Rollup merge of #69714 - spastorino:place-ref-lifetime, r=oli-obk

Make PlaceRef take just one lifetime

r? @eddyb

src/librustc/mir/mod.rs

@@ -1827,9 +1827,9 @@ rustc_index::newtype_index! {
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct PlaceRef<'a, 'tcx> {
+pub struct PlaceRef<'tcx> {
     pub local: Local,
-    pub projection: &'a [PlaceElem<'tcx>],
+    pub projection: &'tcx [PlaceElem<'tcx>],
 }
 
 impl<'tcx> Place<'tcx> {
@@ -1864,7 +1864,7 @@ impl<'tcx> Place<'tcx> {
         self.as_ref().as_local()
     }
 
-    pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
+    pub fn as_ref(&self) -> PlaceRef<'tcx> {
         PlaceRef { local: self.local, projection: &self.projection }
     }
 }
@@ -1875,7 +1875,7 @@ impl From<Local> for Place<'_> {
     }
 }
 
-impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
+impl<'tcx> PlaceRef<'tcx> {
     /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
     /// a single deref of a local.
     //

src/librustc_codegen_ssa/mir/analyze.rs

@@ -97,7 +97,7 @@ impl<Bx: BuilderMethods<'a, 'tcx>> LocalAnalyzer<'mir, 'a, 'tcx, Bx> {
 
     fn process_place(
         &mut self,
-        place_ref: &mir::PlaceRef<'_, 'tcx>,
+        place_ref: &mir::PlaceRef<'tcx>,
         context: PlaceContext,
         location: Location,
     ) {

src/librustc_codegen_ssa/mir/operand.rs

@@ -364,7 +364,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     fn maybe_codegen_consume_direct(
         &mut self,
         bx: &mut Bx,
-        place_ref: mir::PlaceRef<'_, 'tcx>,
+        place_ref: mir::PlaceRef<'tcx>,
     ) -> Option<OperandRef<'tcx, Bx::Value>> {
         debug!("maybe_codegen_consume_direct(place_ref={:?})", place_ref);
 
@@ -408,7 +408,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn codegen_consume(
         &mut self,
         bx: &mut Bx,
-        place_ref: mir::PlaceRef<'_, 'tcx>,
+        place_ref: mir::PlaceRef<'tcx>,
     ) -> OperandRef<'tcx, Bx::Value> {
         debug!("codegen_consume(place_ref={:?})", place_ref);
 

src/librustc_codegen_ssa/mir/place.rs

@@ -408,7 +408,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn codegen_place(
         &mut self,
         bx: &mut Bx,
-        place_ref: mir::PlaceRef<'_, 'tcx>,
+        place_ref: mir::PlaceRef<'tcx>,
     ) -> PlaceRef<'tcx, Bx::Value> {
         debug!("codegen_place(place_ref={:?})", place_ref);
         let cx = self.cx;
@@ -497,7 +497,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         result
     }
 
-    pub fn monomorphized_place_ty(&self, place_ref: mir::PlaceRef<'_, 'tcx>) -> Ty<'tcx> {
+    pub fn monomorphized_place_ty(&self, place_ref: mir::PlaceRef<'tcx>) -> Ty<'tcx> {
         let tcx = self.cx.tcx();
         let place_ty = mir::Place::ty_from(place_ref.local, place_ref.projection, *self.mir, tcx);
         self.monomorphize(&place_ty.ty)

src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs

@@ -51,7 +51,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &mut self,
         location: Location,
         desired_action: InitializationRequiringAction,
-        (moved_place, used_place, span): (PlaceRef<'cx, 'tcx>, PlaceRef<'cx, 'tcx>, Span),
+        (moved_place, used_place, span): (PlaceRef<'tcx>, PlaceRef<'tcx>, Span),
         mpi: MovePathIndex,
     ) {
         debug!(
@@ -647,7 +647,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 // borrowed place and look for a access to a different field of the same union.
                 let Place { local, projection } = second_borrowed_place;
 
-                let mut cursor = projection.as_ref();
+                let mut cursor = &projection[..];
                 while let [proj_base @ .., elem] = cursor {
                     cursor = proj_base;
 
@@ -1521,7 +1521,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         err.buffer(&mut self.errors_buffer);
     }
 
