Remove unnecessary lifetimes in dataflow structs.

There are four related dataflow structs: `MaybeInitializedPlaces`,
`MaybeUninitializedPlaces`, and `EverInitializedPlaces`,
`DefinitelyInitializedPlaces`. They all have a `&Body` and a
`&MoveData<'tcx>` field. The first three use different lifetimes for the
two fields, but the last one uses the same lifetime for both.

This commit changes the first three to use the same lifetime, removing
the need for one of the lifetimes. Other structs that also lose a
lifetime as a result of this are `LivenessContext`, `LivenessResults`,
`InitializationData`.

It then does similar things in various other structs.

Author: nnethercote

compiler/rustc_borrowck/src/borrowck_errors.rs

@@ -8,7 +8,7 @@ use rustc_middle::span_bug;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
 
-impl<'infcx, 'tcx> crate::MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> crate::MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     pub(crate) fn dcx(&self) -> DiagCtxtHandle<'infcx> {
         self.infcx.dcx()
     }

compiler/rustc_borrowck/src/dataflow.rs

@@ -15,24 +15,24 @@ use tracing::debug;
 use crate::{places_conflict, BorrowSet, PlaceConflictBias, PlaceExt, RegionInferenceContext};
 
 /// The results of the dataflow analyses used by the borrow checker.
-pub(crate) struct BorrowckResults<'a, 'mir, 'tcx> {
-    pub(crate) borrows: Results<'tcx, Borrows<'a, 'mir, 'tcx>>,
-    pub(crate) uninits: Results<'tcx, MaybeUninitializedPlaces<'a, 'mir, 'tcx>>,
-    pub(crate) ever_inits: Results<'tcx, EverInitializedPlaces<'a, 'mir, 'tcx>>,
+pub(crate) struct BorrowckResults<'a, 'tcx> {
+    pub(crate) borrows: Results<'tcx, Borrows<'a, 'tcx>>,
+    pub(crate) uninits: Results<'tcx, MaybeUninitializedPlaces<'a, 'tcx>>,
+    pub(crate) ever_inits: Results<'tcx, EverInitializedPlaces<'a, 'tcx>>,
 }
 
 /// The transient state of the dataflow analyses used by the borrow checker.
 #[derive(Debug)]
-pub(crate) struct BorrowckFlowState<'a, 'mir, 'tcx> {
-    pub(crate) borrows: <Borrows<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
-    pub(crate) uninits: <MaybeUninitializedPlaces<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
-    pub(crate) ever_inits: <EverInitializedPlaces<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+pub(crate) struct BorrowckFlowState<'a, 'tcx> {
+    pub(crate) borrows: <Borrows<'a, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) uninits: <MaybeUninitializedPlaces<'a, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) ever_inits: <EverInitializedPlaces<'a, 'tcx> as AnalysisDomain<'tcx>>::Domain,
 }
 
-impl<'a, 'mir, 'tcx> ResultsVisitable<'tcx> for BorrowckResults<'a, 'mir, 'tcx> {
+impl<'a, 'tcx> ResultsVisitable<'tcx> for BorrowckResults<'a, 'tcx> {
     // All three analyses are forward, but we have to use just one here.
-    type Direction = <Borrows<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Direction;
-    type FlowState = BorrowckFlowState<'a, 'mir, 'tcx>;
+    type Direction = <Borrows<'a, 'tcx> as AnalysisDomain<'tcx>>::Direction;
+    type FlowState = BorrowckFlowState<'a, 'tcx>;
 
     fn new_flow_state(&self, body: &mir::Body<'tcx>) -> Self::FlowState {
         BorrowckFlowState {
@@ -106,10 +106,9 @@ rustc_index::newtype_index! {
 /// `BorrowIndex`, and maps each such index to a `BorrowData`
 /// describing the borrow. These indexes are used for representing the
 /// borrows in compact bitvectors.
-pub struct Borrows<'a, 'mir, 'tcx> {
+pub struct Borrows<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    body: &'mir Body<'tcx>,
-
+    body: &'a Body<'tcx>,
     borrow_set: &'a BorrowSet<'tcx>,
     borrows_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
@@ -389,10 +388,10 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
     }
 }
 
