Auto merge of #134201 - matthiaskrgr:rollup-22b721y, r=matthiaskrgr

Rollup of 11 pull requests

Successful merges:

 - #122003 (link libunwind dynamically and allow controlling it via `crt-static` on gnullvm targets)
 - #133859 (Move some alloc tests to the alloctests crate)
 - #134070 (Some asm! diagnostic adjustments and a papercut fix)
 - #134144 (Properly consider APITs for never type fallback ascription fix)
 - #134152 (Simplify `rustc_mir_dataflow::abs_domain`.)
 - #134154 (suppress field expr with generics error message if it's a method)
 - #134155 (Forbid `unsafe_op_in_unsafe_fn` for Hurd)
 - #134173 (allow `symbol_intern_string_literal` lint in test modules)
 - #134178 (Stabilize the Rust 2024 prelude)
 - #134179 (Remove outdated consteval note from `<*mut T>::align_offset` docs.)
 - #134187 (Remove `PErr`.)

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

compiler/rustc_ast/src/util/comments/tests.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
+
 use rustc_span::create_default_session_globals_then;
 
 use super::*;

compiler/rustc_errors/src/lib.rs

@@ -94,8 +94,7 @@ mod styled_buffer;
 mod tests;
 pub mod translation;
 
-pub type PErr<'a> = Diag<'a>;
+pub type PResult<'a, T> = Result<T, Diag<'a>>;
-pub type PResult<'a, T> = Result<T, PErr<'a>>;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
@@ -576,6 +575,10 @@ pub enum StashKey {
     UndeterminedMacroResolution,
     /// Used by `Parser::maybe_recover_trailing_expr`
     ExprInPat,
+    /// If in the parser we detect a field expr with turbofish generic params it's possible that
+    /// it's a method call without parens. If later on in `hir_typeck` we find out that this is
+    /// the case we suppress this message and we give a better suggestion.
+    GenericInFieldExpr,
 }
 
 fn default_track_diagnostic<R>(diag: DiagInner, f: &mut dyn FnMut(DiagInner) -> R) -> R {

compiler/rustc_hir/src/tests.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
+
 use rustc_data_structures::stable_hasher::Hash64;
 use rustc_span::def_id::{DefPathHash, StableCrateId};
 use rustc_span::edition::Edition;

compiler/rustc_hir_analysis/src/check/intrinsicck.rs

@@ -3,6 +3,7 @@ use std::assert_matches::debug_assert_matches;
 use rustc_abi::FieldIdx;
 use rustc_ast::InlineAsmTemplatePiece;
 use rustc_data_structures::fx::FxIndexSet;
+use rustc_hir::def_id::DefId;
 use rustc_hir::{self as hir, LangItem};
 use rustc_middle::bug;
 use rustc_middle::ty::{self, FloatTy, IntTy, Ty, TyCtxt, TypeVisitableExt, UintTy};
@@ -21,6 +22,12 @@ pub struct InlineAsmCtxt<'a, 'tcx> {
     get_operand_ty: Box<dyn Fn(&'tcx hir::Expr<'tcx>) -> Ty<'tcx> + 'a>,
 }
 
+enum NonAsmTypeReason<'tcx> {
+    UnevaluatedSIMDArrayLength(DefId, ty::Const<'tcx>),
+    Invalid(Ty<'tcx>),
+    InvalidElement(DefId, Ty<'tcx>),
+}
+
 impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
     pub fn new_global_asm(tcx: TyCtxt<'tcx>) -> Self {
         InlineAsmCtxt {
@@ -56,7 +63,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
         false
     }
 
-    fn get_asm_ty(&self, ty: Ty<'tcx>) -> Option<InlineAsmType> {
+    fn get_asm_ty(&self, ty: Ty<'tcx>) -> Result<InlineAsmType, NonAsmTypeReason<'tcx>> {
         let asm_ty_isize = match self.tcx.sess.target.pointer_width {
             16 => InlineAsmType::I16,
             32 => InlineAsmType::I32,
@@ -65,64 +72,62 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
         };
 
         match *ty.kind() {
-            ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Some(InlineAsmType::I8),
+            ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Ok(InlineAsmType::I8),
-            ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => Some(InlineAsmType::I16),
+            ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => Ok(InlineAsmType::I16),
-            ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => Some(InlineAsmType::I32),
+            ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => Ok(InlineAsmType::I32),
-            ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => Some(InlineAsmType::I64),
+            ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => Ok(InlineAsmType::I64),
-            ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => Some(InlineAsmType::I128),
+            ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => Ok(InlineAsmType::I128),
-            ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => Some(asm_ty_isize),
+            ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => Ok(asm_ty_isize),
-            ty::Float(FloatTy::F16) => Some(InlineAsmType::F16),
+            ty::Float(FloatTy::F16) => Ok(InlineAsmType::F16),
-            ty::Float(FloatTy::F32) => Some(InlineAsmType::F32),
+            ty::Float(FloatTy::F32) => Ok(InlineAsmType::F32),
-            ty::Float(FloatTy::F64) => Some(InlineAsmType::F64),
+            ty::Float(FloatTy::F64) => Ok(InlineAsmType::F64),
-            ty::Float(FloatTy::F128) => Some(InlineAsmType::F128),
+            ty::Float(FloatTy::F128) => Ok(InlineAsmType::F128),
-            ty::FnPtr(..) => Some(asm_ty_isize),
+            ty::FnPtr(..) => Ok(asm_ty_isize),
-            ty::RawPtr(ty, _) if self.is_thin_ptr_ty(ty) => Some(asm_ty_isize),
+            ty::RawPtr(ty, _) if self.is_thin_ptr_ty(ty) => Ok(asm_ty_isize),
             ty::Adt(adt, args) if adt.repr().simd() => {
                 let fields = &adt.non_enum_variant().fields;
-                let elem_ty = fields[FieldIdx::ZERO].ty(self.tcx, args);
+                let field = &fields[FieldIdx::ZERO];
+                let elem_ty = field.ty(self.tcx, args);
 
                 let (size, ty) = match elem_ty.kind() {
                     ty::Array(ty, len) => {
+                        let len = self.tcx.normalize_erasing_regions(self.typing_env, *len);
                         if let Some(len) = len.try_to_target_usize(self.tcx) {
                             (len, *ty)
                         } else {
-                            return None;
+                            return Err(NonAsmTypeReason::UnevaluatedSIMDArrayLength(
+                                field.did, len,
+                            ));
                         }
                     }
                     _ => (fields.len() as u64, elem_ty),
                 };
 
