Auto merge of rust-lang#144637 - Zalathar:rollup-t1yo1jy, r=Zalathar

Rollup of 6 pull requests

Successful merges:

 - rust-lang#144560 (coverage: Treat `#[automatically_derived]` as `#[coverage(off)]`)
 - rust-lang#144566 (Simplify `align_of_val::<[T]>(…)` → `align_of::<T>()`)
 - rust-lang#144587 (expand: Micro-optimize prelude injection)
 - rust-lang#144589 (Account for `.yield` in illegal postfix operator message)
 - rust-lang#144615 (Make resolve_fn_signature responsible for its own rib.)
 - rust-lang#144634 (Fix typo in `DropGuard` doc)

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

Author: bors

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -110,18 +110,10 @@ pub enum DeprecatedSince {
     Err,
 }
 
-#[derive(
-    Copy,
-    Debug,
-    Eq,
-    PartialEq,
-    Encodable,
-    Decodable,
-    Clone,
-    HashStable_Generic,
-    PrintAttribute
-)]
-pub enum CoverageStatus {
+/// Successfully-parsed value of a `#[coverage(..)]` attribute.
+#[derive(Copy, Debug, Eq, PartialEq, Encodable, Decodable, Clone)]
+#[derive(HashStable_Generic, PrintAttribute)]
+pub enum CoverageAttrKind {
     On,
     Off,
 }
@@ -304,8 +296,8 @@ pub enum AttributeKind {
     /// Represents `#[const_trait]`.
     ConstTrait(Span),
 
-    /// Represents `#[coverage]`.
-    Coverage(Span, CoverageStatus),
+    /// Represents `#[coverage(..)]`.
+    Coverage(Span, CoverageAttrKind),
 
     ///Represents `#[rustc_deny_explicit_impl]`.
     DenyExplicitImpl(Span),

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -1,4 +1,4 @@
-use rustc_attr_data_structures::{AttributeKind, CoverageStatus, OptimizeAttr, UsedBy};
+use rustc_attr_data_structures::{AttributeKind, CoverageAttrKind, OptimizeAttr, UsedBy};
 use rustc_feature::{AttributeTemplate, template};
 use rustc_session::parse::feature_err;
 use rustc_span::{Span, Symbol, sym};
@@ -78,16 +78,16 @@ impl<S: Stage> SingleAttributeParser<S> for CoverageParser {
             return None;
         };
 
-        let status = match arg.path().word_sym() {
-            Some(sym::off) => CoverageStatus::Off,
-            Some(sym::on) => CoverageStatus::On,
+        let kind = match arg.path().word_sym() {
+            Some(sym::off) => CoverageAttrKind::Off,
+            Some(sym::on) => CoverageAttrKind::On,
             None | Some(_) => {
                 fail_incorrect_argument(arg.span());
                 return None;
             }
         };
 
-        Some(AttributeKind::Coverage(cx.attr_span, status))
+        Some(AttributeKind::Coverage(cx.attr_span, kind))
     }
 }
 

compiler/rustc_builtin_macros/src/standard_library_imports.rs

@@ -47,8 +47,6 @@ pub fn inject(
         ast::ItemKind::ExternCrate(None, Ident::new(name, ident_span)),
     );
 
-    krate.items.insert(0, item);
-
     let root = (edition == Edition2015).then_some(kw::PathRoot);
 
     let import_path = root
@@ -75,6 +73,6 @@ pub fn inject(
         }),
     );
 
-    krate.items.insert(0, use_item);
+    krate.items.splice(0..0, [item, use_item]);
     krate.items.len() - orig_num_items
 }

compiler/rustc_mir_transform/src/coverage/query.rs

@@ -1,4 +1,4 @@
-use rustc_attr_data_structures::{AttributeKind, CoverageStatus, find_attr};
+use rustc_attr_data_structures::{AttributeKind, CoverageAttrKind, find_attr};
 use rustc_index::bit_set::DenseBitSet;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::coverage::{BasicCoverageBlock, CoverageIdsInfo, CoverageKind, MappingKind};
@@ -32,16 +32,6 @@ fn is_eligible_for_coverage(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
         return false;
     }
 
