Auto merge of #89089 - JohnTitor:rollup-6s6mccx, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - #87960 (Suggest replacing an inexisting field for an unmentioned field)
 - #88855 (Allow simd_shuffle to accept vectors of any length)
 - #88966 (Check for shadowing issues involving block labels)
 - #88996 (Fix linting when trailing macro expands to a trailing semi)
 - #89017 (fix potential race in AtomicU64 time monotonizer)
 - #89021 (Add a separate error for `dyn Trait` in `const fn`)
 - #89051 (Add intra-doc links and small changes to `std::os` to be more consistent)
 - #89053 (refactor: VecDeques IntoIter fields to private)
 - #89055 (Suggest better place to add call parentheses for method expressions wrapped in parentheses)
 - #89081 (Fix a typo)

Failed merges:

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

Author: bors

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -918,12 +918,29 @@ fn generic_simd_intrinsic(
     }
 
     if let Some(stripped) = name_str.strip_prefix("simd_shuffle") {
-        let n: u64 = stripped.parse().unwrap_or_else(|_| {
-            span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
-        });
+        // If this intrinsic is the older "simd_shuffleN" form, simply parse the integer.
+        // If there is no suffix, use the index array length.
+        let n: u64 = if stripped.is_empty() {
+            // Make sure this is actually an array, since typeck only checks the length-suffixed
+            // version of this intrinsic.
+            match args[2].layout.ty.kind() {
+                ty::Array(ty, len) if matches!(ty.kind(), ty::Uint(ty::UintTy::U32)) => {
+                    len.try_eval_usize(bx.cx.tcx, ty::ParamEnv::reveal_all()).unwrap_or_else(|| {
+                        span_bug!(span, "could not evaluate shuffle index array length")
+                    })
+                }
+                _ => return_error!(
+                    "simd_shuffle index must be an array of `u32`, got `{}`",
+                    args[2].layout.ty
+                ),
+            }
+        } else {
+            stripped.parse().unwrap_or_else(|_| {
+                span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
+            })
+        };
 
         require_simd!(ret_ty, "return");
-
         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
         require!(
             out_len == n,

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -665,8 +665,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         if i == 2 && intrinsic.as_str().starts_with("simd_shuffle") {
                             if let mir::Operand::Constant(constant) = arg {
                                 let c = self.eval_mir_constant(constant);
-                                let (llval, ty) =
-                                    self.simd_shuffle_indices(&bx, constant.span, constant.ty(), c);
+                                let (llval, ty) = self.simd_shuffle_indices(
+                                    &bx,
+                                    constant.span,
+                                    self.monomorphize(constant.ty()),
+                                    c,
+                                );
                                 return OperandRef {
                                     val: Immediate(llval),
                                     layout: bx.layout_of(ty),

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -384,11 +384,11 @@ impl Checker<'mir, 'tcx> {
                         match pred.skip_binder() {
                             ty::ExistentialPredicate::AutoTrait(_)
                             | ty::ExistentialPredicate::Projection(_) => {
-                                self.check_op(ops::ty::TraitBound(kind))
+                                self.check_op(ops::ty::DynTrait(kind))
                             }
                             ty::ExistentialPredicate::Trait(trait_ref) => {
                                 if Some(trait_ref.def_id) != self.tcx.lang_items().sized_trait() {
-                                    self.check_op(ops::ty::TraitBound(kind))
+                                    self.check_op(ops::ty::DynTrait(kind))
                                 }
                             }
                         }

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -599,7 +599,7 @@ pub mod ty {
         }
 
         fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
-            let mut builder = feature_err(
+            let mut err = feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_fn_trait_bound,
                 span,
@@ -608,12 +608,51 @@ pub mod ty {
 
             match ccx.fn_sig() {
                 Some(fn_sig) if !fn_sig.span.contains(span) => {
-                    builder.span_label(fn_sig.span, "function declared as const here");
+                    err.span_label(fn_sig.span, "function declared as const here");
                 }
                 _ => {}
             }
 
-            builder
+            err
+        }
+    }
+
+    #[derive(Debug)]
+    pub struct DynTrait(pub mir::LocalKind);
+    impl NonConstOp for DynTrait {
+        fn importance(&self) -> DiagnosticImportance {
+            match self.0 {
+                mir::LocalKind::Var | mir::LocalKind::Temp => DiagnosticImportance::Secondary,
+                mir::LocalKind::ReturnPointer | mir::LocalKind::Arg => {
+                    DiagnosticImportance::Primary
+                }
+            }
+        }
+
+        fn status_in_item(&self, ccx: &ConstCx<'_, '_>) -> Status {
+            if ccx.const_kind() != hir::ConstContext::ConstFn {
+                Status::Allowed
+            } else {
+                Status::Unstable(sym::const_fn_trait_bound)
+            }
+        }
+
+        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+            let mut err = feature_err(
+                &ccx.tcx.sess.parse_sess,
+                sym::const_fn_trait_bound,
+                span,
+                "trait objects in const fn are unstable",
+            );
+
+            match ccx.fn_sig() {
+                Some(fn_sig) if !fn_sig.span.contains(span) => {
+                    err.span_label(fn_sig.span, "function declared as const here");
+                }
+                _ => {}
+            }
+
+            err
         }
     }
 

compiler/rustc_error_codes/src/error_codes/E0439.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 The length of the platform-intrinsic function `simd_shuffle` wasn't specified.
 