                 match ty.kind() {
-                    ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Some(InlineAsmType::VecI8(size)),
+                    ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Ok(InlineAsmType::VecI8(size)),
-                    ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => {
+                    ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => Ok(InlineAsmType::VecI16(size)),
-                        Some(InlineAsmType::VecI16(size))
+                    ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => Ok(InlineAsmType::VecI32(size)),
-                    }
+                    ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => Ok(InlineAsmType::VecI64(size)),
-                    ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => {
-                        Some(InlineAsmType::VecI32(size))
-                    }
-                    ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => {
-                        Some(InlineAsmType::VecI64(size))
-                    }
                     ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => {
-                        Some(InlineAsmType::VecI128(size))
+                        Ok(InlineAsmType::VecI128(size))
                     }
                     ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => {
-                        Some(match self.tcx.sess.target.pointer_width {
+                        Ok(match self.tcx.sess.target.pointer_width {
                             16 => InlineAsmType::VecI16(size),
                             32 => InlineAsmType::VecI32(size),
                             64 => InlineAsmType::VecI64(size),
                             width => bug!("unsupported pointer width: {width}"),
                         })
                     }
-                    ty::Float(FloatTy::F16) => Some(InlineAsmType::VecF16(size)),
+                    ty::Float(FloatTy::F16) => Ok(InlineAsmType::VecF16(size)),
-                    ty::Float(FloatTy::F32) => Some(InlineAsmType::VecF32(size)),
+                    ty::Float(FloatTy::F32) => Ok(InlineAsmType::VecF32(size)),
-                    ty::Float(FloatTy::F64) => Some(InlineAsmType::VecF64(size)),
+                    ty::Float(FloatTy::F64) => Ok(InlineAsmType::VecF64(size)),
-                    ty::Float(FloatTy::F128) => Some(InlineAsmType::VecF128(size)),
+                    ty::Float(FloatTy::F128) => Ok(InlineAsmType::VecF128(size)),
-                    _ => None,
+                    _ => Err(NonAsmTypeReason::InvalidElement(field.did, ty)),
                 }
             }
             ty::Infer(_) => bug!("unexpected infer ty in asm operand"),
-            _ => None,
+            _ => Err(NonAsmTypeReason::Invalid(ty)),
         }
     }
 
@@ -163,17 +168,42 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
             }
             _ => self.get_asm_ty(ty),
         };
-        let Some(asm_ty) = asm_ty else {
+        let asm_ty = match asm_ty {
-            let msg = format!("cannot use value of type `{ty}` for inline assembly");
+            Ok(asm_ty) => asm_ty,
-            self.tcx
+            Err(reason) => {
-                .dcx()
+                match reason {
-                .struct_span_err(expr.span, msg)
+                    NonAsmTypeReason::UnevaluatedSIMDArrayLength(did, len) => {
-                .with_note(
+                        let msg = format!("cannot evaluate SIMD vector length `{len}`");
-                    "only integers, floats, SIMD vectors, pointers and function pointers \
+                        self.tcx
-                     can be used as arguments for inline assembly",
+                            .dcx()
-                )
+                            .struct_span_err(self.tcx.def_span(did), msg)
-                .emit();
+                            .with_span_note(
-            return None;
+                                expr.span,
+                                "SIMD vector length needs to be known statically for use in `asm!`",
+                            )
+                            .emit();
+                    }
+                    NonAsmTypeReason::Invalid(ty) => {
+                        let msg = format!("cannot use value of type `{ty}` for inline assembly");
+                        self.tcx.dcx().struct_span_err(expr.span, msg).with_note(
+                            "only integers, floats, SIMD vectors, pointers and function pointers \
+                            can be used as arguments for inline assembly",
+                        ).emit();
+                    }
+                    NonAsmTypeReason::InvalidElement(did, ty) => {
+                        let msg = format!(
+                            "cannot use SIMD vector with element type `{ty}` for inline assembly"
+                        );
+                        self.tcx.dcx()
+                        .struct_span_err(self.tcx.def_span(did), msg).with_span_note(
+                            expr.span,
+                            "only integers, floats, SIMD vectors, pointers and function pointers \
+                            can be used as arguments for inline assembly",
+                        ).emit();
+                    }
+                }
+                return None;
+            }
         };
 
         // Check that the type implements Copy. The only case where this can

compiler/rustc_hir_typeck/src/expr.rs

@@ -3076,7 +3076,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             err.help("methods are immutable and cannot be assigned to");
         }
 
-        err.emit()
+        // See `StashKey::GenericInFieldExpr` for more info
+        self.dcx().try_steal_replace_and_emit_err(field.span, StashKey::GenericInFieldExpr, err)
     }
 
     fn point_at_param_definition(&self, err: &mut Diag<'_>, param: ty::ParamTy) {

compiler/rustc_hir_typeck/src/fallback.rs

@@ -613,19 +613,16 @@ impl<'tcx> AnnotateUnitFallbackVisitor<'_, 'tcx> {
         if arg_segment.args.is_none()
             && let Some(all_args) = self.fcx.typeck_results.borrow().node_args_opt(id)
             && let generics = self.fcx.tcx.generics_of(def_id)
-            && let args = &all_args[generics.parent_count..]
+            && let args = all_args[generics.parent_count..].iter().zip(&generics.own_params)
             // We can't turbofish consts :(
-            && args.iter().all(|arg| matches!(arg.unpack(), ty::GenericArgKind::Type(_) | ty::GenericArgKind::Lifetime(_)))
+            && args.clone().all(|(_, param)| matches!(param.kind, ty::GenericParamDefKind::Type { .. } | ty::GenericParamDefKind::Lifetime))
         {
-            let n_tys = args
+            // We filter out APITs, which are not turbofished.
-                .iter()
+            let non_apit_type_args = args.filter(|(_, param)| {
-                .filter(|arg| matches!(arg.unpack(), ty::GenericArgKind::Type(_)))
+                matches!(param.kind, ty::GenericParamDefKind::Type { synthetic: false, .. })
-                .count();
+            });
-            for (idx, arg) in args
+            let n_tys = non_apit_type_args.clone().count();
-                .iter()
+            for (idx, (arg, _)) in non_apit_type_args.enumerate() {
-                .filter(|arg| matches!(arg.unpack(), ty::GenericArgKind::Type(_)))
-                .enumerate()
-            {
                 if let Some(ty) = arg.as_type()
                     && let Some(vid) = self.fcx.root_vid(ty)
                     && self.reachable_vids.contains(&vid)

compiler/rustc_lint/src/tests.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
+
 use rustc_span::{Symbol, create_default_session_globals_then};
 
 use crate::levels::parse_lint_and_tool_name;

compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs

@@ -4,52 +4,26 @@
 //! field-deref on a local variable, `x.field`, has the same meaning
 //! in both domains). Indexed projections are the exception: `a[x]`
 //! needs to be treated as mapping to the same move path as `a[y]` as
-//! well as `a[13]`, etc.
+//! well as `a[13]`, etc. So we map these `x`/`y` values to `()`.
 //!
 //! (In theory, the analysis could be extended to work with sets of
 //! paths, so that `a[0]` and `a[13]` could be kept distinct, while
 //! `a[x]` would still overlap them both. But that is not this
 //! representation does today.)
 
