Rollup of 7 pull requests

RELEASES.md

@@ -1,4 +1,4 @@
-Version 1.80 (2024-07-25)
+Version 1.80.0 (2024-07-25)
 ==========================
 
 <a id="1.80-Language"></a>

compiler/rustc_ast/src/ast.rs

@@ -36,6 +36,7 @@ use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{ErrorGuaranteed, Span, DUMMY_SP};
+use std::borrow::Cow;
 use std::cmp;
 use std::fmt;
 use std::mem;
@@ -2272,7 +2273,7 @@ impl std::fmt::Debug for InlineAsmOptions {
 
 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
 pub enum InlineAsmTemplatePiece {
-    String(String),
+    String(Cow<'static, str>),
     Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
 }
 

compiler/rustc_ast_lowering/src/item.rs

@@ -1525,8 +1525,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     continue;
                 }
                 let is_param = *is_param.get_or_insert_with(compute_is_param);
-                if !is_param {
-                    self.dcx().emit_err(MisplacedRelaxTraitBound { span: bound.span() });
+                if !is_param && !self.tcx.features().more_maybe_bounds {
+                    self.tcx
+                        .sess
+                        .create_feature_err(
+                            MisplacedRelaxTraitBound { span: bound.span() },
+                            sym::more_maybe_bounds,
+                        )
+                        .emit();
                 }
             }
         }

compiler/rustc_ast_lowering/src/lib.rs

@@ -1216,6 +1216,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     itctx,
                     TraitBoundModifiers::NONE,
                 );
+                let bound = (bound, hir::TraitBoundModifier::None);
                 let bounds = this.arena.alloc_from_iter([bound]);
                 let lifetime_bound = this.elided_dyn_bound(t.span);
                 (bounds, lifetime_bound)
@@ -1348,21 +1349,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             // We can safely ignore constness here since AST validation
                             // takes care of rejecting invalid modifier combinations and
                             // const trait bounds in trait object types.
-                            GenericBound::Trait(ty, modifiers) => match modifiers.polarity {
-                                BoundPolarity::Positive | BoundPolarity::Negative(_) => {
-                                    Some(this.lower_poly_trait_ref(
-                                        ty,
-                                        itctx,
-                                        // Still, don't pass along the constness here; we don't want to
-                                        // synthesize any host effect args, it'd only cause problems.
-                                        TraitBoundModifiers {
-                                            constness: BoundConstness::Never,
-                                            ..*modifiers
-                                        },
-                                    ))
-                                }
-                                BoundPolarity::Maybe(_) => None,
-                            },
+                            GenericBound::Trait(ty, modifiers) => {
+                                // Still, don't pass along the constness here; we don't want to
+                                // synthesize any host effect args, it'd only cause problems.
+                                let modifiers = TraitBoundModifiers {
+                                    constness: BoundConstness::Never,
+                                    ..*modifiers
+                                };
+                                let trait_ref = this.lower_poly_trait_ref(ty, itctx, modifiers);
+                                let polarity = this.lower_trait_bound_modifiers(modifiers);
+                                Some((trait_ref, polarity))
+                            }
                             GenericBound::Outlives(lifetime) => {
                                 if lifetime_bound.is_none() {
                                     lifetime_bound = Some(this.lower_lifetime(lifetime));
@@ -2688,6 +2685,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             trait_ref: hir::TraitRef { path, hir_ref_id: hir_id },
                             span: self.lower_span(span),
                         };
+                        let principal = (principal, hir::TraitBoundModifier::None);
 
                         // The original ID is taken by the `PolyTraitRef`,
                         // so the `Ty` itself needs a different one.

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1345,14 +1345,28 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
         match bound {
             GenericBound::Trait(trait_ref, modifiers) => {
                 match (ctxt, modifiers.constness, modifiers.polarity) {
-                    (BoundKind::SuperTraits, BoundConstness::Never, BoundPolarity::Maybe(_)) => {
-                        self.dcx().emit_err(errors::OptionalTraitSupertrait {
-                            span: trait_ref.span,
-                            path_str: pprust::path_to_string(&trait_ref.trait_ref.path),
-                        });
+                    (BoundKind::SuperTraits, BoundConstness::Never, BoundPolarity::Maybe(_))
+                        if !self.features.more_maybe_bounds =>
+                    {
+                        self.session
+                            .create_feature_err(
+                                errors::OptionalTraitSupertrait {
+                                    span: trait_ref.span,
+                                    path_str: pprust::path_to_string(&trait_ref.trait_ref.path),
+                                },
+                                sym::more_maybe_bounds,
+                            )
+                            .emit();
                     }
-                    (BoundKind::TraitObject, BoundConstness::Never, BoundPolarity::Maybe(_)) => {
-                        self.dcx().emit_err(errors::OptionalTraitObject { span: trait_ref.span });
+                    (BoundKind::TraitObject, BoundConstness::Never, BoundPolarity::Maybe(_))
+                        if !self.features.more_maybe_bounds =>
+                    {
+                        self.session
+                            .create_feature_err(
+                                errors::OptionalTraitObject { span: trait_ref.span },
+                                sym::more_maybe_bounds,
+                            )
+                            .emit();
                     }
                     (
                         BoundKind::TraitObject,

