Remove in_band_lifetimes from rustc_mir_transform

This one is a heavy `'tcx` user.

Two interesting ones:

This one had the `'tcx` declared on the function, despite the trait taking a `'tcx`:
```diff
-impl Visitor<'_> for UsedLocals {
+impl<'tcx> Visitor<'tcx> for UsedLocals {
     fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
```

This one use in-band for one, and underscore for the other:
```diff
-pub fn remove_dead_blocks(tcx: TyCtxt<'tcx>, body: &mut Body<'_>) {
+pub fn remove_dead_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
```

compiler/rustc_mir_transform/src/add_retag.rs

@@ -34,7 +34,7 @@ fn is_stable(place: PlaceRef<'_>) -> bool {
 }
 
 /// Determine whether this type may be a reference (or box), and thus needs retagging.
-fn may_be_reference(ty: Ty<'tcx>) -> bool {
+fn may_be_reference(ty: Ty<'_>) -> bool {
     match ty.kind() {
         // Primitive types that are not references
         ty::Bool

compiler/rustc_mir_transform/src/check_const_item_mutation.rs

@@ -23,7 +23,7 @@ struct ConstMutationChecker<'a, 'tcx> {
     target_local: Option<Local>,
 }
 
-impl<'a, 'tcx> ConstMutationChecker<'a, 'tcx> {
+impl<'tcx> ConstMutationChecker<'_, 'tcx> {
     fn is_const_item(&self, local: Local) -> Option<DefId> {
         if let Some(box LocalInfo::ConstRef { def_id }) = self.body.local_decls[local].local_info {
             Some(def_id)
@@ -95,7 +95,7 @@ impl<'a, 'tcx> ConstMutationChecker<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for ConstMutationChecker<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> {
     fn visit_statement(&mut self, stmt: &Statement<'tcx>, loc: Location) {
         if let StatementKind::Assign(box (lhs, _)) = &stmt.kind {
             // Check for assignment to fields of a constant

compiler/rustc_mir_transform/src/check_packed_ref.rs

@@ -66,7 +66,7 @@ fn builtin_derive_def_id(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
     }
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for PackedRefChecker<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> {
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         // Make sure we know where in the MIR we are.
         self.source_info = terminator.source_info;

compiler/rustc_mir_transform/src/check_unsafety.rs

@@ -46,7 +46,7 @@ impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for UnsafetyChecker<'_, 'tcx> {
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         self.source_info = terminator.source_info;
         match terminator.kind {
@@ -244,7 +244,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
+impl<'tcx> UnsafetyChecker<'_, 'tcx> {
     fn require_unsafe(&mut self, kind: UnsafetyViolationKind, details: UnsafetyViolationDetails) {
         // Violations can turn out to be `UnsafeFn` during analysis, but they should not start out as such.
         assert_ne!(kind, UnsafetyViolationKind::UnsafeFn);
@@ -397,7 +397,7 @@ struct UnusedUnsafeVisitor<'a> {
     unsafe_blocks: &'a mut Vec<(hir::HirId, bool)>,
 }
 
-impl<'a, 'tcx> intravisit::Visitor<'tcx> for UnusedUnsafeVisitor<'a> {
+impl<'tcx> intravisit::Visitor<'tcx> for UnusedUnsafeVisitor<'_> {
     type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {

compiler/rustc_mir_transform/src/const_debuginfo.rs

@@ -89,7 +89,7 @@ fn find_optimization_oportunities<'tcx>(body: &Body<'tcx>) -> Vec<(Local, Consta
     eligable_locals
 }
 
-impl<'tcx> Visitor<'tcx> for LocalUseVisitor {
+impl Visitor<'_> for LocalUseVisitor {
     fn visit_local(&mut self, local: &Local, context: PlaceContext, location: Location) {
         if context.is_mutating_use() {
             self.local_mutating_uses[*local] = self.local_mutating_uses[*local].saturating_add(1);

compiler/rustc_mir_transform/src/const_goto.rs

@@ -54,7 +54,7 @@ impl<'tcx> MirPass<'tcx> for ConstGoto {
     }
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for ConstGotoOptimizationFinder<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for ConstGotoOptimizationFinder<'_, 'tcx> {
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         let _: Option<_> = try {
             let target = terminator.kind.as_goto()?;

compiler/rustc_mir_transform/src/const_prop.rs

@@ -171,7 +171,7 @@ struct ConstPropMachine<'mir, 'tcx> {
     can_const_prop: IndexVec<Local, ConstPropMode>,
 }
 