-use rustc_middle::mir::{Local, Operand, PlaceElem, ProjectionElem};
+use rustc_middle::mir::{PlaceElem, ProjectionElem, ProjectionKind};
-use rustc_middle::ty::Ty;
-
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-pub(crate) struct AbstractOperand;
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-pub(crate) struct AbstractType;
-pub(crate) type AbstractElem = ProjectionElem<AbstractOperand, AbstractType>;
 
 pub(crate) trait Lift {
-    type Abstract;
+    fn lift(&self) -> ProjectionKind;
-    fn lift(&self) -> Self::Abstract;
-}
-impl<'tcx> Lift for Operand<'tcx> {
-    type Abstract = AbstractOperand;
-    fn lift(&self) -> Self::Abstract {
-        AbstractOperand
-    }
-}
-impl Lift for Local {
-    type Abstract = AbstractOperand;
-    fn lift(&self) -> Self::Abstract {
-        AbstractOperand
-    }
-}
-impl<'tcx> Lift for Ty<'tcx> {
-    type Abstract = AbstractType;
-    fn lift(&self) -> Self::Abstract {
-        AbstractType
-    }
 }
+
 impl<'tcx> Lift for PlaceElem<'tcx> {
-    type Abstract = AbstractElem;
+    fn lift(&self) -> ProjectionKind {
-    fn lift(&self) -> Self::Abstract {
         match *self {
             ProjectionElem::Deref => ProjectionElem::Deref,
-            ProjectionElem::Field(f, ty) => ProjectionElem::Field(f, ty.lift()),
+            ProjectionElem::Field(f, _ty) => ProjectionElem::Field(f, ()),
-            ProjectionElem::OpaqueCast(ty) => ProjectionElem::OpaqueCast(ty.lift()),
+            ProjectionElem::OpaqueCast(_ty) => ProjectionElem::OpaqueCast(()),
-            ProjectionElem::Index(ref i) => ProjectionElem::Index(i.lift()),
+            ProjectionElem::Index(_i) => ProjectionElem::Index(()),
             ProjectionElem::Subslice { from, to, from_end } => {
                 ProjectionElem::Subslice { from, to, from_end }
             }
@@ -57,7 +31,7 @@ impl<'tcx> Lift for PlaceElem<'tcx> {
                 ProjectionElem::ConstantIndex { offset, min_length, from_end }
             }
             ProjectionElem::Downcast(a, u) => ProjectionElem::Downcast(a, u),
-            ProjectionElem::Subtype(ty) => ProjectionElem::Subtype(ty.lift()),
+            ProjectionElem::Subtype(_ty) => ProjectionElem::Subtype(()),
         }
     }
 }

compiler/rustc_mir_dataflow/src/move_paths/mod.rs

@@ -8,7 +8,7 @@ use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_span::Span;
 use smallvec::SmallVec;
 
-use self::abs_domain::{AbstractElem, Lift};
+use self::abs_domain::Lift;
 use crate::un_derefer::UnDerefer;
 
 mod abs_domain;
@@ -300,7 +300,7 @@ pub struct MovePathLookup<'tcx> {
     /// subsequent search so that it is solely relative to that
     /// base-place). For the remaining lookup, we map the projection
     /// elem to the associated MovePathIndex.
-    projections: FxHashMap<(MovePathIndex, AbstractElem), MovePathIndex>,
+    projections: FxHashMap<(MovePathIndex, ProjectionKind), MovePathIndex>,
 
     un_derefer: UnDerefer<'tcx>,
 }

compiler/rustc_parse/src/lexer/tokentrees.rs

@@ -1,7 +1,7 @@
 use rustc_ast::token::{self, Delimiter, Token};
 use rustc_ast::tokenstream::{DelimSpacing, DelimSpan, Spacing, TokenStream, TokenTree};
 use rustc_ast_pretty::pprust::token_to_string;
-use rustc_errors::{Applicability, PErr};
+use rustc_errors::{Applicability, Diag};
 use rustc_span::symbol::kw;
 
 use super::diagnostics::{report_suspicious_mismatch_block, same_indentation_level};
@@ -14,7 +14,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
     pub(super) fn lex_token_trees(
         &mut self,
         is_delimited: bool,
-    ) -> (Spacing, TokenStream, Result<(), Vec<PErr<'psess>>>) {
+    ) -> (Spacing, TokenStream, Result<(), Vec<Diag<'psess>>>) {
         // Move past the opening delimiter.
         let open_spacing = self.bump_minimal();
 
@@ -56,7 +56,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
         }
     }
 
-    fn eof_err(&mut self) -> PErr<'psess> {
+    fn eof_err(&mut self) -> Diag<'psess> {
         let msg = "this file contains an unclosed delimiter";
         let mut err = self.dcx().struct_span_err(self.token.span, msg);
 
@@ -98,7 +98,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
     fn lex_token_tree_open_delim(
         &mut self,
         open_delim: Delimiter,
-    ) -> Result<TokenTree, Vec<PErr<'psess>>> {
+    ) -> Result<TokenTree, Vec<Diag<'psess>>> {
         // The span for beginning of the delimited section.
         let pre_span = self.token.span;
 
@@ -250,8 +250,8 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
     fn unclosed_delim_err(
         &mut self,
         tts: TokenStream,
-        mut errs: Vec<PErr<'psess>>,
+        mut errs: Vec<Diag<'psess>>,
-    ) -> Vec<PErr<'psess>> {
+    ) -> Vec<Diag<'psess>> {
         // If there are unclosed delims, see if there are diff markers and if so, point them
         // out instead of complaining about the unclosed delims.
         let mut parser = Parser::new(self.psess, tts, None);
@@ -308,7 +308,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
         errs
     }
 
-    fn close_delim_err(&mut self, delim: Delimiter) -> PErr<'psess> {
+    fn close_delim_err(&mut self, delim: Delimiter) -> Diag<'psess> {
         // An unexpected closing delimiter (i.e., there is no matching opening delimiter).
         let token_str = token_to_string(&self.token);
         let msg = format!("unexpected closing delimiter: `{token_str}`");