-impl<'a, 'mir, 'tcx> Borrows<'a, 'mir, 'tcx> {
+impl<'a, 'tcx> Borrows<'a, 'tcx> {
     pub fn new(
         tcx: TyCtxt<'tcx>,
-        body: &'mir Body<'tcx>,
+        body: &'a Body<'tcx>,
         regioncx: &RegionInferenceContext<'tcx>,
         borrow_set: &'a BorrowSet<'tcx>,
     ) -> Self {
@@ -494,7 +493,7 @@ impl<'a, 'mir, 'tcx> Borrows<'a, 'mir, 'tcx> {
     }
 }
 
-impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, '_, 'tcx> {
+impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, 'tcx> {
     type Domain = BitSet<BorrowIndex>;
 
     const NAME: &'static str = "borrows";
@@ -517,7 +516,7 @@ impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, '_, 'tcx> {
 ///   region stops containing the CFG points reachable from the issuing location.
 /// - we also kill loans of conflicting places when overwriting a shared path: e.g. borrows of
 ///   `a.b.c` when `a` is overwritten.
-impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, '_, 'tcx> {
+impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, 'tcx> {
     type Idx = BorrowIndex;
 
     fn domain_size(&self, _: &mir::Body<'tcx>) -> usize {
@@ -617,8 +616,8 @@ impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, '_, 'tcx> {
     }
 }
 
-impl DebugWithContext<Borrows<'_, '_, '_>> for BorrowIndex {
-    fn fmt_with(&self, ctxt: &Borrows<'_, '_, '_>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+impl DebugWithContext<Borrows<'_, '_>> for BorrowIndex {
+    fn fmt_with(&self, ctxt: &Borrows<'_, '_>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", ctxt.location(*self))
     }
 }

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -52,7 +52,7 @@ impl<'tcx> UniverseInfo<'tcx> {
 
     pub(crate) fn report_error(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'tcx>,
         placeholder: ty::PlaceholderRegion,
         error_element: RegionElement,
         cause: ObligationCause<'tcx>,
@@ -151,7 +151,7 @@ trait TypeOpInfo<'tcx> {
 
     fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
@@ -160,7 +160,7 @@ trait TypeOpInfo<'tcx> {
     #[instrument(level = "debug", skip(self, mbcx))]
     fn report_error(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'tcx>,
         placeholder: ty::PlaceholderRegion,
         error_element: RegionElement,
         cause: ObligationCause<'tcx>,
@@ -233,7 +233,7 @@ impl<'tcx> TypeOpInfo<'tcx> for PredicateQuery<'tcx> {
 
     fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
@@ -277,7 +277,7 @@ where
 
     fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
@@ -324,7 +324,7 @@ impl<'tcx> TypeOpInfo<'tcx> for AscribeUserTypeQuery<'tcx> {
 
     fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
@@ -357,7 +357,7 @@ impl<'tcx> TypeOpInfo<'tcx> for crate::type_check::InstantiateOpaqueType<'tcx> {
 
     fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, 'infcx, 'tcx>,
         _cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -69,7 +69,7 @@ enum StorageDeadOrDrop<'tcx> {
     Destructor(Ty<'tcx>),
 }
 
-impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     pub(crate) fn report_use_of_moved_or_uninitialized(
         &mut self,
         location: Location,
@@ -4358,11 +4358,7 @@ enum AnnotatedBorrowFnSignature<'tcx> {
 impl<'tcx> AnnotatedBorrowFnSignature<'tcx> {
     /// Annotate the provided diagnostic with information about borrow from the fn signature that
     /// helps explain.
-    pub(crate) fn emit(
-        &self,
-        cx: &MirBorrowckCtxt<'_, '_, '_, 'tcx>,
-        diag: &mut Diag<'_>,
-    ) -> String {
+    pub(crate) fn emit(&self, cx: &MirBorrowckCtxt<'_, '_, 'tcx>, diag: &mut Diag<'_>) -> String {
         match self {
             &AnnotatedBorrowFnSignature::Closure { argument_ty, argument_span } => {
                 diag.span_label(