-    fn classify_drop_access_kind(&self, place: PlaceRef<'cx, 'tcx>) -> StorageDeadOrDrop<'tcx> {
+    fn classify_drop_access_kind(&self, place: PlaceRef<'tcx>) -> StorageDeadOrDrop<'tcx> {
         let tcx = self.infcx.tcx;
         match place.projection {
             [] => StorageDeadOrDrop::LocalStorageDead,

src/librustc_mir/borrow_check/diagnostics/mod.rs

@@ -51,7 +51,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     pub(super) fn add_moved_or_invoked_closure_note(
         &self,
         location: Location,
-        place: PlaceRef<'cx, 'tcx>,
+        place: PlaceRef<'tcx>,
         diag: &mut DiagnosticBuilder<'_>,
     ) {
         debug!("add_moved_or_invoked_closure_note: location={:?} place={:?}", location, place);
@@ -139,7 +139,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     /// End-user visible description of `place` if one can be found. If the
     /// place is a temporary for instance, None will be returned.
-    pub(super) fn describe_place(&self, place_ref: PlaceRef<'cx, 'tcx>) -> Option<String> {
+    pub(super) fn describe_place(&self, place_ref: PlaceRef<'tcx>) -> Option<String> {
         self.describe_place_with_options(place_ref, IncludingDowncast(false))
     }
 
@@ -149,7 +149,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// `Downcast` and `IncludingDowncast` is true
     pub(super) fn describe_place_with_options(
         &self,
-        place: PlaceRef<'cx, 'tcx>,
+        place: PlaceRef<'tcx>,
         including_downcast: IncludingDowncast,
     ) -> Option<String> {
         let mut buf = String::new();
@@ -162,7 +162,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// Appends end-user visible description of `place` to `buf`.
     fn append_place_to_string(
         &self,
-        place: PlaceRef<'cx, 'tcx>,
+        place: PlaceRef<'tcx>,
         buf: &mut String,
         mut autoderef: bool,
         including_downcast: &IncludingDowncast,
@@ -303,7 +303,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     }
 
     /// End-user visible description of the `field`nth field of `base`
-    fn describe_field(&self, place: PlaceRef<'cx, 'tcx>, field: Field) -> String {
+    fn describe_field(&self, place: PlaceRef<'tcx>, field: Field) -> String {
         // FIXME Place2 Make this work iteratively
         match place {
             PlaceRef { local, projection: [] } => {
@@ -399,7 +399,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     pub(super) fn borrowed_content_source(
         &self,
-        deref_base: PlaceRef<'cx, 'tcx>,
+        deref_base: PlaceRef<'tcx>,
     ) -> BorrowedContentSource<'tcx> {
         let tcx = self.infcx.tcx;
 
@@ -694,7 +694,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// Finds the spans associated to a move or copy of move_place at location.
     pub(super) fn move_spans(
         &self,
-        moved_place: PlaceRef<'cx, 'tcx>, // Could also be an upvar.
+        moved_place: PlaceRef<'tcx>, // Could also be an upvar.
         location: Location,
     ) -> UseSpans {
         use self::UseSpans::*;
@@ -782,7 +782,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn closure_span(
         &self,
         def_id: DefId,
-        target_place: PlaceRef<'cx, 'tcx>,
+        target_place: PlaceRef<'tcx>,
         places: &Vec<Operand<'tcx>>,
     ) -> Option<(Span, Option<GeneratorKind>, Span)> {
         debug!(

src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs

@@ -23,7 +23,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         &mut self,
         access_place: &Place<'tcx>,
         span: Span,
-        the_place_err: PlaceRef<'cx, 'tcx>,
+        the_place_err: PlaceRef<'tcx>,
         error_access: AccessKind,
         location: Location,
     ) {

src/librustc_mir/borrow_check/mod.rs

@@ -86,6 +86,8 @@ crate struct Upvar {
     mutability: Mutability,
 }
 
+const DEREF_PROJECTION: &[PlaceElem<'_>; 1] = &[ProjectionElem::Deref];
+
 pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers { mir_borrowck, ..*providers };
 }
@@ -466,10 +468,10 @@ crate struct MirBorrowckCtxt<'cx, 'tcx> {
     /// `BTreeMap` is used to preserve the order of insertions when iterating. This is necessary
     /// when errors in the map are being re-added to the error buffer so that errors with the
     /// same primary span come out in a consistent order.
-    move_error_reported: BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'cx, 'tcx>, DiagnosticBuilder<'cx>)>,
+    move_error_reported: BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, DiagnosticBuilder<'cx>)>,
     /// This field keeps track of errors reported in the checking of uninitialized variables,
     /// so that we don't report seemingly duplicate errors.
-    uninitialized_error_reported: FxHashSet<PlaceRef<'cx, 'tcx>>,
+    uninitialized_error_reported: FxHashSet<PlaceRef<'tcx>>,
     /// Errors to be reported buffer
     errors_buffer: Vec<Diagnostic>,
     /// This field keeps track of all the local variables that are declared mut and are mutated.
@@ -841,9 +843,9 @@ enum InitializationRequiringAction {
     PartialAssignment,
 }
 
