Auto merge of rust-lang#3892 - rust-lang:rustup-2024-09-16, r=RalfJung

Automatic Rustup

Author: bors

compiler/rustc_abi/src/lib.rs

@@ -781,6 +781,14 @@ impl Align {
 }
 
 /// A pair of alignments, ABI-mandated and preferred.
+///
+/// The "preferred" alignment is an LLVM concept that is virtually meaningless to Rust code:
+/// it is not exposed semantically to programmers nor can they meaningfully affect it.
+/// The only concern for us is that preferred alignment must not be less than the mandated alignment
+/// and thus in practice the two values are almost always identical.
+///
+/// An example of a rare thing actually affected by preferred alignment is aligning of statics.
+/// It is of effectively no consequence for layout in structs and on the stack.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 #[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub struct AbiAndPrefAlign {

compiler/rustc_arena/src/lib.rs

@@ -614,34 +614,34 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
 
     pub trait ArenaAllocatable<'tcx, C = rustc_arena::IsNotCopy>: Sized {
         #[allow(clippy::mut_from_ref)]
-        fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self;
+        fn allocate_on(self, arena: &'tcx Arena<'tcx>) -> &'tcx mut Self;
         #[allow(clippy::mut_from_ref)]
-        fn allocate_from_iter<'a>(
-            arena: &'a Arena<'tcx>,
+        fn allocate_from_iter(
+            arena: &'tcx Arena<'tcx>,
             iter: impl ::std::iter::IntoIterator<Item = Self>,
-        ) -> &'a mut [Self];
+        ) -> &'tcx mut [Self];
     }
 
     // Any type that impls `Copy` can be arena-allocated in the `DroplessArena`.
     impl<'tcx, T: Copy> ArenaAllocatable<'tcx, rustc_arena::IsCopy> for T {
         #[inline]
         #[allow(clippy::mut_from_ref)]
-        fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self {
+        fn allocate_on(self, arena: &'tcx Arena<'tcx>) -> &'tcx mut Self {
             arena.dropless.alloc(self)
         }
         #[inline]
         #[allow(clippy::mut_from_ref)]
-        fn allocate_from_iter<'a>(
-            arena: &'a Arena<'tcx>,
+        fn allocate_from_iter(
+            arena: &'tcx Arena<'tcx>,
             iter: impl ::std::iter::IntoIterator<Item = Self>,
-        ) -> &'a mut [Self] {
+        ) -> &'tcx mut [Self] {
             arena.dropless.alloc_from_iter(iter)
         }
     }
     $(
         impl<'tcx> ArenaAllocatable<'tcx, rustc_arena::IsNotCopy> for $ty {
             #[inline]
-            fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self {
+            fn allocate_on(self, arena: &'tcx Arena<'tcx>) -> &'tcx mut Self {
                 if !::std::mem::needs_drop::<Self>() {
                     arena.dropless.alloc(self)
                 } else {
@@ -651,10 +651,10 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
 
             #[inline]
             #[allow(clippy::mut_from_ref)]
-            fn allocate_from_iter<'a>(
-                arena: &'a Arena<'tcx>,
+            fn allocate_from_iter(
+                arena: &'tcx Arena<'tcx>,
                 iter: impl ::std::iter::IntoIterator<Item = Self>,
-            ) -> &'a mut [Self] {
+            ) -> &'tcx mut [Self] {
                 if !::std::mem::needs_drop::<Self>() {
                     arena.dropless.alloc_from_iter(iter)
                 } else {
@@ -667,7 +667,7 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
     impl<'tcx> Arena<'tcx> {
         #[inline]
         #[allow(clippy::mut_from_ref)]
-        pub fn alloc<T: ArenaAllocatable<'tcx, C>, C>(&self, value: T) -> &mut T {
+        pub fn alloc<T: ArenaAllocatable<'tcx, C>, C>(&'tcx self, value: T) -> &mut T {
             value.allocate_on(self)
         }
 