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -16,7 +16,7 @@ use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{
-    Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, FatalError, PErr, PResult, Subdiagnostic,
+    Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, FatalError, PResult, Subdiagnostic,
     Suggestions, pluralize,
 };
 use rustc_session::errors::ExprParenthesesNeeded;
@@ -2132,7 +2132,7 @@ impl<'a> Parser<'a> {
         &mut self,
         delim: Delimiter,
         lo: Span,
-        err: PErr<'a>,
+        err: Diag<'a>,
     ) -> P<Expr> {
         let guar = err.emit();
         // Recover from parse error, callers expect the closing delim to be consumed.
@@ -3014,7 +3014,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Check for exclusive ranges written as `..<`
-    pub(crate) fn maybe_err_dotdotlt_syntax(&self, maybe_lt: Token, mut err: PErr<'a>) -> PErr<'a> {
+    pub(crate) fn maybe_err_dotdotlt_syntax(&self, maybe_lt: Token, mut err: Diag<'a>) -> Diag<'a> {
         if maybe_lt == token::Lt
             && (self.expected_tokens.contains(&TokenType::Token(token::Gt))
                 || matches!(self.token.kind, token::Literal(..)))

compiler/rustc_parse/src/parser/expr.rs

@@ -1369,11 +1369,14 @@ impl<'a> Parser<'a> {
             ))
         } else {
             // Field access `expr.f`
+            let span = lo.to(self.prev_token.span);
             if let Some(args) = seg.args {
-                self.dcx().emit_err(errors::FieldExpressionWithGeneric(args.span()));
+                // See `StashKey::GenericInFieldExpr` for more info on why we stash this.
+                self.dcx()
+                    .create_err(errors::FieldExpressionWithGeneric(args.span()))
+                    .stash(seg.ident.span, StashKey::GenericInFieldExpr);
             }
 
-            let span = lo.to(self.prev_token.span);
             Ok(self.mk_expr(span, ExprKind::Field(self_arg, seg.ident)))
         }
     }

compiler/rustc_parse/src/parser/tests.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
+
 use std::assert_matches::assert_matches;
 use std::io::prelude::*;
 use std::iter::Peekable;

compiler/rustc_parse/src/parser/tokenstream/tests.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
+
 use rustc_ast::token::{self, IdentIsRaw};
 use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_span::{BytePos, Span, Symbol, create_default_session_globals_then};

compiler/rustc_span/src/edit_distance/tests.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
+
 use super::*;
 
 #[test]

compiler/rustc_target/src/spec/base/windows_gnullvm.rs

@@ -42,6 +42,8 @@ pub(crate) fn opts() -> TargetOptions {
         eh_frame_header: false,
         no_default_libraries: false,
         has_thread_local: true,
+        crt_static_allows_dylibs: true,
+        crt_static_respected: true,
         // FIXME(davidtwco): Support Split DWARF on Windows GNU - may require LLVM changes to
         // output DWO, despite using DWARF, doesn't use ELF..
         debuginfo_kind: DebuginfoKind::Pdb,

library/alloc/src/alloc.rs

@@ -10,9 +10,6 @@ use core::hint;
 #[cfg(not(test))]
 use core::ptr::{self, NonNull};
 
-#[cfg(test)]
-mod tests;
-
 extern "Rust" {
     // These are the magic symbols to call the global allocator. rustc generates
     // them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute

library/alloc/src/collections/binary_heap/mod.rs

@@ -155,9 +155,6 @@ use crate::collections::TryReserveError;
 use crate::slice;
 use crate::vec::{self, AsVecIntoIter, Vec};
 
-#[cfg(test)]
-mod tests;
-
 /// A priority queue implemented with a binary heap.
 ///
 /// This will be a max-heap.

library/alloc/src/ffi/c_str.rs

@@ -1,8 +1,5 @@
 //! [`CString`] and its related types.
 
-#[cfg(test)]
-mod tests;
-
 use core::borrow::Borrow;
 use core::ffi::{CStr, c_char};
 use core::num::NonZero;

library/alloc/src/lib.rs

@@ -239,8 +239,6 @@ pub mod string;
 pub mod sync;
 #[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync)))]
 pub mod task;
-#[cfg(test)]
-mod tests;
 pub mod vec;
 
 #[doc(hidden)]

library/alloc/src/sync.rs

@@ -39,9 +39,6 @@ use crate::string::String;
 #[cfg(not(no_global_oom_handling))]
 use crate::vec::Vec;
 
-#[cfg(test)]
-mod tests;
-
 /// A soft limit on the amount of references that may be made to an `Arc`.
 ///
 /// Going above this limit will abort your program (although not

library/alloc/tests/alloc.rs

@@ -1,10 +1,9 @@
-use super::*;
+use alloc::alloc::*;
+use alloc::boxed::Box;
 
 extern crate test;
 use test::Bencher;
 
-use crate::boxed::Box;
-
 #[test]
 fn allocate_zeroed() {
     unsafe {

library/alloc/tests/c_str2.rs

@@ -1,11 +1,12 @@
+use alloc::ffi::CString;
+use alloc::rc::Rc;
+use alloc::sync::Arc;
 use core::assert_matches::assert_matches;
-use core::ffi::FromBytesUntilNulError;
+use core::ffi::{CStr, FromBytesUntilNulError, c_char};
 #[allow(deprecated)]
 use core::hash::SipHasher13 as DefaultHasher;
 use core::hash::{Hash, Hasher};
 
-use super::*;
-
 #[test]
 fn c_to_rust() {
     let data = b"123\0";

library/alloc/tests/collections/binary_heap.rs

@@ -1,7 +1,9 @@
+use alloc::boxed::Box;
+use alloc::collections::binary_heap::*;
+use std::iter::TrustedLen;
+use std::mem;
 use std::panic::{AssertUnwindSafe, catch_unwind};
 
-use super::*;
-use crate::boxed::Box;
 use crate::testing::crash_test::{CrashTestDummy, Panic};
 