-struct RootPlace<'d, 'tcx> {
+struct RootPlace<'tcx> {
     place_local: Local,
-    place_projection: &'d [PlaceElem<'tcx>],
+    place_projection: &'tcx [PlaceElem<'tcx>],
     is_local_mutation_allowed: LocalMutationIsAllowed,
 }
 
@@ -1413,7 +1415,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     ) {
         debug!("check_for_invalidation_at_exit({:?})", borrow);
         let place = &borrow.borrowed_place;
-        let deref = [ProjectionElem::Deref];
         let mut root_place = PlaceRef { local: place.local, projection: &[] };
 
         // FIXME(nll-rfc#40): do more precise destructor tracking here. For now
@@ -1427,7 +1428,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 // Thread-locals might be dropped after the function exits
                 // We have to dereference the outer reference because
                 // borrows don't conflict behind shared references.
-                root_place.projection = &deref;
+                root_place.projection = DEREF_PROJECTION;
                 (true, true)
             } else {
                 (false, self.locals_are_invalidated_at_exit)
@@ -1526,7 +1527,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &mut self,
         location: Location,
         desired_action: InitializationRequiringAction,
-        place_span: (PlaceRef<'cx, 'tcx>, Span),
+        place_span: (PlaceRef<'tcx>, Span),
         flow_state: &Flows<'cx, 'tcx>,
     ) {
         let maybe_uninits = &flow_state.uninits;
@@ -1592,7 +1593,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &mut self,
         location: Location,
         desired_action: InitializationRequiringAction,
-        place_span: (PlaceRef<'cx, 'tcx>, Span),
+        place_span: (PlaceRef<'tcx>, Span),
         maybe_uninits: &BitSet<MovePathIndex>,
         from: u32,
         to: u32,
@@ -1631,7 +1632,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &mut self,
         location: Location,
         desired_action: InitializationRequiringAction,
-        place_span: (PlaceRef<'cx, 'tcx>, Span),
+        place_span: (PlaceRef<'tcx>, Span),
         flow_state: &Flows<'cx, 'tcx>,
     ) {
         let maybe_uninits = &flow_state.uninits;
@@ -1709,10 +1710,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// An Err result includes a tag indicated why the search failed.
     /// Currently this can only occur if the place is built off of a
     /// static variable, as we do not track those in the MoveData.
-    fn move_path_closest_to(
-        &mut self,
-        place: PlaceRef<'_, 'tcx>,
-    ) -> (PlaceRef<'cx, 'tcx>, MovePathIndex) {
+    fn move_path_closest_to(&mut self, place: PlaceRef<'tcx>) -> (PlaceRef<'tcx>, MovePathIndex) {
         match self.move_data.rev_lookup.find(place) {
             LookupResult::Parent(Some(mpi)) | LookupResult::Exact(mpi) => {
                 (self.move_data.move_paths[mpi].place.as_ref(), mpi)
@@ -1721,7 +1719,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         }
     }
 
-    fn move_path_for_place(&mut self, place: PlaceRef<'_, 'tcx>) -> Option<MovePathIndex> {
+    fn move_path_for_place(&mut self, place: PlaceRef<'tcx>) -> Option<MovePathIndex> {
         // If returns None, then there is no move path corresponding
         // to a direct owner of `place` (which means there is nothing
         // that borrowck tracks for its analysis).
@@ -1816,7 +1814,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         fn check_parent_of_field<'cx, 'tcx>(
             this: &mut MirBorrowckCtxt<'cx, 'tcx>,
             location: Location,
-            base: PlaceRef<'cx, 'tcx>,
+            base: PlaceRef<'tcx>,
             span: Span,
             flow_state: &Flows<'cx, 'tcx>,
         ) {
@@ -2029,7 +2027,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     }
 