@@ -691,7 +691,7 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
 
         #[allow(clippy::mut_from_ref)]
         pub fn alloc_from_iter<T: ArenaAllocatable<'tcx, C>, C>(
-            &self,
+            &'tcx self,
             iter: impl ::std::iter::IntoIterator<Item = T>,
         ) -> &mut [T] {
             T::allocate_from_iter(self, iter)

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -75,22 +75,9 @@ struct PostExpansionVisitor<'a> {
 
 impl<'a> PostExpansionVisitor<'a> {
     #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-    fn check_abi(&self, abi: ast::StrLit, constness: ast::Const) {
+    fn check_abi(&self, abi: ast::StrLit) {
         let ast::StrLit { symbol_unescaped, span, .. } = abi;
 
-        if let ast::Const::Yes(_) = constness {
-            match symbol_unescaped {
-                // Stable
-                sym::Rust | sym::C => {}
-                abi => gate!(
-                    &self,
-                    const_extern_fn,
-                    span,
-                    format!("`{}` as a `const fn` ABI is unstable", abi)
-                ),
-            }
-        }
-
         match abi::is_enabled(self.features, span, symbol_unescaped.as_str()) {
             Ok(()) => (),
             Err(abi::AbiDisabled::Unstable { feature, explain }) => {
@@ -110,9 +97,9 @@ impl<'a> PostExpansionVisitor<'a> {
         }
     }
 
-    fn check_extern(&self, ext: ast::Extern, constness: ast::Const) {
+    fn check_extern(&self, ext: ast::Extern) {
         if let ast::Extern::Explicit(abi, _) = ext {
-            self.check_abi(abi, constness);
+            self.check_abi(abi);
         }
     }
 
@@ -239,7 +226,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         match &i.kind {
             ast::ItemKind::ForeignMod(foreign_module) => {
                 if let Some(abi) = foreign_module.abi {
-                    self.check_abi(abi, ast::Const::No);
+                    self.check_abi(abi);
                 }
             }
 
@@ -341,7 +328,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         match &ty.kind {
             ast::TyKind::BareFn(bare_fn_ty) => {
                 // Function pointers cannot be `const`
-                self.check_extern(bare_fn_ty.ext, ast::Const::No);
+                self.check_extern(bare_fn_ty.ext);
                 self.check_late_bound_lifetime_defs(&bare_fn_ty.generic_params);
             }
             ast::TyKind::Never => {
@@ -446,7 +433,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
         if let Some(header) = fn_kind.header() {
             // Stability of const fn methods are covered in `visit_assoc_item` below.
-            self.check_extern(header.ext, header.constness);
+            self.check_extern(header.ext);
         }
 
         if let FnKind::Closure(ast::ClosureBinder::For { generic_params, .. }, ..) = fn_kind {

compiler/rustc_borrowck/src/constraints/graph.rs

@@ -97,11 +97,11 @@ impl<D: ConstraintGraphDirection> ConstraintGraph<D> {
     /// Given the constraint set from which this graph was built
     /// creates a region graph so that you can iterate over *regions*
     /// and not constraints.
-    pub(crate) fn region_graph<'rg, 'tcx>(
-        &'rg self,
-        set: &'rg OutlivesConstraintSet<'tcx>,
+    pub(crate) fn region_graph<'a, 'tcx>(
+        &'a self,
+        set: &'a OutlivesConstraintSet<'tcx>,
         static_region: RegionVid,
-    ) -> RegionGraph<'rg, 'tcx, D> {
+    ) -> RegionGraph<'a, 'tcx, D> {
         RegionGraph::new(set, self, static_region)
     }
 
@@ -130,15 +130,15 @@ impl<D: ConstraintGraphDirection> ConstraintGraph<D> {
     }
 }
 