-    // Don't instrument functions with `#[automatically_derived]` on their
-    // enclosing impl block, on the assumption that most users won't care about
-    // coverage for derived impls.
-    if let Some(impl_of) = tcx.impl_of_assoc(def_id.to_def_id())
-        && tcx.is_automatically_derived(impl_of)
-    {
-        trace!("InstrumentCoverage skipped for {def_id:?} (automatically derived)");
-        return false;
-    }
-
     if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::NAKED) {
         trace!("InstrumentCoverage skipped for {def_id:?} (`#[naked]`)");
         return false;
@@ -57,20 +47,32 @@ fn is_eligible_for_coverage(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
 
 /// Query implementation for `coverage_attr_on`.
 fn coverage_attr_on(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
-    // Check for annotations directly on this def.
-    if let Some(coverage_status) =
-        find_attr!(tcx.get_all_attrs(def_id), AttributeKind::Coverage(_, status) => status)
+    // Check for a `#[coverage(..)]` attribute on this def.
+    if let Some(kind) =
+        find_attr!(tcx.get_all_attrs(def_id), AttributeKind::Coverage(_sp, kind) => kind)
     {
-        *coverage_status == CoverageStatus::On
-    } else {
-        match tcx.opt_local_parent(def_id) {
-            // Check the parent def (and so on recursively) until we find an
-            // enclosing attribute or reach the crate root.
-            Some(parent) => tcx.coverage_attr_on(parent),
-            // We reached the crate root without seeing a coverage attribute, so
-            // allow coverage instrumentation by default.
-            None => true,
+        match kind {
+            CoverageAttrKind::On => return true,
+            CoverageAttrKind::Off => return false,
         }
+    };
+
+    // Treat `#[automatically_derived]` as an implied `#[coverage(off)]`, on
+    // the assumption that most users won't want coverage for derived impls.
+    //
+    // This affects not just the associated items of an impl block, but also
+    // any closures and other nested functions within those associated items.
+    if tcx.is_automatically_derived(def_id.to_def_id()) {
+        return false;
+    }
+
+    // Check the parent def (and so on recursively) until we find an
+    // enclosing attribute or reach the crate root.
+    match tcx.opt_local_parent(def_id) {
+        Some(parent) => tcx.coverage_attr_on(parent),
+        // We reached the crate root without seeing a coverage attribute, so
+        // allow coverage instrumentation by default.
+        None => true,
     }
 }
 

compiler/rustc_mir_transform/src/instsimplify.rs

@@ -55,6 +55,7 @@ impl<'tcx> crate::MirPass<'tcx> for InstSimplify {
 
             let terminator = block.terminator.as_mut().unwrap();
             ctx.simplify_primitive_clone(terminator, &mut block.statements);
+            ctx.simplify_align_of_slice_val(terminator, &mut block.statements);
             ctx.simplify_intrinsic_assert(terminator);
             ctx.simplify_nounwind_call(terminator);
             simplify_duplicate_switch_targets(terminator);
@@ -252,6 +253,36 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
         terminator.kind = TerminatorKind::Goto { target: *destination_block };
     }
 