-impl<'mir, 'tcx> ConstPropMachine<'mir, 'tcx> {
+impl ConstPropMachine<'_, '_> {
     fn new(
         only_propagate_inside_block_locals: BitSet<Local>,
         can_const_prop: IndexVec<Local, ConstPropMode>,
@@ -308,14 +308,14 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
     }
 
     #[inline(always)]
-    fn stack(
+    fn stack<'a>(
         ecx: &'a InterpCx<'mir, 'tcx, Self>,
     ) -> &'a [Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>] {
         &ecx.machine.stack
     }
 
     #[inline(always)]
-    fn stack_mut(
+    fn stack_mut<'a>(
         ecx: &'a mut InterpCx<'mir, 'tcx, Self>,
     ) -> &'a mut Vec<Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>> {
         &mut ecx.machine.stack
@@ -336,7 +336,7 @@ struct ConstPropagator<'mir, 'tcx> {
     source_info: Option<SourceInfo>,
 }
 
-impl<'mir, 'tcx> LayoutOfHelpers<'tcx> for ConstPropagator<'mir, 'tcx> {
+impl<'tcx> LayoutOfHelpers<'tcx> for ConstPropagator<'_, 'tcx> {
     type LayoutOfResult = Result<TyAndLayout<'tcx>, LayoutError<'tcx>>;
 
     #[inline]
@@ -345,21 +345,21 @@ impl<'mir, 'tcx> LayoutOfHelpers<'tcx> for ConstPropagator<'mir, 'tcx> {
     }
 }
 
-impl<'mir, 'tcx> HasDataLayout for ConstPropagator<'mir, 'tcx> {
+impl HasDataLayout for ConstPropagator<'_, '_> {
     #[inline]
     fn data_layout(&self) -> &TargetDataLayout {
         &self.tcx.data_layout
     }
 }
 
-impl<'mir, 'tcx> ty::layout::HasTyCtxt<'tcx> for ConstPropagator<'mir, 'tcx> {
+impl<'tcx> ty::layout::HasTyCtxt<'tcx> for ConstPropagator<'_, 'tcx> {
     #[inline]
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 }
 
-impl<'mir, 'tcx> ty::layout::HasParamEnv<'tcx> for ConstPropagator<'mir, 'tcx> {
+impl<'tcx> ty::layout::HasParamEnv<'tcx> for ConstPropagator<'_, 'tcx> {
     #[inline]
     fn param_env(&self) -> ty::ParamEnv<'tcx> {
         self.param_env
@@ -971,7 +971,7 @@ struct CanConstProp {
 
 impl CanConstProp {
     /// Returns true if `local` can be propagated
-    fn check(
+    fn check<'tcx>(
         tcx: TyCtxt<'tcx>,
         param_env: ParamEnv<'tcx>,
         body: &Body<'tcx>,
@@ -1019,7 +1019,7 @@ impl CanConstProp {
     }
 }
 
-impl<'tcx> Visitor<'tcx> for CanConstProp {
+impl Visitor<'_> for CanConstProp {
     fn visit_local(&mut self, &local: &Local, context: PlaceContext, _: Location) {
         use rustc_middle::mir::visit::PlaceContext::*;
         match context {
@@ -1079,7 +1079,7 @@ impl<'tcx> Visitor<'tcx> for CanConstProp {
     }
 }
 
-impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
+impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }

compiler/rustc_mir_transform/src/coverage/debug.rs

@@ -629,7 +629,7 @@ impl UsedExpressions {
 }
 
 /// Generates the MIR pass `CoverageSpan`-specific spanview dump file.
-pub(super) fn dump_coverage_spanview(
+pub(super) fn dump_coverage_spanview<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     basic_coverage_blocks: &CoverageGraph,
@@ -651,7 +651,7 @@ pub(super) fn dump_coverage_spanview(
 }
 
