Rollup merge of #130022 - nnethercote:dataflow-borrowck-lifetimes, r=oli-obk

Dataflow/borrowck lifetime cleanups

These commits remove a bunch of unnecessary lifetimes from structs involved in dataflow/borrowck.

r? ``@lqd``

3 files changed, 47 insertions, 59 deletions

diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index a9c56174206..90243cd2910 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -872,9 +872,9 @@ fn compute_storage_conflicts<'mir, 'tcx>(
     storage_conflicts
 }
 
-struct StorageConflictVisitor<'mir, 'tcx, 's> {
-    body: &'mir Body<'tcx>,
-    saved_locals: &'s CoroutineSavedLocals,
+struct StorageConflictVisitor<'a, 'tcx> {
+    body: &'a Body<'tcx>,
+    saved_locals: &'a CoroutineSavedLocals,
     // FIXME(tmandry): Consider using sparse bitsets here once we have good
     // benchmarks for coroutines.
     local_conflicts: BitMatrix<Local, Local>,
@@ -882,8 +882,8 @@ struct StorageConflictVisitor<'mir, 'tcx, 's> {
     eligible_storage_live: BitSet<Local>,
 }
 
-impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
-    for StorageConflictVisitor<'mir, 'tcx, '_>
+impl<'a, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'a, 'tcx, R>
+    for StorageConflictVisitor<'a, 'tcx>
 {
     type FlowState = BitSet<Local>;
 
@@ -891,7 +891,7 @@ impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
         &mut self,
         _results: &mut R,
         state: &Self::FlowState,
-        _statement: &'mir Statement<'tcx>,
+        _statement: &'a Statement<'tcx>,
         loc: Location,
     ) {
         self.apply_state(state, loc);
@@ -901,14 +901,14 @@ impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
         &mut self,
         _results: &mut R,
         state: &Self::FlowState,
-        _terminator: &'mir Terminator<'tcx>,
+        _terminator: &'a Terminator<'tcx>,
         loc: Location,
     ) {
         self.apply_state(state, loc);
     }
 }
 
-impl StorageConflictVisitor<'_, '_, '_> {
+impl StorageConflictVisitor<'_, '_> {
     fn apply_state(&mut self, flow_state: &BitSet<Local>, loc: Location) {
         // Ignore unreachable blocks.
         if let TerminatorKind::Unreachable = self.body.basic_blocks[loc.block].terminator().kind {
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index d365989c8df..79f12be4bc3 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -838,14 +838,14 @@ impl<'tcx> MutVisitor<'tcx> for Patch<'tcx> {
     }
 }
 
-struct OperandCollector<'tcx, 'map, 'locals, 'a> {
+struct OperandCollector<'a, 'locals, 'tcx> {
     state: &'a State<FlatSet<Scalar>>,
     visitor: &'a mut Collector<'tcx, 'locals>,
-    ecx: &'map mut InterpCx<'tcx, DummyMachine>,
-    map: &'map Map<'tcx>,
+    ecx: &'a mut InterpCx<'tcx, DummyMachine>,
+    map: &'a Map<'tcx>,
 }
 
-impl<'tcx> Visitor<'tcx> for OperandCollector<'tcx, '_, '_, '_> {
+impl<'tcx> Visitor<'tcx> for OperandCollector<'_, '_, 'tcx> {
     fn visit_projection_elem(
         &mut self,
         _: PlaceRef<'tcx>,
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index fba4320fb5d..cb729792dc5 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -98,9 +98,9 @@ impl<'tcx> crate::MirPass<'tcx> for ElaborateDrops {
 /// Records unwind edges which are known to be unreachable, because they are in `drop` terminators
 /// that can't drop anything.
 #[instrument(level = "trace", skip(body, flow_inits), ret)]
-fn compute_dead_unwinds<'mir, 'tcx>(
-    body: &'mir Body<'tcx>,
-    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'_, 'mir, 'tcx>>,
+fn compute_dead_unwinds<'a, 'tcx>(
+    body: &'a Body<'tcx>,
+    flow_inits: &mut ResultsCursor<'a, 'tcx, MaybeInitializedPlaces<'a, 'tcx>>,
 ) -> BitSet<BasicBlock> {
     // We only need to do this pass once, because unwind edges can only
     // reach cleanup blocks, which can't have unwind edges themselves.
@@ -121,12 +121,12 @@ fn compute_dead_unwinds<'mir, 'tcx>(
     dead_unwinds
 }
 
