait-from-fn-kw.stderr

@@ -4,7 +4,7 @@ error: expected identifier, found keyword `fn`
 LL | fn foo(_: impl fn() -> i32) {}
    |                ^^
    |
-help: use `Fn` to refer to the trait
+help: use `Fn` to refer to the trait (notice the capitalization difference)
    |
 LL | fn foo(_: impl Fn() -> i32) {}
    |                ~~
@@ -15,7 +15,7 @@ error: expected identifier, found keyword `fn`
 LL | fn foo2<T: fn(i32)>(_: T) {}
    |            ^^
    |
-help: use `Fn` to refer to the trait
+help: use `Fn` to refer to the trait (notice the capitalization difference)
    |
 LL | fn foo2<T: Fn(i32)>(_: T) {}
    |            ~~

tests/ui/parser/typod-const-in-const-param-def.stderr

@@ -4,7 +4,7 @@ error: `const` keyword was mistyped as `Const`
 LL | pub fn foo<Const N: u8>() {}
    |            ^^^^^
    |
-help: use the `const` keyword
+help: use the `const` keyword (notice the capitalization difference)
    |
 LL | pub fn foo<const N: u8>() {}
    |            ~~~~~
@@ -15,7 +15,7 @@ error: `const` keyword was mistyped as `Const`
 LL | pub fn baz<Const N: u8, T>() {}
    |            ^^^^^
    |
-help: use the `const` keyword
+help: use the `const` keyword (notice the capitalization difference)
    |
 LL | pub fn baz<const N: u8, T>() {}
    |            ~~~~~
@@ -26,7 +26,7 @@ error: `const` keyword was mistyped as `Const`
 LL | pub fn qux<T, Const N: u8>() {}
    |               ^^^^^
    |
-help: use the `const` keyword
+help: use the `const` keyword (notice the capitalization difference)
    |
 LL | pub fn qux<T, const N: u8>() {}
    |               ~~~~~
@@ -37,7 +37,7 @@ error: `const` keyword was mistyped as `Const`
 LL | pub fn quux<T, Const N: u8, U>() {}
    |                ^^^^^
    |
-help: use the `const` keyword
+help: use the `const` keyword (notice the capitalization difference)
    |
 LL | pub fn quux<T, const N: u8, U>() {}
    |                ~~~~~

tests/ui/suggestions/assoc-ct-for-assoc-method.stderr

@@ -8,7 +8,7 @@ LL |     let x: i32 = MyS::foo;
    |
    = note: expected type `i32`
            found fn item `fn() -> MyS {MyS::foo}`
-help: try referring to the associated const `FOO` instead
+help: try referring to the associated const `FOO` instead (notice the capitalization difference)
    |
 LL |     let x: i32 = MyS::FOO;
    |                       ~~~

tests/ui/suggestions/bool_typo_err_suggest.stderr

@@ -15,7 +15,7 @@ error[E0425]: cannot find value `False` in this scope
 LL |     let y = False;
    |             ^^^^^ not found in this scope
    |
-help: you may want to use a bool value instead
+help: you may want to use a bool value instead (notice the capitalization difference)
    |
 LL |     let y = false;
    |             ~~~~~

tests/ui/traits/issue-33140.rs

@@ -43,5 +43,7 @@ fn main() {
     assert_eq!(<dyn Send + Sync>::uvw(), false);
     assert_eq!(<dyn Sync + Send+ Sync>::uvw(), true);
     assert_eq!(<Foo<dyn Send + Sync>>::abc(), false);
+    //~^ ERROR: multiple applicable items in scope
     assert_eq!(<Foo<dyn Sync + Send>>::abc(), true);
+    //~^ ERROR: multiple applicable items in scope
 }

tests/ui/traits/issue-33140.stderr

@@ -25,7 +25,41 @@ LL |     fn abc() -> bool {
 LL |     fn abc() -> bool {
    |     ---------------- other definition for `abc`
 
-error: aborting due to 3 previous errors
+error[E0034]: multiple applicable items in scope
+  --> $DIR/issue-33140.rs:45:40
+   |
+LL |     assert_eq!(<Foo<dyn Send + Sync>>::abc(), false);
+   |                                        ^^^ multiple `abc` found
+   |
+note: candidate #1 is defined in an impl for the type `Foo<(dyn Send + Sync + 'static)>`
+  --> $DIR/issue-33140.rs:29:5
+   |
+LL |     fn abc() -> bool {
+   |     ^^^^^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `Foo<(dyn Send + Sync + 'static)>`
+  --> $DIR/issue-33140.rs:35:5
+   |
+LL |     fn abc() -> bool {
+   |     ^^^^^^^^^^^^^^^^
 
-Some errors have detailed explanations: E0119, E0592.
+error[E0034]: multiple applicable items in scope
-For more information about an error, try `rustc --explain E0119`.
+  --> $DIR/issue-33140.rs:47:40
+   |
+LL |     assert_eq!(<Foo<dyn Sync + Send>>::abc(), true);
+   |                                        ^^^ multiple `abc` found
+   |
+note: candidate #1 is defined in an impl for the type `Foo<(dyn Send + Sync + 'static)>`
+  --> $DIR/issue-33140.rs:29:5
+   |
+LL |     fn abc() -> bool {
+   |     ^^^^^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `Foo<(dyn Send + Sync + 'static)>`
+  --> $DIR/issue-33140.rs:35:5
+   |
+LL |     fn abc() -> bool {
+   |     ^^^^^^^^^^^^^^^^
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0034, E0119, E0592.
+For more information about an error, try `rustc --explain E0034`.