-pub(crate) struct Edges<'s, 'tcx, D: ConstraintGraphDirection> {
-    graph: &'s ConstraintGraph<D>,
-    constraints: &'s OutlivesConstraintSet<'tcx>,
+pub(crate) struct Edges<'a, 'tcx, D: ConstraintGraphDirection> {
+    graph: &'a ConstraintGraph<D>,
+    constraints: &'a OutlivesConstraintSet<'tcx>,
     pointer: Option<OutlivesConstraintIndex>,
     next_static_idx: Option<usize>,
     static_region: RegionVid,
 }
 
-impl<'s, 'tcx, D: ConstraintGraphDirection> Iterator for Edges<'s, 'tcx, D> {
+impl<'a, 'tcx, D: ConstraintGraphDirection> Iterator for Edges<'a, 'tcx, D> {
     type Item = OutlivesConstraint<'tcx>;
 
     fn next(&mut self) -> Option<Self::Item> {
@@ -171,55 +171,55 @@ impl<'s, 'tcx, D: ConstraintGraphDirection> Iterator for Edges<'s, 'tcx, D> {
 /// This struct brings together a constraint set and a (normal, not
 /// reverse) constraint graph. It implements the graph traits and is
 /// usd for doing the SCC computation.
-pub(crate) struct RegionGraph<'s, 'tcx, D: ConstraintGraphDirection> {
-    set: &'s OutlivesConstraintSet<'tcx>,
-    constraint_graph: &'s ConstraintGraph<D>,
+pub(crate) struct RegionGraph<'a, 'tcx, D: ConstraintGraphDirection> {
+    set: &'a OutlivesConstraintSet<'tcx>,
+    constraint_graph: &'a ConstraintGraph<D>,
     static_region: RegionVid,
 }
 
-impl<'s, 'tcx, D: ConstraintGraphDirection> RegionGraph<'s, 'tcx, D> {
+impl<'a, 'tcx, D: ConstraintGraphDirection> RegionGraph<'a, 'tcx, D> {
     /// Creates a "dependency graph" where each region constraint `R1:
     /// R2` is treated as an edge `R1 -> R2`. We use this graph to
     /// construct SCCs for region inference but also for error
     /// reporting.
     pub(crate) fn new(
-        set: &'s OutlivesConstraintSet<'tcx>,
-        constraint_graph: &'s ConstraintGraph<D>,
+        set: &'a OutlivesConstraintSet<'tcx>,
+        constraint_graph: &'a ConstraintGraph<D>,
         static_region: RegionVid,
     ) -> Self {
         Self { set, constraint_graph, static_region }
     }
 
     /// Given a region `R`, iterate over all regions `R1` such that
     /// there exists a constraint `R: R1`.
-    pub(crate) fn outgoing_regions(&self, region_sup: RegionVid) -> Successors<'s, 'tcx, D> {
+    pub(crate) fn outgoing_regions(&self, region_sup: RegionVid) -> Successors<'a, 'tcx, D> {
         Successors {
             edges: self.constraint_graph.outgoing_edges(region_sup, self.set, self.static_region),
         }
     }
 }
 
-pub(crate) struct Successors<'s, 'tcx, D: ConstraintGraphDirection> {
-    edges: Edges<'s, 'tcx, D>,
+pub(crate) struct Successors<'a, 'tcx, D: ConstraintGraphDirection> {
+    edges: Edges<'a, 'tcx, D>,
 }
 
-impl<'s, 'tcx, D: ConstraintGraphDirection> Iterator for Successors<'s, 'tcx, D> {
+impl<'a, 'tcx, D: ConstraintGraphDirection> Iterator for Successors<'a, 'tcx, D> {
     type Item = RegionVid;
 
     fn next(&mut self) -> Option<Self::Item> {
         self.edges.next().map(|c| D::end_region(&c))
     }
 }
 