compiler/rustc_builtin_macros/src/asm.rs

@@ -459,7 +459,7 @@ fn expand_preparsed_asm(
 
     for (i, template_expr) in args.templates.into_iter().enumerate() {
         if i != 0 {
-            template.push(ast::InlineAsmTemplatePiece::String("\n".to_string()));
+            template.push(ast::InlineAsmTemplatePiece::String("\n".into()));
         }
 
         let msg = "asm template must be a string literal";
@@ -527,7 +527,7 @@ fn expand_preparsed_asm(
 
         // Don't treat raw asm as a format string.
         if args.options.contains(ast::InlineAsmOptions::RAW) {
-            template.push(ast::InlineAsmTemplatePiece::String(template_str.to_string()));
+            template.push(ast::InlineAsmTemplatePiece::String(template_str.to_string().into()));
             let template_num_lines = 1 + template_str.matches('\n').count();
             line_spans.extend(std::iter::repeat(template_sp).take(template_num_lines));
             continue;
@@ -577,7 +577,7 @@ fn expand_preparsed_asm(
         for piece in unverified_pieces {
             match piece {
                 parse::Piece::String(s) => {
-                    template.push(ast::InlineAsmTemplatePiece::String(s.to_string()))
+                    template.push(ast::InlineAsmTemplatePiece::String(s.to_string().into()))
                 }
                 parse::Piece::NextArgument(arg) => {
                     let span = arg_spans.next().unwrap_or(template_sp);

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -46,9 +46,7 @@ pub(crate) fn codegen_inline_asm_terminator<'tcx>(
     // Used by panic_abort on Windows, but uses a syntax which only happens to work with
     // asm!() by accident and breaks with the GNU assembler as well as global_asm!() for
     // the LLVM backend.
-    if template.len() == 1
-        && template[0] == InlineAsmTemplatePiece::String("int $$0x29".to_string())
-    {
+    if template.len() == 1 && template[0] == InlineAsmTemplatePiece::String("int $$0x29".into()) {
         fx.bcx.ins().trap(TrapCode::User(1));
         return;
     }

compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs

@@ -40,7 +40,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
                     shl rdx, 32
                     or rax, rdx
                     "
-                    .to_string(),
+                    .into(),
                 )],
                 &[
                     CInlineAsmOperand::In {
@@ -471,7 +471,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
             // into 0x80000000 for which Cranelift doesn't have a native instruction.
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(format!("cvtps2dq xmm0, xmm0"))],
+                &[InlineAsmTemplatePiece::String("cvtps2dq xmm0, xmm0".into())],
                 &[CInlineAsmOperand::InOut {
                     reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
                     _late: true,
@@ -875,7 +875,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(asm.to_string())],
+                &[InlineAsmTemplatePiece::String(asm.into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::ax)),
@@ -914,7 +914,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(format!("pcmpestri xmm0, xmm1, {imm8}"))],
+                &[InlineAsmTemplatePiece::String(format!("pcmpestri xmm0, xmm1, {imm8}").into())],
                 &[
                     CInlineAsmOperand::In {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -967,7 +967,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(format!("pcmpestrm xmm0, xmm1, {imm8}"))],
+                &[InlineAsmTemplatePiece::String(format!("pcmpestrm xmm0, xmm1, {imm8}").into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -1015,7 +1015,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(format!("pclmulqdq xmm0, xmm1, {imm8}"))],
+                &[InlineAsmTemplatePiece::String(format!("pclmulqdq xmm0, xmm1, {imm8}").into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -1052,7 +1052,9 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(format!("aeskeygenassist xmm0, xmm0, {imm8}"))],
+                &[InlineAsmTemplatePiece::String(
+                    format!("aeskeygenassist xmm0, xmm0, {imm8}").into(),
+                )],
                 &[CInlineAsmOperand::InOut {
                     reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
                     _late: true,
@@ -1071,7 +1073,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("aesimc xmm0, xmm0".to_string())],
+                &[InlineAsmTemplatePiece::String("aesimc xmm0, xmm0".into())],
                 &[CInlineAsmOperand::InOut {
                     reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
                     _late: true,
@@ -1091,7 +1093,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("aesenc xmm0, xmm1".to_string())],
+                &[InlineAsmTemplatePiece::String("aesenc xmm0, xmm1".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -1117,7 +1119,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("aesenclast xmm0, xmm1".to_string())],
+                &[InlineAsmTemplatePiece::String("aesenclast xmm0, xmm1".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -1143,7 +1145,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("aesdec xmm0, xmm1".to_string())],
+                &[InlineAsmTemplatePiece::String("aesdec xmm0, xmm1".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -1169,7 +1171,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("aesdeclast xmm0, xmm1".to_string())],
+                &[InlineAsmTemplatePiece::String("aesdeclast xmm0, xmm1".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm0)),
@@ -1207,7 +1209,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String(format!("sha1rnds4 xmm1, xmm2, {func}"))],
+                &[InlineAsmTemplatePiece::String(format!("sha1rnds4 xmm1, xmm2, {func}").into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1233,7 +1235,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("sha1msg1 xmm1, xmm2".to_string())],
+                &[InlineAsmTemplatePiece::String("sha1msg1 xmm1, xmm2".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1259,7 +1261,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("sha1msg2 xmm1, xmm2".to_string())],
+                &[InlineAsmTemplatePiece::String("sha1msg2 xmm1, xmm2".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1285,7 +1287,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("sha1nexte xmm1, xmm2".to_string())],
+                &[InlineAsmTemplatePiece::String("sha1nexte xmm1, xmm2".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1312,7 +1314,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("sha256rnds2 xmm1, xmm2".to_string())],
+                &[InlineAsmTemplatePiece::String("sha256rnds2 xmm1, xmm2".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1343,7 +1345,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("sha256msg1 xmm1, xmm2".to_string())],
+                &[InlineAsmTemplatePiece::String("sha256msg1 xmm1, xmm2".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1369,7 +1371,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
 