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -390,7 +390,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
     }
 }
 
-impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
     fn free_region_constraint_info(
         &self,
         borrow_region: RegionVid,

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -68,7 +68,7 @@ pub(super) struct DescribePlaceOpt {
 
 pub(super) struct IncludingTupleField(pub(super) bool);
 
-impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     /// Adds a suggestion when a closure is invoked twice with a moved variable or when a closure
     /// is moved after being invoked.
     ///
@@ -772,7 +772,7 @@ struct CapturedMessageOpt {
     maybe_reinitialized_locations_is_empty: bool,
 }
 
-impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     /// Finds the spans associated to a move or copy of move_place at location.
     pub(super) fn move_spans(
         &self,

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -93,7 +93,7 @@ enum GroupedMoveError<'tcx> {
     },
 }
 
-impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     pub(crate) fn report_move_errors(&mut self) {
         let grouped_errors = self.group_move_errors();
         for error in grouped_errors {

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -32,7 +32,7 @@ pub(crate) enum AccessKind {
     Mutate,
 }
 
-impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     pub(crate) fn report_mutability_error(
         &mut self,
         access_place: Place<'tcx>,

compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs

@@ -76,7 +76,7 @@ impl OutlivesSuggestionBuilder {
     /// Returns a name for the region if it is suggestable. See `region_name_is_suggestable`.
     fn region_vid_to_name(
         &self,
-        mbcx: &MirBorrowckCtxt<'_, '_, '_, '_>,
+        mbcx: &MirBorrowckCtxt<'_, '_, '_>,
         region: RegionVid,
     ) -> Option<RegionName> {
         mbcx.give_region_a_name(region).filter(Self::region_name_is_suggestable)
@@ -85,7 +85,7 @@ impl OutlivesSuggestionBuilder {
     /// Compiles a list of all suggestions to be printed in the final big suggestion.
     fn compile_all_suggestions(
         &self,
-        mbcx: &MirBorrowckCtxt<'_, '_, '_, '_>,
+        mbcx: &MirBorrowckCtxt<'_, '_, '_>,
     ) -> SmallVec<[SuggestedConstraint; 2]> {
         let mut suggested = SmallVec::new();
 
@@ -161,7 +161,7 @@ impl OutlivesSuggestionBuilder {
     /// Emit an intermediate note on the given `Diag` if the involved regions are suggestable.
     pub(crate) fn intermediate_suggestion(
         &mut self,
-        mbcx: &MirBorrowckCtxt<'_, '_, '_, '_>,
+        mbcx: &MirBorrowckCtxt<'_, '_, '_>,
         errci: &ErrorConstraintInfo<'_>,
         diag: &mut Diag<'_>,
     ) {
@@ -180,7 +180,7 @@ impl OutlivesSuggestionBuilder {
 
     /// If there is a suggestion to emit, add a diagnostic to the buffer. This is the final
     /// suggestion including all collected constraints.
-    pub(crate) fn add_suggestion(&self, mbcx: &mut MirBorrowckCtxt<'_, '_, '_, '_>) {
+    pub(crate) fn add_suggestion(&self, mbcx: &mut MirBorrowckCtxt<'_, '_, '_>) {
         // No constraints to add? Done.
         if self.constraints_to_add.is_empty() {
             debug!("No constraints to suggest.");

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -156,7 +156,7 @@ pub(crate) struct ErrorConstraintInfo<'tcx> {
     pub(super) span: Span,
 }
 
-impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     /// Converts a region inference variable into a `ty::Region` that
     /// we can use for error reporting. If `r` is universally bound,
     /// then we use the name that we have on record for it. If `r` is