 Erroneous code example:
 
-```compile_fail,E0439
+```ignore (no longer emitted)
 #![feature(platform_intrinsics)]
 
 extern "platform-intrinsic" {

compiler/rustc_expand/src/expand.rs

@@ -1386,14 +1386,17 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
         // `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` lint if needed.
         // See #78991 for an investigation of treating macros in this position
         // as statements, rather than expressions, during parsing.
-        if let StmtKind::Expr(expr) = &stmt.kind {
-            if matches!(**expr, ast::Expr { kind: ast::ExprKind::MacCall(..), .. }) {
+        let res = match &stmt.kind {
+            StmtKind::Expr(expr)
+                if matches!(**expr, ast::Expr { kind: ast::ExprKind::MacCall(..), .. }) =>
+            {
                 self.cx.current_expansion.is_trailing_mac = true;
+                // Don't use `assign_id` for this statement - it may get removed
+                // entirely due to a `#[cfg]` on the contained expression
+                noop_flat_map_stmt(stmt, self)
             }
-        }
-
-        let res = assign_id!(self, &mut stmt.id, || noop_flat_map_stmt(stmt, self));
-
+            _ => assign_id!(self, &mut stmt.id, || noop_flat_map_stmt(stmt, self)),
+        };
         self.cx.current_expansion.is_trailing_mac = false;
         res
     }

compiler/rustc_resolve/src/late/lifetimes.rs

@@ -1652,7 +1652,11 @@ fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body<'_>) {
     }
 
     fn expression_label(ex: &hir::Expr<'_>) -> Option<Ident> {
-        if let hir::ExprKind::Loop(_, Some(label), ..) = ex.kind { Some(label.ident) } else { None }
+        match ex.kind {
+            hir::ExprKind::Loop(_, Some(label), ..) => Some(label.ident),
+            hir::ExprKind::Block(_, Some(label)) => Some(label.ident),
+            _ => None,
+        }
     }
 
     fn check_if_label_shadows_lifetime(tcx: TyCtxt<'_>, mut scope: ScopeRef<'_>, label: Ident) {

compiler/rustc_span/src/symbol.rs

@@ -1212,6 +1212,7 @@ symbols! {
         simd_select_bitmask,
         simd_shl,
         simd_shr,
+        simd_shuffle,
         simd_sub,
         simd_trunc,
         simd_xor,

compiler/rustc_typeck/src/check/expr.rs

@@ -1860,6 +1860,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 field,
                 expr_t,
                 expr,
+                None,
             );
         }
         err.emit();
@@ -1886,9 +1887,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             };
         let expr_snippet =
             self.tcx.sess.source_map().span_to_snippet(expr.span).unwrap_or(String::new());
-        if expr_is_call && expr_snippet.starts_with("(") && expr_snippet.ends_with(")") {
-            let after_open = expr.span.lo() + rustc_span::BytePos(1);
-            let before_close = expr.span.hi() - rustc_span::BytePos(1);
+        let is_wrapped = expr_snippet.starts_with("(") && expr_snippet.ends_with(")");
+        let after_open = expr.span.lo() + rustc_span::BytePos(1);
+        let before_close = expr.span.hi() - rustc_span::BytePos(1);
+
+        if expr_is_call && is_wrapped {
             err.multipart_suggestion(
                 "remove wrapping parentheses to call the method",
                 vec![
@@ -1898,12 +1901,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Applicability::MachineApplicable,
             );
         } else if !self.expr_in_place(expr.hir_id) {
+            // Suggest call parentheses inside the wrapping parentheses
+            let span = if is_wrapped {
+                expr.span.with_lo(after_open).with_hi(before_close)
+            } else {
+                expr.span
+            };
             self.suggest_method_call(
                 &mut err,
                 "use parentheses to call the method",
                 field,
                 expr_t,
                 expr,
+                Some(span),
             );
         } else {
             err.help("methods are immutable and cannot be assigned to");

compiler/rustc_typeck/src/check/intrinsic.rs

@@ -2,7 +2,7 @@
 //! intrinsics that the compiler exposes.
 
 use crate::errors::{
-    SimdShuffleMissingLength, UnrecognizedAtomicOperation, UnrecognizedIntrinsicFunction,
+    UnrecognizedAtomicOperation, UnrecognizedIntrinsicFunction,
     WrongNumberOfGenericArgumentsToIntrinsic,
 };
 use crate::require_same_types;
@@ -468,14 +468,17 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_reduce_max
         | sym::simd_reduce_min_nanless
         | sym::simd_reduce_max_nanless => (2, vec![param(0)], param(1)),
+        sym::simd_shuffle => (3, vec![param(0), param(0), param(1)], param(2)),
         name if name.as_str().starts_with("simd_shuffle") => {
             match name.as_str()["simd_shuffle".len()..].parse() {
                 Ok(n) => {
                     let params = vec![param(0), param(0), tcx.mk_array(tcx.types.u32, n)];
                     (2, params, param(1))
                 }
                 Err(_) => {
-                    tcx.sess.emit_err(SimdShuffleMissingLength { span: it.span, name });
+                    let msg =
+                        format!("unrecognized platform-specific intrinsic function: `{}`", name);
+                    tcx.sess.struct_span_err(it.span, &msg).emit();
                     return;
                 }
             }