Use 'mir lifetime name more.

Some types have a `body: &'mir Body<'tcx>` and some have `body: &'a
Body<'tcx>`. The former is more readable, so this commit converts some
fo the latter to the former.

compiler/rustc_borrowck/src/dataflow.rs

@@ -120,24 +120,24 @@ 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, 'tcx> {
+pub struct Borrows<'mir, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    body: &'a Body<'tcx>,
+    body: &'mir Body<'tcx>,
 
-    borrow_set: &'a BorrowSet<'tcx>,
+    borrow_set: &'mir BorrowSet<'tcx>,
     borrows_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
-struct OutOfScopePrecomputer<'a, 'tcx> {
+struct OutOfScopePrecomputer<'mir, 'tcx> {
     visited: BitSet<mir::BasicBlock>,
     visit_stack: Vec<mir::BasicBlock>,
-    body: &'a Body<'tcx>,
-    regioncx: &'a RegionInferenceContext<'tcx>,
+    body: &'mir Body<'tcx>,
+    regioncx: &'mir RegionInferenceContext<'tcx>,
     borrows_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
-impl<'a, 'tcx> OutOfScopePrecomputer<'a, 'tcx> {
-    fn new(body: &'a Body<'tcx>, regioncx: &'a RegionInferenceContext<'tcx>) -> Self {
+impl<'mir, 'tcx> OutOfScopePrecomputer<'mir, 'tcx> {
+    fn new(body: &'mir Body<'tcx>, regioncx: &'mir RegionInferenceContext<'tcx>) -> Self {
         OutOfScopePrecomputer {
             visited: BitSet::new_empty(body.basic_blocks.len()),
             visit_stack: vec![],
@@ -240,17 +240,17 @@ pub fn calculate_borrows_out_of_scope_at_location<'tcx>(
     prec.borrows_out_of_scope_at_location
 }
 
-struct PoloniusOutOfScopePrecomputer<'a, 'tcx> {
+struct PoloniusOutOfScopePrecomputer<'mir, 'tcx> {
     visited: BitSet<mir::BasicBlock>,
     visit_stack: Vec<mir::BasicBlock>,
-    body: &'a Body<'tcx>,
-    regioncx: &'a RegionInferenceContext<'tcx>,
+    body: &'mir Body<'tcx>,
+    regioncx: &'mir RegionInferenceContext<'tcx>,
 
     loans_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
-impl<'a, 'tcx> PoloniusOutOfScopePrecomputer<'a, 'tcx> {
-    fn new(body: &'a Body<'tcx>, regioncx: &'a RegionInferenceContext<'tcx>) -> Self {
+impl<'mir, 'tcx> PoloniusOutOfScopePrecomputer<'mir, 'tcx> {
+    fn new(body: &'mir Body<'tcx>, regioncx: &'mir RegionInferenceContext<'tcx>) -> Self {
         Self {
             visited: BitSet::new_empty(body.basic_blocks.len()),
             visit_stack: vec![],
@@ -403,12 +403,12 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> Borrows<'a, 'tcx> {
+impl<'mir, 'tcx> Borrows<'mir, 'tcx> {
     pub fn new(
         tcx: TyCtxt<'tcx>,
-        body: &'a Body<'tcx>,
-        regioncx: &'a RegionInferenceContext<'tcx>,
-        borrow_set: &'a BorrowSet<'tcx>,
+        body: &'mir Body<'tcx>,
+        regioncx: &'mir RegionInferenceContext<'tcx>,
+        borrow_set: &'mir BorrowSet<'tcx>,
     ) -> Self {
         let mut borrows_out_of_scope_at_location =
             calculate_borrows_out_of_scope_at_location(body, regioncx, borrow_set);

compiler/rustc_mir_dataflow/src/framework/direction.rs

@@ -287,12 +287,12 @@ impl Direction for Backward {
     }
 }
 
-struct BackwardSwitchIntEdgeEffectsApplier<'a, 'tcx, D, F> {
-    body: &'a mir::Body<'tcx>,
+struct BackwardSwitchIntEdgeEffectsApplier<'mir, 'tcx, D, F> {
+    body: &'mir mir::Body<'tcx>,
     pred: BasicBlock,
-    exit_state: &'a mut D,
+    exit_state: &'mir mut D,
     bb: BasicBlock,
-    propagate: &'a mut F,
+    propagate: &'mir mut F,
     effects_applied: bool,
 }
 