     /// Adds the place into the used mutable variables set
-    fn add_used_mut<'d>(&mut self, root_place: RootPlace<'d, 'tcx>, flow_state: &Flows<'cx, 'tcx>) {
+    fn add_used_mut(&mut self, root_place: RootPlace<'tcx>, flow_state: &Flows<'cx, 'tcx>) {
         match root_place {
             RootPlace { place_local: local, place_projection: [], is_local_mutation_allowed } => {
                 // If the local may have been initialized, and it is now currently being
@@ -2063,11 +2061,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     /// Whether this value can be written or borrowed mutably.
     /// Returns the root place if the place passed in is a projection.
-    fn is_mutable<'d>(
+    fn is_mutable(
         &self,
-        place: PlaceRef<'d, 'tcx>,
+        place: PlaceRef<'tcx>,
         is_local_mutation_allowed: LocalMutationIsAllowed,
-    ) -> Result<RootPlace<'d, 'tcx>, PlaceRef<'d, 'tcx>> {
+    ) -> Result<RootPlace<'tcx>, PlaceRef<'tcx>> {
         match place {
             PlaceRef { local, projection: [] } => {
                 let local = &self.body.local_decls[local];
@@ -2218,7 +2216,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// then returns the index of the field being projected. Note that this closure will always
     /// be `self` in the current MIR, because that is the only time we directly access the fields
     /// of a closure type.
-    pub fn is_upvar_field_projection(&self, place_ref: PlaceRef<'cx, 'tcx>) -> Option<Field> {
+    pub fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<Field> {
         let mut place_projection = place_ref.projection;
         let mut by_ref = false;
 

src/librustc_mir/borrow_check/places_conflict.rs

@@ -48,7 +48,7 @@ pub(super) fn borrow_conflicts_with_place<'tcx>(
     body: &Body<'tcx>,
     borrow_place: &Place<'tcx>,
     borrow_kind: BorrowKind,
-    access_place: PlaceRef<'_, 'tcx>,
+    access_place: PlaceRef<'tcx>,
     access: AccessDepth,
     bias: PlaceConflictBias,
 ) -> bool {
@@ -73,7 +73,7 @@ fn place_components_conflict<'tcx>(
     body: &Body<'tcx>,
     borrow_place: &Place<'tcx>,
     borrow_kind: BorrowKind,
-    access_place: PlaceRef<'_, 'tcx>,
+    access_place: PlaceRef<'tcx>,
     access: AccessDepth,
     bias: PlaceConflictBias,
 ) -> bool {

src/librustc_mir/borrow_check/prefixes.rs

@@ -13,12 +13,12 @@ use rustc::mir::{Place, PlaceRef, ProjectionElem, ReadOnlyBodyAndCache};
 use rustc::ty::{self, TyCtxt};
 use rustc_hir as hir;
 
-pub trait IsPrefixOf<'cx, 'tcx> {
-    fn is_prefix_of(&self, other: PlaceRef<'cx, 'tcx>) -> bool;
+pub trait IsPrefixOf<'tcx> {
+    fn is_prefix_of(&self, other: PlaceRef<'tcx>) -> bool;
 }
 
-impl<'cx, 'tcx> IsPrefixOf<'cx, 'tcx> for PlaceRef<'cx, 'tcx> {
-    fn is_prefix_of(&self, other: PlaceRef<'cx, 'tcx>) -> bool {
+impl<'tcx> IsPrefixOf<'tcx> for PlaceRef<'tcx> {
+    fn is_prefix_of(&self, other: PlaceRef<'tcx>) -> bool {
         self.local == other.local
             && self.projection.len() <= other.projection.len()
             && self.projection == &other.projection[..self.projection.len()]
@@ -29,7 +29,7 @@ pub(super) struct Prefixes<'cx, 'tcx> {
     body: ReadOnlyBodyAndCache<'cx, 'tcx>,
     tcx: TyCtxt<'tcx>,
     kind: PrefixSet,
-    next: Option<PlaceRef<'cx, 'tcx>>,
+    next: Option<PlaceRef<'tcx>>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
@@ -50,15 +50,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// terminating the iteration early based on `kind`.
     pub(super) fn prefixes(
         &self,
-        place_ref: PlaceRef<'cx, 'tcx>,
+        place_ref: PlaceRef<'tcx>,
         kind: PrefixSet,
     ) -> Prefixes<'cx, 'tcx> {
         Prefixes { next: Some(place_ref), kind, body: self.body, tcx: self.infcx.tcx }
     }
 }
 
 impl<'cx, 'tcx> Iterator for Prefixes<'cx, 'tcx> {
-    type Item = PlaceRef<'cx, 'tcx>;
+    type Item = PlaceRef<'tcx>;
     fn next(&mut self) -> Option<Self::Item> {
         let mut cursor = self.next?;
 

src/librustc_mir/dataflow/move_paths/builder.rs

@@ -483,7 +483,7 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
         self.builder.data.loc_map[self.loc].push(move_out);
     }
 
-    fn gather_init(&mut self, place: PlaceRef<'cx, 'tcx>, kind: InitKind) {
+    fn gather_init(&mut self, place: PlaceRef<'tcx>, kind: InitKind) {
         debug!("gather_init({:?}, {:?})", self.loc, place);
 
         let mut place = place;