 #[test]
@@ -531,7 +533,7 @@ fn panic_safe() {
             self.0.partial_cmp(&other.0)
         }
     }
-    let mut rng = crate::test_helpers::test_rng();
+    let mut rng = crate::test_rng();
     const DATASZ: usize = 32;
     // Miri is too slow
     let ntest = if cfg!(miri) { 1 } else { 10 };

library/alloc/tests/collections/mod.rs

@@ -0,0 +1 @@
+mod binary_heap;

library/alloc/tests/lib.rs

@@ -5,8 +5,10 @@
 #![feature(btree_extract_if)]
 #![feature(cow_is_borrowed)]
 #![feature(core_intrinsics)]
+#![feature(downcast_unchecked)]
 #![feature(extract_if)]
 #![feature(exact_size_is_empty)]
+#![feature(hashmap_internals)]
 #![feature(linked_list_cursors)]
 #![feature(map_try_insert)]
 #![feature(pattern)]
@@ -29,9 +31,11 @@
 #![feature(const_str_from_utf8)]
 #![feature(panic_update_hook)]
 #![feature(pointer_is_aligned_to)]
+#![feature(test)]
 #![feature(thin_box)]
 #![feature(drain_keep_rest)]
 #![feature(local_waker)]
+#![feature(str_as_str)]
 #![feature(strict_provenance_lints)]
 #![feature(vec_pop_if)]
 #![feature(unique_rc_arc)]
@@ -40,25 +44,33 @@
 #![deny(fuzzy_provenance_casts)]
 #![deny(unsafe_op_in_unsafe_fn)]
 
+extern crate test;
+
 use std::hash::{DefaultHasher, Hash, Hasher};
 
+mod alloc;
 mod arc;
 mod autotraits;
 mod borrow;
 mod boxed;
 mod btree_set_hash;
 mod c_str;
+mod c_str2;
+mod collections;
 mod const_fns;
 mod cow_str;
 mod fmt;
 mod heap;
 mod linked_list;
+mod misc_tests;
 mod rc;
 mod slice;
 mod sort;
 mod str;
 mod string;
+mod sync;
 mod task;
+mod testing;
 mod thin_box;
 mod vec;
 mod vec_deque;
@@ -69,6 +81,18 @@ fn hash<T: Hash>(t: &T) -> u64 {
     s.finish()
 }
 
+/// Copied from `std::test_helpers::test_rng`, since these tests rely on the
+/// seed not being the same for every RNG invocation too.
+fn test_rng() -> rand_xorshift::XorShiftRng {
+    use std::hash::{BuildHasher, Hash, Hasher};
+    let mut hasher = std::hash::RandomState::new().build_hasher();
+    std::panic::Location::caller().hash(&mut hasher);
+    let hc64 = hasher.finish();
+    let seed_vec = hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<Vec<u8>>();
+    let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
+    rand::SeedableRng::from_seed(seed)
+}
+
 // FIXME: Instantiated functions with i128 in the signature is not supported in Emscripten.
 // See https://github.com/kripken/emscripten-fastcomp/issues/169
 #[cfg(not(target_os = "emscripten"))]

library/alloc/tests/sync.rs

@@ -1,14 +1,16 @@
+use alloc::sync::*;
+use std::alloc::{AllocError, Allocator, Layout};
+use std::any::Any;
 use std::clone::Clone;
 use std::mem::MaybeUninit;
 use std::option::Option::None;
+use std::ptr::NonNull;
 use std::sync::Mutex;
-use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::*;
-use std::sync::atomic::Ordering::SeqCst;
+use std::sync::atomic::{self, AtomicUsize};
 use std::sync::mpsc::channel;
 use std::thread;
 
-use super::*;
-
 struct Canary(*mut AtomicUsize);
 
 impl Drop for Canary {

library/alloc/tests/testing/crash_test.rs

@@ -0,0 +1,80 @@
+use std::cmp::Ordering;
+use std::fmt::Debug;
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::SeqCst;
+
+/// A blueprint for crash test dummy instances that monitor drops.
+/// Some instances may be configured to panic at some point.
+///
+/// Crash test dummies are identified and ordered by an id, so they can be used
+/// as keys in a BTreeMap.
+#[derive(Debug)]
+pub struct CrashTestDummy {
+    pub id: usize,
+    dropped: AtomicUsize,
+}
+
+impl CrashTestDummy {
+    /// Creates a crash test dummy design. The `id` determines order and equality of instances.
+    pub fn new(id: usize) -> CrashTestDummy {
+        CrashTestDummy { id, dropped: AtomicUsize::new(0) }
+    }
+
+    /// Creates an instance of a crash test dummy that records what events it experiences
+    /// and optionally panics.
+    pub fn spawn(&self, panic: Panic) -> Instance<'_> {
+        Instance { origin: self, panic }
+    }
+
+    /// Returns how many times instances of the dummy have been dropped.
+    pub fn dropped(&self) -> usize {
+        self.dropped.load(SeqCst)
+    }
+}
+
+#[derive(Debug)]
+pub struct Instance<'a> {
+    origin: &'a CrashTestDummy,
+    panic: Panic,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum Panic {
+    Never,
+    InDrop,
+}
+
+impl Instance<'_> {
+    pub fn id(&self) -> usize {
+        self.origin.id
+    }
+}
+
+impl Drop for Instance<'_> {
+    fn drop(&mut self) {
+        self.origin.dropped.fetch_add(1, SeqCst);
+        if self.panic == Panic::InDrop {
+            panic!("panic in `drop`");
+        }
+    }
+}
+
+impl PartialOrd for Instance<'_> {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        self.id().partial_cmp(&other.id())
+    }
+}
+
+impl Ord for Instance<'_> {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.id().cmp(&other.id())
+    }
+}
+
+impl PartialEq for Instance<'_> {
+    fn eq(&self, other: &Self) -> bool {
+        self.id().eq(&other.id())
+    }
+}
+
+impl Eq for Instance<'_> {}

library/alloc/tests/testing/mod.rs

@@ -0,0 +1 @@
+pub mod crash_test;

library/core/src/prelude/mod.rs

@@ -71,7 +71,7 @@ pub mod rust_2021 {
 /// The 2024 version of the core prelude.
 ///
 /// See the [module-level documentation](self) for more.
-#[unstable(feature = "prelude_2024", issue = "121042")]
+#[stable(feature = "prelude_2024", since = "CURRENT_RUSTC_VERSION")]
 pub mod rust_2024 {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub use super::common::*;
@@ -84,7 +84,7 @@ pub mod rust_2024 {
     #[doc(no_inline)]
     pub use crate::convert::{TryFrom, TryInto};
 