+    // Convert `align_of_val::<[T]>(ptr)` to `align_of::<T>()`, since the
+    // alignment of a slice doesn't actually depend on metadata at all
+    // and the element type is always `Sized`.
+    //
+    // This is here so it can run after inlining, where it's more useful.
+    // (LowerIntrinsics is done in cleanup, before the optimization passes.)
+    fn simplify_align_of_slice_val(
+        &self,
+        terminator: &mut Terminator<'tcx>,
+        statements: &mut Vec<Statement<'tcx>>,
+    ) {
+        if let TerminatorKind::Call {
+            func, args, destination, target: Some(destination_block), ..
+        } = &terminator.kind
+            && args.len() == 1
+            && let Some((fn_def_id, generics)) = func.const_fn_def()
+            && self.tcx.is_intrinsic(fn_def_id, sym::align_of_val)
+            && let ty::Slice(elem_ty) = *generics.type_at(0).kind()
+        {
+            statements.push(Statement::new(
+                terminator.source_info,
+                StatementKind::Assign(Box::new((
+                    *destination,
+                    Rvalue::NullaryOp(NullOp::AlignOf, elem_ty),
+                ))),
+            ));
+            terminator.kind = TerminatorKind::Goto { target: *destination_block };
+        }
+    }
+
     fn simplify_nounwind_call(&self, terminator: &mut Terminator<'tcx>) {
         let TerminatorKind::Call { ref func, ref mut unwind, .. } = terminator.kind else {
             return;

compiler/rustc_parse/src/parser/expr.rs

@@ -785,9 +785,13 @@ impl<'a> Parser<'a> {
                     ExprKind::Call(_, _) => "a function call",
                     ExprKind::Await(_, _) => "`.await`",
                     ExprKind::Use(_, _) => "`.use`",
+                    ExprKind::Yield(YieldKind::Postfix(_)) => "`.yield`",
                     ExprKind::Match(_, _, MatchKind::Postfix) => "a postfix match",
                     ExprKind::Err(_) => return Ok(with_postfix),
-                    _ => unreachable!("parse_dot_or_call_expr_with_ shouldn't produce this"),
+                    _ => unreachable!(
+                        "did not expect {:?} as an illegal postfix operator following cast",
+                        with_postfix.kind
+                    ),
                 }
             );
             let mut err = self.dcx().struct_span_err(span, msg);

compiler/rustc_resolve/src/late.rs

@@ -910,22 +910,15 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                     span,
                     |this| {
                         this.visit_generic_params(&fn_ptr.generic_params, false);
-                        this.with_lifetime_rib(
-                            LifetimeRibKind::AnonymousCreateParameter {
-                                binder: ty.id,
-                                report_in_path: false,
-                            },
-                            |this| {
-                                this.resolve_fn_signature(
-                                    ty.id,
-                                    false,
-                                    // We don't need to deal with patterns in parameters, because
-                                    // they are not possible for foreign or bodiless functions.
-                                    fn_ptr.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
-                                    &fn_ptr.decl.output,
-                                )
-                            },
-                        );
+                        this.resolve_fn_signature(
+                            ty.id,
+                            false,
+                            // We don't need to deal with patterns in parameters, because
+                            // they are not possible for foreign or bodiless functions.
+                            fn_ptr.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
+                            &fn_ptr.decl.output,
+                            false,
+                        )
                     },
                 )
             }
@@ -1042,19 +1035,12 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                 self.visit_fn_header(&sig.header);
                 self.visit_ident(ident);
                 self.visit_generics(generics);
-                self.with_lifetime_rib(
-                    LifetimeRibKind::AnonymousCreateParameter {
-                        binder: fn_id,
-                        report_in_path: false,
-                    },
-                    |this| {
-                        this.resolve_fn_signature(
-                            fn_id,
-                            sig.decl.has_self(),
-                            sig.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
-                            &sig.decl.output,
-                        );
-                    },
+                self.resolve_fn_signature(
+                    fn_id,
+                    sig.decl.has_self(),
+                    sig.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
+                    &sig.decl.output,
+                    false,
                 );
                 return;
             }
@@ -1080,22 +1066,15 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                             .coroutine_kind
                             .map(|coroutine_kind| coroutine_kind.return_id());
 
-                        this.with_lifetime_rib(
-                            LifetimeRibKind::AnonymousCreateParameter {
-                                binder: fn_id,
-                                report_in_path: coro_node_id.is_some(),
-                            },
-                            |this| {
-                                this.resolve_fn_signature(
-                                    fn_id,
-                                    declaration.has_self(),
-                                    declaration
-                                        .inputs
-                                        .iter()
-                                        .map(|Param { pat, ty, .. }| (Some(&**pat), &**ty)),
-                                    &declaration.output,
-                                );
-                            },
+                        this.resolve_fn_signature(
+                            fn_id,
+                            declaration.has_self(),
+                            declaration
+                                .inputs
+                                .iter()
+                                .map(|Param { pat, ty, .. }| (Some(&**pat), &**ty)),
+                            &declaration.output,
+                            coro_node_id.is_some(),
                         );
 