-impl<'s, 'tcx, D: ConstraintGraphDirection> graph::DirectedGraph for RegionGraph<'s, 'tcx, D> {
+impl<'a, 'tcx, D: ConstraintGraphDirection> graph::DirectedGraph for RegionGraph<'a, 'tcx, D> {
     type Node = RegionVid;
 
     fn num_nodes(&self) -> usize {
         self.constraint_graph.first_constraints.len()
     }
 }
 
-impl<'s, 'tcx, D: ConstraintGraphDirection> graph::Successors for RegionGraph<'s, 'tcx, D> {
+impl<'a, 'tcx, D: ConstraintGraphDirection> graph::Successors for RegionGraph<'a, 'tcx, D> {
     fn successors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node> {
         self.outgoing_regions(node)
     }

compiler/rustc_borrowck/src/dataflow.rs

@@ -112,16 +112,16 @@ pub struct Borrows<'a, 'tcx> {
     borrows_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
-struct OutOfScopePrecomputer<'mir, 'tcx> {
+struct OutOfScopePrecomputer<'a, 'tcx> {
     visited: BitSet<mir::BasicBlock>,
     visit_stack: Vec<mir::BasicBlock>,
-    body: &'mir Body<'tcx>,
-    regioncx: &'mir RegionInferenceContext<'tcx>,
+    body: &'a Body<'tcx>,
+    regioncx: &'a RegionInferenceContext<'tcx>,
     borrows_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
-impl<'mir, 'tcx> OutOfScopePrecomputer<'mir, 'tcx> {
-    fn new(body: &'mir Body<'tcx>, regioncx: &'mir RegionInferenceContext<'tcx>) -> Self {
+impl<'a, 'tcx> OutOfScopePrecomputer<'a, 'tcx> {
+    fn new(body: &'a Body<'tcx>, regioncx: &'a RegionInferenceContext<'tcx>) -> Self {
         OutOfScopePrecomputer {
             visited: BitSet::new_empty(body.basic_blocks.len()),
             visit_stack: vec![],
@@ -224,17 +224,17 @@ pub fn calculate_borrows_out_of_scope_at_location<'tcx>(
     prec.borrows_out_of_scope_at_location
 }
 
-struct PoloniusOutOfScopePrecomputer<'mir, 'tcx> {
+struct PoloniusOutOfScopePrecomputer<'a, 'tcx> {
     visited: BitSet<mir::BasicBlock>,
     visit_stack: Vec<mir::BasicBlock>,
-    body: &'mir Body<'tcx>,
-    regioncx: &'mir RegionInferenceContext<'tcx>,
+    body: &'a Body<'tcx>,
+    regioncx: &'a RegionInferenceContext<'tcx>,
 
     loans_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
-impl<'mir, 'tcx> PoloniusOutOfScopePrecomputer<'mir, 'tcx> {
-    fn new(body: &'mir Body<'tcx>, regioncx: &'mir RegionInferenceContext<'tcx>) -> Self {
+impl<'a, 'tcx> PoloniusOutOfScopePrecomputer<'a, 'tcx> {
+    fn new(body: &'a Body<'tcx>, regioncx: &'a RegionInferenceContext<'tcx>) -> Self {
         Self {
             visited: BitSet::new_empty(body.basic_blocks.len()),
             visit_stack: vec![],

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3553,7 +3553,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         location: Location,
         mpi: MovePathIndex,
     ) -> (Vec<MoveSite>, Vec<Location>) {
-        fn predecessor_locations<'tcx, 'a>(
+        fn predecessor_locations<'a, 'tcx>(
             body: &'a mir::Body<'tcx>,
             location: Location,
         ) -> impl Iterator<Item = Location> + Captures<'tcx> + 'a {

compiler/rustc_borrowck/src/diagnostics/find_use.rs

@@ -21,15 +21,15 @@ pub(crate) fn find<'tcx>(
     uf.find()
 }
 
-struct UseFinder<'cx, 'tcx> {
-    body: &'cx Body<'tcx>,
-    regioncx: &'cx Rc<RegionInferenceContext<'tcx>>,
+struct UseFinder<'a, 'tcx> {
+    body: &'a Body<'tcx>,
+    regioncx: &'a Rc<RegionInferenceContext<'tcx>>,
     tcx: TyCtxt<'tcx>,
     region_vid: RegionVid,
     start_point: Location,
 }
 