-struct InitializationData<'a, 'mir, 'tcx> {
-    inits: ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'a, 'mir, 'tcx>>,
-    uninits: ResultsCursor<'mir, 'tcx, MaybeUninitializedPlaces<'a, 'mir, 'tcx>>,
+struct InitializationData<'a, 'tcx> {
+    inits: ResultsCursor<'a, 'tcx, MaybeInitializedPlaces<'a, 'tcx>>,
+    uninits: ResultsCursor<'a, 'tcx, MaybeUninitializedPlaces<'a, 'tcx>>,
 }
 
-impl InitializationData<'_, '_, '_> {
+impl InitializationData<'_, '_> {
     fn seek_before(&mut self, loc: Location) {
         self.inits.seek_before_primary_effect(loc);
         self.uninits.seek_before_primary_effect(loc);
@@ -137,45 +137,35 @@ impl InitializationData<'_, '_, '_> {
     }
 }
 
-struct Elaborator<'a, 'b, 'mir, 'tcx> {
-    ctxt: &'a mut ElaborateDropsCtxt<'b, 'mir, 'tcx>,
-}
-
-impl fmt::Debug for Elaborator<'_, '_, '_, '_> {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Ok(())
-    }
-}
-
-impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, '_, 'tcx> {
+impl<'a, 'tcx> DropElaborator<'a, 'tcx> for ElaborateDropsCtxt<'a, 'tcx> {
     type Path = MovePathIndex;
 
     fn patch(&mut self) -> &mut MirPatch<'tcx> {
-        &mut self.ctxt.patch
+        &mut self.patch
     }
 
     fn body(&self) -> &'a Body<'tcx> {
-        self.ctxt.body
+        self.body
     }
 
     fn tcx(&self) -> TyCtxt<'tcx> {
-        self.ctxt.tcx
+        self.tcx
     }
 
     fn param_env(&self) -> ty::ParamEnv<'tcx> {
-        self.ctxt.param_env()
+        self.param_env()
     }
 
     #[instrument(level = "debug", skip(self), ret)]
     fn drop_style(&self, path: Self::Path, mode: DropFlagMode) -> DropStyle {
         let ((maybe_live, maybe_dead), multipart) = match mode {
-            DropFlagMode::Shallow => (self.ctxt.init_data.maybe_live_dead(path), false),
+            DropFlagMode::Shallow => (self.init_data.maybe_live_dead(path), false),
             DropFlagMode::Deep => {
                 let mut some_live = false;
                 let mut some_dead = false;
                 let mut children_count = 0;
-                on_all_children_bits(self.ctxt.move_data(), path, |child| {
-                    let (live, dead) = self.ctxt.init_data.maybe_live_dead(child);
+                on_all_children_bits(self.move_data(), path, |child| {
+                    let (live, dead) = self.init_data.maybe_live_dead(child);
                     debug!("elaborate_drop: state({:?}) = {:?}", child, (live, dead));
                     some_live |= live;
                     some_dead |= dead;
@@ -195,25 +185,25 @@ impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, '_, 'tcx> {
     fn clear_drop_flag(&mut self, loc: Location, path: Self::Path, mode: DropFlagMode) {
         match mode {
             DropFlagMode::Shallow => {
-                self.ctxt.set_drop_flag(loc, path, DropFlagState::Absent);
+                self.set_drop_flag(loc, path, DropFlagState::Absent);
             }
             DropFlagMode::Deep => {
-                on_all_children_bits(self.ctxt.move_data(), path, |child| {
-                    self.ctxt.set_drop_flag(loc, child, DropFlagState::Absent)
+                on_all_children_bits(self.move_data(), path, |child| {
+                    self.set_drop_flag(loc, child, DropFlagState::Absent)
                 });
             }
         }
     }
 