 /// Converts the computed `BasicCoverageBlockData`s into `SpanViewable`s.
-fn span_viewables(
+fn span_viewables<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     basic_coverage_blocks: &CoverageGraph,
@@ -670,7 +670,7 @@ fn span_viewables(
 }
 
 /// Generates the MIR pass coverage-specific graphviz dump file.
-pub(super) fn dump_coverage_graphviz(
+pub(super) fn dump_coverage_graphviz<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     pass_name: &str,
@@ -750,7 +750,7 @@ pub(super) fn dump_coverage_graphviz(
         .expect("Unexpected error writing BasicCoverageBlock graphviz DOT file");
 }
 
-fn bcb_to_string_sections(
+fn bcb_to_string_sections<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     debug_counters: &DebugCounters,
@@ -817,7 +817,7 @@ fn bcb_to_string_sections(
 
 /// Returns a simple string representation of a `TerminatorKind` variant, independent of any
 /// values it might hold.
-pub(super) fn term_type(kind: &TerminatorKind<'tcx>) -> &'static str {
+pub(super) fn term_type(kind: &TerminatorKind<'_>) -> &'static str {
     match kind {
         TerminatorKind::Goto { .. } => "Goto",
         TerminatorKind::SwitchInt { .. } => "SwitchInt",

compiler/rustc_mir_transform/src/coverage/graph.rs

@@ -27,7 +27,7 @@ pub(super) struct CoverageGraph {
 }
 
 impl CoverageGraph {
-    pub fn from_mir(mir_body: &mir::Body<'tcx>) -> Self {
+    pub fn from_mir(mir_body: &mir::Body<'_>) -> Self {
         let (bcbs, bb_to_bcb) = Self::compute_basic_coverage_blocks(mir_body);
 
         // Pre-transform MIR `BasicBlock` successors and predecessors into the BasicCoverageBlock
@@ -74,7 +74,7 @@ impl CoverageGraph {
     }
 
     fn compute_basic_coverage_blocks(
-        mir_body: &mir::Body<'tcx>,
+        mir_body: &mir::Body<'_>,
     ) -> (
         IndexVec<BasicCoverageBlock, BasicCoverageBlockData>,
         IndexVec<BasicBlock, Option<BasicCoverageBlock>>,
@@ -267,7 +267,7 @@ impl graph::WithSuccessors for CoverageGraph {
     }
 }
 
-impl graph::GraphPredecessors<'graph> for CoverageGraph {
+impl<'graph> graph::GraphPredecessors<'graph> for CoverageGraph {
     type Item = BasicCoverageBlock;
     type Iter = std::iter::Copied<std::slice::Iter<'graph, BasicCoverageBlock>>;
 }

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -443,7 +443,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
 }
 
 fn inject_edge_counter_basic_block(
-    mir_body: &mut mir::Body<'tcx>,
+    mir_body: &mut mir::Body<'_>,
     from_bb: BasicBlock,
     to_bb: BasicBlock,
 ) -> BasicBlock {
@@ -466,7 +466,7 @@ fn inject_edge_counter_basic_block(
 }
 
 fn inject_statement(
-    mir_body: &mut mir::Body<'tcx>,
+    mir_body: &mut mir::Body<'_>,
     counter_kind: CoverageKind,
     bb: BasicBlock,
     some_code_region: Option<CodeRegion>,
@@ -488,7 +488,7 @@ fn inject_statement(
 }
 
 // Non-code expressions are injected into the coverage map, without generating executable code.
-fn inject_intermediate_expression(mir_body: &mut mir::Body<'tcx>, expression: CoverageKind) {
+fn inject_intermediate_expression(mir_body: &mut mir::Body<'_>, expression: CoverageKind) {
     debug_assert!(matches!(expression, CoverageKind::Expression { .. }));
     debug!("  injecting non-code expression {:?}", expression);
     let inject_in_bb = mir::START_BLOCK;

compiler/rustc_mir_transform/src/coverage/query.rs

@@ -137,7 +137,7 @@ fn coverageinfo<'tcx>(tcx: TyCtxt<'tcx>, instance_def: ty::InstanceDef<'tcx>) ->
     coverage_visitor.info
 }
 