-    #[unstable(feature = "prelude_2024", issue = "121042")]
+    #[stable(feature = "prelude_2024", since = "CURRENT_RUSTC_VERSION")]
     #[doc(no_inline)]
     pub use crate::future::{Future, IntoFuture};
 }

library/core/src/ptr/mut_ptr.rs

@@ -1587,15 +1587,6 @@ impl<T: ?Sized> *mut T {
     /// beyond the allocation that the pointer points into. It is up to the caller to ensure that
     /// the returned offset is correct in all terms other than alignment.
     ///
-    /// When this is called during compile-time evaluation (which is unstable), the implementation
-    /// may return `usize::MAX` in cases where that can never happen at runtime. This is because the
-    /// actual alignment of pointers is not known yet during compile-time, so an offset with
-    /// guaranteed alignment can sometimes not be computed. For example, a buffer declared as `[u8;
-    /// N]` might be allocated at an odd or an even address, but at compile-time this is not yet
-    /// known, so the execution has to be correct for either choice. It is therefore impossible to
-    /// find an offset that is guaranteed to be 2-aligned. (This behavior is subject to change, as usual
-    /// for unstable APIs.)
-    ///
     /// # Panics
     ///
     /// The function panics if `align` is not a power-of-two.

library/std/src/lib.rs

@@ -348,7 +348,6 @@
 #![feature(pin_coerce_unsized_trait)]
 #![feature(pointer_is_aligned_to)]
 #![feature(portable_simd)]
-#![feature(prelude_2024)]
 #![feature(ptr_as_uninit)]
 #![feature(ptr_mask)]
 #![feature(random)]

library/std/src/os/hurd/mod.rs

@@ -1,6 +1,7 @@
 //! Hurd-specific definitions
 
 #![stable(feature = "raw_ext", since = "1.1.0")]
+#![forbid(unsafe_op_in_unsafe_fn)]
 
 pub mod fs;
 pub mod raw;

library/std/src/prelude/mod.rs

@@ -25,6 +25,7 @@
 //!
 //! # Prelude contents
 //!
+//! The items included in the prelude depend on the edition of the crate.
 //! The first version of the prelude is used in Rust 2015 and Rust 2018,
 //! and lives in [`std::prelude::v1`].
 //! [`std::prelude::rust_2015`] and [`std::prelude::rust_2018`] re-export this prelude.
@@ -67,15 +68,21 @@
 //! The prelude used in Rust 2021, [`std::prelude::rust_2021`], includes all of the above,
 //! and in addition re-exports:
 //!
-//! * <code>[std::convert]::{[TryFrom], [TryInto]}</code>,
+//! * <code>[std::convert]::{[TryFrom], [TryInto]}</code>.
 //! * <code>[std::iter]::[FromIterator]</code>.
 //!
+//! The prelude used in Rust 2024, [`std::prelude::rust_2024`], includes all of the above,
+//! and in addition re-exports:
+//!
+//! * <code>[std::future]::{[Future], [IntoFuture]}</code>.
+//!
 //! [std::borrow]: crate::borrow
 //! [std::boxed]: crate::boxed
 //! [std::clone]: crate::clone
 //! [std::cmp]: crate::cmp
 //! [std::convert]: crate::convert
 //! [std::default]: crate::default
+//! [std::future]: crate::future
 //! [std::iter]: crate::iter
 //! [std::marker]: crate::marker
 //! [std::mem]: crate::mem
@@ -85,6 +92,7 @@
 //! [`std::prelude::rust_2015`]: rust_2015
 //! [`std::prelude::rust_2018`]: rust_2018
 //! [`std::prelude::rust_2021`]: rust_2021
+//! [`std::prelude::rust_2024`]: rust_2024
 //! [std::result]: crate::result
 //! [std::slice]: crate::slice
 //! [std::string]: crate::string
@@ -94,6 +102,8 @@
 //! [book-dtor]: ../../book/ch15-03-drop.html
 //! [book-enums]: ../../book/ch06-01-defining-an-enum.html
 //! [book-iter]: ../../book/ch13-02-iterators.html
+//! [Future]: crate::future::Future
+//! [IntoFuture]: crate::future::IntoFuture
 
 // No formatting: this file is nothing but re-exports, and their order is worth preserving.
 #![cfg_attr(rustfmt, rustfmt::skip)]
@@ -158,12 +168,12 @@ pub mod rust_2021 {
 /// The 2024 version of the prelude of The Rust Standard Library.
 ///
 /// See the [module-level documentation](self) for more.
-#[unstable(feature = "prelude_2024", issue = "121042")]
+#[stable(feature = "prelude_2024", since = "CURRENT_RUSTC_VERSION")]
 pub mod rust_2024 {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub use super::common::*;
 
-    #[unstable(feature = "prelude_2024", issue = "121042")]
+    #[stable(feature = "prelude_2024", since = "CURRENT_RUSTC_VERSION")]
     #[doc(no_inline)]
     pub use core::prelude::rust_2024::*;
 }

library/unwind/src/lib.rs

@@ -178,3 +178,8 @@ cfg_if::cfg_if! {
 #[cfg(target_os = "hurd")]
 #[link(name = "gcc_s")]
 extern "C" {}
+
+#[cfg(all(target_os = "windows", target_env = "gnu", target_abi = "llvm"))]
+#[link(name = "unwind", kind = "static", modifiers = "-bundle", cfg(target_feature = "crt-static"))]
+#[link(name = "unwind", cfg(not(target_feature = "crt-static")))]
+extern "C" {}

library/unwind/src/libunwind.rs

@@ -102,12 +102,9 @@ pub type _Unwind_Exception_Cleanup_Fn =
 // rustc_codegen_ssa::src::back::symbol_export, rustc_middle::middle::exported_symbols
 // and RFC 2841
 #[cfg_attr(
-    any(
+    all(
-        all(
+        feature = "llvm-libunwind",
-            feature = "llvm-libunwind",
+        any(target_os = "fuchsia", target_os = "linux", target_os = "xous")
-            any(target_os = "fuchsia", target_os = "linux", target_os = "xous")
-        ),
-        all(target_os = "windows", target_env = "gnu", target_abi = "llvm")
     ),
     link(name = "unwind", kind = "static", modifiers = "-bundle")
 )]

src/bootstrap/src/core/builder/cargo.rs

@@ -1035,12 +1035,7 @@ impl Builder<'_> {
             rustflags.arg("-Wrustc::internal");
             // cfg(bootstrap) - remove this check when lint is in bootstrap compiler
             if stage != 0 {
-                // Lint is allow by default so downstream tools don't get a lit
+                rustflags.arg("-Drustc::symbol_intern_string_literal");
-                // they can do nothing about
-                // We shouldn't be preinterning symbols used by tests
-                if cmd_kind != Kind::Test {
-                    rustflags.arg("-Drustc::symbol_intern_string_literal");
-                }
             }
             // FIXME(edition_2024): Change this to `-Wrust_2024_idioms` when all
             // of the individual lints are satisfied.