@@ -523,9 +523,9 @@ impl Direction for Forward {
     }
 }
 
-struct ForwardSwitchIntEdgeEffectsApplier<'a, D, F> {
-    exit_state: &'a mut D,
-    targets: &'a SwitchTargets,
+struct ForwardSwitchIntEdgeEffectsApplier<'mir, D, F> {
+    exit_state: &'mir mut D,
+    targets: &'mir SwitchTargets,
     propagate: F,
 
     effects_applied: bool,

compiler/rustc_mir_dataflow/src/framework/engine.rs

@@ -128,12 +128,12 @@ where
 }
 
 /// A solver for dataflow problems.
-pub struct Engine<'a, 'tcx, A>
+pub struct Engine<'mir, 'tcx, A>
 where
     A: Analysis<'tcx>,
 {
     tcx: TyCtxt<'tcx>,
-    body: &'a mir::Body<'tcx>,
+    body: &'mir mir::Body<'tcx>,
     entry_sets: IndexVec<BasicBlock, A::Domain>,
     pass_name: Option<&'static str>,
     analysis: A,
@@ -147,14 +147,14 @@ where
     apply_statement_trans_for_block: Option<Box<dyn Fn(BasicBlock, &mut A::Domain)>>,
 }
 
-impl<'a, 'tcx, A, D, T> Engine<'a, 'tcx, A>
+impl<'mir, 'tcx, A, D, T> Engine<'mir, 'tcx, A>
 where
     A: GenKillAnalysis<'tcx, Idx = T, Domain = D>,
     D: Clone + JoinSemiLattice + GenKill<T> + BitSetExt<T>,
     T: Idx,
 {
     /// Creates a new `Engine` to solve a gen-kill dataflow problem.
-    pub fn new_gen_kill(tcx: TyCtxt<'tcx>, body: &'a mir::Body<'tcx>, mut analysis: A) -> Self {
+    pub fn new_gen_kill(tcx: TyCtxt<'tcx>, body: &'mir mir::Body<'tcx>, mut analysis: A) -> Self {
         // If there are no back-edges in the control-flow graph, we only ever need to apply the
         // transfer function for each block exactly once (assuming that we process blocks in RPO).
         //
@@ -186,7 +186,7 @@ where
     }
 }
 
-impl<'a, 'tcx, A, D> Engine<'a, 'tcx, A>
+impl<'mir, 'tcx, A, D> Engine<'mir, 'tcx, A>
 where
     A: Analysis<'tcx, Domain = D>,
     D: Clone + JoinSemiLattice,
@@ -196,13 +196,13 @@ where
     ///
     /// Gen-kill problems should use `new_gen_kill`, which will coalesce transfer functions for
     /// better performance.
-    pub fn new_generic(tcx: TyCtxt<'tcx>, body: &'a mir::Body<'tcx>, analysis: A) -> Self {
+    pub fn new_generic(tcx: TyCtxt<'tcx>, body: &'mir mir::Body<'tcx>, analysis: A) -> Self {
         Self::new(tcx, body, analysis, None)
     }
 
     fn new(
         tcx: TyCtxt<'tcx>,
-        body: &'a mir::Body<'tcx>,
+        body: &'mir mir::Body<'tcx>,
         analysis: A,
         apply_statement_trans_for_block: Option<Box<dyn Fn(BasicBlock, &mut A::Domain)>>,
     ) -> Self {