                         if let Some(contract) = contract {
@@ -1307,19 +1286,12 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                             kind: LifetimeBinderKind::PolyTrait,
                             ..
                         } => {
-                            self.with_lifetime_rib(
-                                LifetimeRibKind::AnonymousCreateParameter {
-                                    binder,
-                                    report_in_path: false,
-                                },
-                                |this| {
-                                    this.resolve_fn_signature(
-                                        binder,
-                                        false,
-                                        p_args.inputs.iter().map(|ty| (None, &**ty)),
-                                        &p_args.output,
-                                    )
-                                },
+                            self.resolve_fn_signature(
+                                binder,
+                                false,
+                                p_args.inputs.iter().map(|ty| (None, &**ty)),
+                                &p_args.output,
+                                false,
                             );
                             break;
                         }
@@ -2236,25 +2208,32 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         has_self: bool,
         inputs: impl Iterator<Item = (Option<&'ast Pat>, &'ast Ty)> + Clone,
         output_ty: &'ast FnRetTy,
+        report_elided_lifetimes_in_path: bool,
     ) {
-        // Add each argument to the rib.
-        let elision_lifetime = self.resolve_fn_params(has_self, inputs);
-        debug!(?elision_lifetime);
-
-        let outer_failures = take(&mut self.diag_metadata.current_elision_failures);
-        let output_rib = if let Ok(res) = elision_lifetime.as_ref() {
-            self.r.lifetime_elision_allowed.insert(fn_id);
-            LifetimeRibKind::Elided(*res)
-        } else {
-            LifetimeRibKind::ElisionFailure
+        let rib = LifetimeRibKind::AnonymousCreateParameter {
+            binder: fn_id,
+            report_in_path: report_elided_lifetimes_in_path,
         };
-        self.with_lifetime_rib(output_rib, |this| visit::walk_fn_ret_ty(this, output_ty));
-        let elision_failures =
-            replace(&mut self.diag_metadata.current_elision_failures, outer_failures);
-        if !elision_failures.is_empty() {
-            let Err(failure_info) = elision_lifetime else { bug!() };
-            self.report_missing_lifetime_specifiers(elision_failures, Some(failure_info));
-        }
+        self.with_lifetime_rib(rib, |this| {
+            // Add each argument to the rib.
+            let elision_lifetime = this.resolve_fn_params(has_self, inputs);
+            debug!(?elision_lifetime);
+
+            let outer_failures = take(&mut this.diag_metadata.current_elision_failures);
+            let output_rib = if let Ok(res) = elision_lifetime.as_ref() {
+                this.r.lifetime_elision_allowed.insert(fn_id);
+                LifetimeRibKind::Elided(*res)
+            } else {
+                LifetimeRibKind::ElisionFailure
+            };
+            this.with_lifetime_rib(output_rib, |this| visit::walk_fn_ret_ty(this, output_ty));
+            let elision_failures =
+                replace(&mut this.diag_metadata.current_elision_failures, outer_failures);
+            if !elision_failures.is_empty() {
+                let Err(failure_info) = elision_lifetime else { bug!() };
+                this.report_missing_lifetime_specifiers(elision_failures, Some(failure_info));
+            }
+        });
     }
 
     /// Resolve inside function parameters and parameter types.

library/core/src/mem/drop_guard.rs

@@ -4,7 +4,7 @@ use crate::ops::{Deref, DerefMut};
 
 /// Wrap a value and run a closure when dropped.
 ///
-/// This is useful for quickly creating desructors inline.
+/// This is useful for quickly creating destructors inline.
 ///
 /// # Examples
 ///