tests/ui/asm/generic_const_simd_vec_len.rs

@@ -0,0 +1,21 @@
+//! This is a regression test to ensure that we emit a diagnostic pointing to the
+//! reason the type was rejected in inline assembly.
+
+//@ only-x86_64
+
+#![feature(repr_simd)]
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct Foo<const C: usize>([u8; C]);
+//~^ ERROR: cannot evaluate SIMD vector length
+
+pub unsafe fn foo<const C: usize>(a: Foo<C>) {
+    std::arch::asm!(
+        "movaps {src}, {src}",
+        src = in(xmm_reg) a,
+        //~^ NOTE: SIMD vector length needs to be known statically
+    );
+}
+
+fn main() {}

tests/ui/asm/generic_const_simd_vec_len.stderr

@@ -0,0 +1,14 @@
+error: cannot evaluate SIMD vector length `C`
+  --> $DIR/generic_const_simd_vec_len.rs:10:32
+   |
+LL | pub struct Foo<const C: usize>([u8; C]);
+   |                                ^^^^^^^
+   |
+note: SIMD vector length needs to be known statically for use in `asm!`
+  --> $DIR/generic_const_simd_vec_len.rs:16:27
+   |
+LL |         src = in(xmm_reg) a,
+   |                           ^
+
+error: aborting due to 1 previous error
+

tests/ui/asm/named_const_simd_vec_len.rs

@@ -0,0 +1,22 @@
+//! This is a regression test to ensure that we evaluate
+//! SIMD vector length constants instead of assuming they are literals.
+
+//@ only-x86_64
+//@ check-pass
+
+#![feature(repr_simd)]
+
+const C: usize = 16;
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct Foo([u8; C]);
+
+pub unsafe fn foo(a: Foo) {
+    std::arch::asm!(
+        "movaps {src}, {src}",
+        src = in(xmm_reg) a,
+    );
+}
+
+fn main() {}

tests/ui/editions/never-type-fallback-breaking.e2021.fixed

@@ -11,6 +11,8 @@ fn main() {
     m();
     q();
     let _ = meow();
+    let _ = fallback_return();
+    let _ = fully_apit();
 }
 
 fn m() {
@@ -49,3 +51,29 @@ fn meow() -> Result<(), ()> {
     //[e2024]~^ error: the trait bound `(): From<!>` is not satisfied
     Ok(())
 }
+
+pub fn takes_apit<T>(_y: impl Fn() -> T) -> Result<T, ()> {
+    Err(())
+}
+
+pub fn fallback_return() -> Result<(), ()> {
+    //[e2021]~^ this function depends on never type fallback being `()`
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+    takes_apit::<()>(|| Default::default())?;
+    //[e2024]~^ error: the trait bound `!: Default` is not satisfied
+    Ok(())
+}
+
+fn mk<T>() -> Result<T, ()> {
+    Err(())
+}
+
+fn takes_apit2(_x: impl Default) {}
+
+fn fully_apit() -> Result<(), ()> {
+    //[e2021]~^ this function depends on never type fallback being `()`
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+    takes_apit2(mk::<()>()?);
+    //[e2024]~^ error: the trait bound `!: Default` is not satisfied
+    Ok(())
+}

tests/ui/editions/never-type-fallback-breaking.e2021.stderr

@@ -1,5 +1,5 @@
 warning: this function depends on never type fallback being `()`
-  --> $DIR/never-type-fallback-breaking.rs:16:1
+  --> $DIR/never-type-fallback-breaking.rs:18:1
    |
 LL | fn m() {
    | ^^^^^^
@@ -8,7 +8,7 @@ LL | fn m() {
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Default` will fail
-  --> $DIR/never-type-fallback-breaking.rs:20:17
+  --> $DIR/never-type-fallback-breaking.rs:22:17
    |
 LL |         true => Default::default(),
    |                 ^^^^^^^^^^^^^^^^^^
@@ -19,7 +19,7 @@ LL |     let x: () = match true {
    |          ++++
 
 warning: this function depends on never type fallback being `()`
-  --> $DIR/never-type-fallback-breaking.rs:28:1
+  --> $DIR/never-type-fallback-breaking.rs:30:1
    |
 LL | fn q() -> Option<()> {
    | ^^^^^^^^^^^^^^^^^^^^
@@ -28,7 +28,7 @@ LL | fn q() -> Option<()> {
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Default` will fail
-  --> $DIR/never-type-fallback-breaking.rs:35:5
+  --> $DIR/never-type-fallback-breaking.rs:37:5
    |
 LL |     deserialize()?;
    |     ^^^^^^^^^^^^^
@@ -38,7 +38,7 @@ LL |     deserialize::<()>()?;
    |                ++++++
 
 warning: this function depends on never type fallback being `()`
-  --> $DIR/never-type-fallback-breaking.rs:45:1
+  --> $DIR/never-type-fallback-breaking.rs:47:1
    |
 LL | fn meow() -> Result<(), ()> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -47,7 +47,7 @@ LL | fn meow() -> Result<(), ()> {
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `(): From<!>` will fail
-  --> $DIR/never-type-fallback-breaking.rs:48:5
+  --> $DIR/never-type-fallback-breaking.rs:50:5
    |
 LL |     help(1)?;
    |     ^^^^^^^
@@ -56,5 +56,43 @@ help: use `()` annotations to avoid fallback changes
 LL |     help::<(), _>(1)?;
    |         +++++++++
 
-warning: 3 warnings emitted
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:59:1
+   |
+LL | pub fn fallback_return() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/never-type-fallback-breaking.rs:62:19
+   |
+LL |     takes_apit(|| Default::default())?;
+   |                   ^^^^^^^^^^^^^^^^^^
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     takes_apit::<()>(|| Default::default())?;
+   |               ++++++
+
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:73:1
+   |
+LL | fn fully_apit() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/never-type-fallback-breaking.rs:76:17
+   |
+LL |     takes_apit2(mk()?);
+   |                 ^^^^^
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     takes_apit2(mk::<()>()?);
+   |                   ++++++
+
+warning: 5 warnings emitted
 

tests/ui/editions/never-type-fallback-breaking.e2024.stderr

@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `!: Default` is not satisfied
-  --> $DIR/never-type-fallback-breaking.rs:20:17
+  --> $DIR/never-type-fallback-breaking.rs:22:17
    |
 LL |         true => Default::default(),
    |                 ^^^^^^^^^^^^^^^^^^ the trait `Default` is not implemented for `!`
@@ -8,7 +8,7 @@ LL |         true => Default::default(),
    = help: did you intend to use the type `()` here instead?
 