     fn field_subpath(&self, path: Self::Path, field: FieldIdx) -> Option<Self::Path> {
-        rustc_mir_dataflow::move_path_children_matching(self.ctxt.move_data(), path, |e| match e {
+        rustc_mir_dataflow::move_path_children_matching(self.move_data(), path, |e| match e {
             ProjectionElem::Field(idx, _) => idx == field,
             _ => false,
         })
     }
 
     fn array_subpath(&self, path: Self::Path, index: u64, size: u64) -> Option<Self::Path> {
-        rustc_mir_dataflow::move_path_children_matching(self.ctxt.move_data(), path, |e| match e {
+        rustc_mir_dataflow::move_path_children_matching(self.move_data(), path, |e| match e {
             ProjectionElem::ConstantIndex { offset, min_length, from_end } => {
                 debug_assert!(size == min_length, "min_length should be exact for arrays");
                 assert!(!from_end, "from_end should not be used for array element ConstantIndex");
@@ -224,34 +214,40 @@ impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, '_, 'tcx> {
     }
 
     fn deref_subpath(&self, path: Self::Path) -> Option<Self::Path> {
-        rustc_mir_dataflow::move_path_children_matching(self.ctxt.move_data(), path, |e| {
+        rustc_mir_dataflow::move_path_children_matching(self.move_data(), path, |e| {
             e == ProjectionElem::Deref
         })
     }
 
     fn downcast_subpath(&self, path: Self::Path, variant: VariantIdx) -> Option<Self::Path> {
-        rustc_mir_dataflow::move_path_children_matching(self.ctxt.move_data(), path, |e| match e {
+        rustc_mir_dataflow::move_path_children_matching(self.move_data(), path, |e| match e {
             ProjectionElem::Downcast(_, idx) => idx == variant,
             _ => false,
         })
     }
 
     fn get_drop_flag(&mut self, path: Self::Path) -> Option<Operand<'tcx>> {
-        self.ctxt.drop_flag(path).map(Operand::Copy)
+        self.drop_flag(path).map(Operand::Copy)
     }
 }
 
-struct ElaborateDropsCtxt<'a, 'mir, 'tcx> {
+struct ElaborateDropsCtxt<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    body: &'mir Body<'tcx>,
+    body: &'a Body<'tcx>,
     env: &'a MoveDataParamEnv<'tcx>,
-    init_data: InitializationData<'a, 'mir, 'tcx>,
+    init_data: InitializationData<'a, 'tcx>,
     drop_flags: IndexVec<MovePathIndex, Option<Local>>,
     patch: MirPatch<'tcx>,
 }
 
-impl<'b, 'mir, 'tcx> ElaborateDropsCtxt<'b, 'mir, 'tcx> {
-    fn move_data(&self) -> &'b MoveData<'tcx> {
+impl fmt::Debug for ElaborateDropsCtxt<'_, '_> {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        Ok(())
+    }
+}
+
+impl<'a, 'tcx> ElaborateDropsCtxt<'a, 'tcx> {
+    fn move_data(&self) -> &'a MoveData<'tcx> {
         &self.env.move_data
     }
 
@@ -370,15 +366,7 @@ impl<'b, 'mir, 'tcx> ElaborateDropsCtxt<'b, 'mir, 'tcx> {
                         }
                     };
                     self.init_data.seek_before(self.body.terminator_loc(bb));
-                    elaborate_drop(
-                        &mut Elaborator { ctxt: self },
-                        terminator.source_info,
-                        place,
-                        path,
-                        target,
-                        unwind,
-                        bb,
-                    )
+                    elaborate_drop(self, terminator.source_info, place, path, target, unwind, bb)
                 }
                 LookupResult::Parent(None) => {}
                 LookupResult::Parent(Some(_)) => {