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("sha256msg2 xmm1, xmm2".to_string())],
+                &[InlineAsmTemplatePiece::String("sha256msg2 xmm1, xmm2".into())],
                 &[
                     CInlineAsmOperand::InOut {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::xmm1)),
@@ -1435,7 +1437,7 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>(
             let edx_place = res_place.place_field(fx, FieldIdx::new(1));
             codegen_inline_asm_inner(
                 fx,
-                &[InlineAsmTemplatePiece::String("rdtsc".to_string())],
+                &[InlineAsmTemplatePiece::String("rdtsc".into())],
                 &[
                     CInlineAsmOperand::Out {
                         reg: InlineAsmRegOrRegClass::Reg(InlineAsmReg::X86(X86InlineAsmReg::ax)),

compiler/rustc_feature/src/unstable.rs

@@ -205,6 +205,8 @@ declare_features! (
     (unstable, lifetime_capture_rules_2024, "1.76.0", None),
     /// Allows `#[link(..., cfg(..))]`; perma-unstable per #37406
     (unstable, link_cfg, "1.14.0", None),
+    /// Allows using `?Trait` trait bounds in more contexts.
+    (internal, more_maybe_bounds, "CURRENT_RUSTC_VERSION", None),
     /// Allows the `multiple_supertrait_upcastable` lint.
     (unstable, multiple_supertrait_upcastable, "1.69.0", None),
     /// Allow negative trait bounds. This is an internal-only feature for testing the trait solver!

compiler/rustc_hir/src/hir.rs

@@ -2832,7 +2832,11 @@ pub enum TyKind<'hir> {
     OpaqueDef(ItemId, &'hir [GenericArg<'hir>], bool),
     /// A trait object type `Bound1 + Bound2 + Bound3`
     /// where `Bound` is a trait or a lifetime.
-    TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
+    TraitObject(
+        &'hir [(PolyTraitRef<'hir>, TraitBoundModifier)],
+        &'hir Lifetime,
+        TraitObjectSyntax,
+    ),
     /// Unused for now.
     Typeof(&'hir AnonConst),
     /// `TyKind::Infer` means the type should be inferred instead of it having been

compiler/rustc_hir/src/intravisit.rs

@@ -902,7 +902,9 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) -> V::Resul
             try_visit!(visitor.visit_array_length(length));
         }
         TyKind::TraitObject(bounds, ref lifetime, _syntax) => {
-            walk_list!(visitor, visit_poly_trait_ref, bounds);
+            for (bound, _modifier) in bounds {
+                try_visit!(visitor.visit_poly_trait_ref(bound));
+            }
             try_visit!(visitor.visit_lifetime(lifetime));
         }
         TyKind::Typeof(ref expression) => try_visit!(visitor.visit_anon_const(expression)),

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -831,7 +831,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GATArgsCollector<'tcx> {
 
 fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool {
     match ty.kind {
-        hir::TyKind::TraitObject([trait_ref], ..) => match trait_ref.trait_ref.path.segments {
+        hir::TyKind::TraitObject([(trait_ref, _)], ..) => match trait_ref.trait_ref.path.segments {
             [s] => s.res.opt_def_id() == Some(trait_def_id.to_def_id()),
             _ => false,
         },