 error[E0277]: the trait bound `!: Default` is not satisfied
-  --> $DIR/never-type-fallback-breaking.rs:35:5
+  --> $DIR/never-type-fallback-breaking.rs:37:5
    |
 LL |     deserialize()?;
    |     ^^^^^^^^^^^^^ the trait `Default` is not implemented for `!`
@@ -16,13 +16,13 @@ LL |     deserialize()?;
    = note: this error might have been caused by changes to Rust's type-inference algorithm (see issue #48950 <https://github.com/rust-lang/rust/issues/48950> for more information)
    = help: did you intend to use the type `()` here instead?
 note: required by a bound in `deserialize`
-  --> $DIR/never-type-fallback-breaking.rs:31:23
+  --> $DIR/never-type-fallback-breaking.rs:33:23
    |
 LL |     fn deserialize<T: Default>() -> Option<T> {
    |                       ^^^^^^^ required by this bound in `deserialize`
 
 error[E0277]: the trait bound `(): From<!>` is not satisfied
-  --> $DIR/never-type-fallback-breaking.rs:48:5
+  --> $DIR/never-type-fallback-breaking.rs:50:5
    |
 LL |     help(1)?;
    |     ^^^^^^^ the trait `From<!>` is not implemented for `()`
@@ -39,11 +39,36 @@ LL |     help(1)?;
            and 4 others
    = note: required for `!` to implement `Into<()>`
 note: required by a bound in `help`
-  --> $DIR/never-type-fallback-breaking.rs:42:20
+  --> $DIR/never-type-fallback-breaking.rs:44:20
    |
 LL | fn help<'a: 'a, T: Into<()>, U>(_: U) -> Result<T, ()> {
    |                    ^^^^^^^^ required by this bound in `help`
 
-error: aborting due to 3 previous errors
+error[E0277]: the trait bound `!: Default` is not satisfied
+  --> $DIR/never-type-fallback-breaking.rs:62:19
+   |
+LL |     takes_apit(|| Default::default())?;
+   |                   ^^^^^^^^^^^^^^^^^^ the trait `Default` is not implemented for `!`
+   |
+   = note: this error might have been caused by changes to Rust's type-inference algorithm (see issue #48950 <https://github.com/rust-lang/rust/issues/48950> for more information)
+   = help: did you intend to use the type `()` here instead?
+
+error[E0277]: the trait bound `!: Default` is not satisfied
+  --> $DIR/never-type-fallback-breaking.rs:76:17
+   |
+LL |     takes_apit2(mk()?);
+   |     ----------- ^^^^^ the trait `Default` is not implemented for `!`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = note: this error might have been caused by changes to Rust's type-inference algorithm (see issue #48950 <https://github.com/rust-lang/rust/issues/48950> for more information)
+   = help: did you intend to use the type `()` here instead?
+note: required by a bound in `takes_apit2`
+  --> $DIR/never-type-fallback-breaking.rs:71:25
+   |
+LL | fn takes_apit2(_x: impl Default) {}
+   |                         ^^^^^^^ required by this bound in `takes_apit2`
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

tests/ui/editions/never-type-fallback-breaking.rs

@@ -11,6 +11,8 @@ fn main() {
     m();
     q();
     let _ = meow();
+    let _ = fallback_return();
+    let _ = fully_apit();
 }
 
 fn m() {
@@ -49,3 +51,29 @@ fn meow() -> Result<(), ()> {
     //[e2024]~^ error: the trait bound `(): From<!>` is not satisfied
     Ok(())
 }
+
+pub fn takes_apit<T>(_y: impl Fn() -> T) -> Result<T, ()> {
+    Err(())
+}
+
+pub fn fallback_return() -> Result<(), ()> {
+    //[e2021]~^ this function depends on never type fallback being `()`
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+    takes_apit(|| Default::default())?;
+    //[e2024]~^ error: the trait bound `!: Default` is not satisfied
+    Ok(())
+}
+
+fn mk<T>() -> Result<T, ()> {
+    Err(())
+}
+
+fn takes_apit2(_x: impl Default) {}
+
+fn fully_apit() -> Result<(), ()> {
+    //[e2021]~^ this function depends on never type fallback being `()`
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+    takes_apit2(mk()?);
+    //[e2024]~^ error: the trait bound `!: Default` is not satisfied
+    Ok(())
+}

tests/ui/never_type/fallback-closure-ret.nofallback.stderr

@@ -15,8 +15,8 @@ LL |     foo(|| panic!());
    = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
 help: use `()` annotations to avoid fallback changes
    |
-LL |     foo::<(), _>(|| panic!());
+LL |     foo::<()>(|| panic!());
-   |        +++++++++
+   |        ++++++
 
 warning: 1 warning emitted
 

tests/ui/parser/bad-name.stderr

@@ -1,9 +1,3 @@
-error: field expressions cannot have generic arguments
-  --> $DIR/bad-name.rs:2:12
-   |
-LL |   let x.y::<isize>.z foo;
-   |            ^^^^^^^
-
 error: expected a pattern, found an expression
   --> $DIR/bad-name.rs:2:7
    |
@@ -18,5 +12,11 @@ error: expected one of `(`, `.`, `::`, `:`, `;`, `=`, `?`, `|`, or an operator,
 LL |   let x.y::<isize>.z foo;
    |                      ^^^ expected one of 9 possible tokens
 
+error: field expressions cannot have generic arguments
+  --> $DIR/bad-name.rs:2:12
+   |
+LL |   let x.y::<isize>.z foo;
+   |            ^^^^^^^
+
 error: aborting due to 3 previous errors
 

tests/ui/suggestions/method-missing-parentheses.rs

@@ -1,5 +1,4 @@
 fn main() {
     let _ = vec![].into_iter().collect::<usize>;
     //~^ ERROR attempted to take value of method `collect` on type `std::vec::IntoIter<_>`
-    //~| ERROR field expressions cannot have generic arguments
 }

tests/ui/suggestions/method-missing-parentheses.stderr

@@ -1,9 +1,3 @@
-error: field expressions cannot have generic arguments
-  --> $DIR/method-missing-parentheses.rs:2:41
-   |
-LL |     let _ = vec![].into_iter().collect::<usize>;
-   |                                         ^^^^^^^
-
 error[E0615]: attempted to take value of method `collect` on type `std::vec::IntoIter<_>`
   --> $DIR/method-missing-parentheses.rs:2:32
    |
@@ -15,6 +9,6 @@ help: use parentheses to call the method
 LL |     let _ = vec![].into_iter().collect::<usize>();
    |                                                ++
 
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0615`.