-impl<'cx, 'tcx> UseFinder<'cx, 'tcx> {
+impl<'a, 'tcx> UseFinder<'a, 'tcx> {
     fn find(&mut self) -> Option<Cause> {
         let mut queue = VecDeque::new();
         let mut visited = FxIndexSet::default();
@@ -93,8 +93,8 @@ impl<'cx, 'tcx> UseFinder<'cx, 'tcx> {
     }
 }
 
-struct DefUseVisitor<'cx, 'tcx> {
-    body: &'cx Body<'tcx>,
+struct DefUseVisitor<'a, 'tcx> {
+    body: &'a Body<'tcx>,
     tcx: TyCtxt<'tcx>,
     region_vid: RegionVid,
     def_use_result: Option<DefUseResult>,
@@ -106,7 +106,7 @@ enum DefUseResult {
     UseDrop { local: Local },
 }
 
-impl<'cx, 'tcx> Visitor<'tcx> for DefUseVisitor<'cx, 'tcx> {
+impl<'a, 'tcx> Visitor<'tcx> for DefUseVisitor<'a, 'tcx> {
     fn visit_local(&mut self, local: Local, context: PlaceContext, _: Location) {
         let local_ty = self.body.local_decls[local].ty;
 

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -558,7 +558,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 ty: Ty<'tcx>,
                 suggested: bool,
             }
-            impl<'a, 'cx, 'tcx> Visitor<'tcx> for SuggestIndexOperatorAlternativeVisitor<'a, 'cx, 'tcx> {
+            impl<'a, 'infcx, 'tcx> Visitor<'tcx> for SuggestIndexOperatorAlternativeVisitor<'a, 'infcx, 'tcx> {
                 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
                     hir::intravisit::walk_stmt(self, stmt);
                     let expr = match stmt.kind {

compiler/rustc_borrowck/src/polonius/loan_invalidations.rs

@@ -32,18 +32,18 @@ pub(super) fn emit_loan_invalidations<'tcx>(
     visitor.visit_body(body);
 }
 
-struct LoanInvalidationsGenerator<'cx, 'tcx> {
+struct LoanInvalidationsGenerator<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    all_facts: &'cx mut AllFacts,
-    location_table: &'cx LocationTable,
-    body: &'cx Body<'tcx>,
-    dominators: &'cx Dominators<BasicBlock>,
-    borrow_set: &'cx BorrowSet<'tcx>,
+    all_facts: &'a mut AllFacts,
+    location_table: &'a LocationTable,
+    body: &'a Body<'tcx>,
+    dominators: &'a Dominators<BasicBlock>,
+    borrow_set: &'a BorrowSet<'tcx>,
 }
 
 /// Visits the whole MIR and generates `invalidates()` facts.
 /// Most of the code implementing this was stolen from `borrow_check/mod.rs`.
-impl<'cx, 'tcx> Visitor<'tcx> for LoanInvalidationsGenerator<'cx, 'tcx> {
+impl<'a, 'tcx> Visitor<'tcx> for LoanInvalidationsGenerator<'a, 'tcx> {
     fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
         self.check_activations(location);
 
@@ -212,7 +212,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for LoanInvalidationsGenerator<'cx, 'tcx> {
     }
 }
 
-impl<'cx, 'tcx> LoanInvalidationsGenerator<'cx, 'tcx> {
+impl<'a, 'tcx> LoanInvalidationsGenerator<'a, 'tcx> {
     /// Simulates mutation of a place.
     fn mutate_place(&mut self, location: Location, place: Place<'tcx>, kind: AccessDepth) {
         self.access_place(