-fn covered_file_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<Symbol> {
+fn covered_file_name(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Symbol> {
     if tcx.is_mir_available(def_id) {
         let body = mir_body(tcx, def_id);
         for bb_data in body.basic_blocks().iter() {

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -21,7 +21,7 @@ pub(super) enum CoverageStatement {
 }
 
 impl CoverageStatement {
-    pub fn format(&self, tcx: TyCtxt<'tcx>, mir_body: &'a mir::Body<'tcx>) -> String {
+    pub fn format<'tcx>(&self, tcx: TyCtxt<'tcx>, mir_body: &mir::Body<'tcx>) -> String {
         match *self {
             Self::Statement(bb, span, stmt_index) => {
                 let stmt = &mir_body[bb].statements[stmt_index];
@@ -86,7 +86,7 @@ impl CoverageSpan {
     }
 
     pub fn for_statement(
-        statement: &Statement<'tcx>,
+        statement: &Statement<'_>,
         span: Span,
         expn_span: Span,
         bcb: BasicCoverageBlock,
@@ -151,7 +151,7 @@ impl CoverageSpan {
         self.bcb == other.bcb
     }
 
-    pub fn format(&self, tcx: TyCtxt<'tcx>, mir_body: &'a mir::Body<'tcx>) -> String {
+    pub fn format<'tcx>(&self, tcx: TyCtxt<'tcx>, mir_body: &mir::Body<'tcx>) -> String {
         format!(
             "{}\n    {}",
             source_range_no_file(tcx, &self.span),
@@ -159,10 +159,10 @@ impl CoverageSpan {
         )
     }
 
-    pub fn format_coverage_statements(
+    pub fn format_coverage_statements<'tcx>(
         &self,
         tcx: TyCtxt<'tcx>,
-        mir_body: &'a mir::Body<'tcx>,
+        mir_body: &mir::Body<'tcx>,
     ) -> String {
         let mut sorted_coverage_statements = self.coverage_statements.clone();
         sorted_coverage_statements.sort_unstable_by_key(|covstmt| match *covstmt {
@@ -803,7 +803,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
 
 /// If the MIR `Statement` has a span contributive to computing coverage spans,
 /// return it; otherwise return `None`.
-pub(super) fn filtered_statement_span(statement: &'a Statement<'tcx>) -> Option<Span> {
+pub(super) fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span> {
     match statement.kind {
         // These statements have spans that are often outside the scope of the executed source code
         // for their parent `BasicBlock`.
@@ -847,7 +847,7 @@ pub(super) fn filtered_statement_span(statement: &'a Statement<'tcx>) -> Option<
 
 /// If the MIR `Terminator` has a span contributive to computing coverage spans,
 /// return it; otherwise return `None`.
-pub(super) fn filtered_terminator_span(terminator: &'a Terminator<'tcx>) -> Option<Span> {
+pub(super) fn filtered_terminator_span(terminator: &Terminator<'_>) -> Option<Span> {
     match terminator.kind {
         // These terminators have spans that don't positively contribute to computing a reasonable
         // span of actually executed source code. (For example, SwitchInt terminators extracted from

compiler/rustc_mir_transform/src/coverage/tests.rs

@@ -180,7 +180,7 @@ impl<'tcx> MockBlocks<'tcx> {
     }
 }
 
-fn debug_basic_blocks(mir_body: &Body<'tcx>) -> String {
+fn debug_basic_blocks<'tcx>(mir_body: &Body<'tcx>) -> String {
     format!(
         "{:?}",
         mir_body
@@ -273,7 +273,7 @@ fn print_coverage_graphviz(
 }
 
 /// Create a mock `Body` with a simple flow.
-fn goto_switchint() -> Body<'a> {
+fn goto_switchint<'a>() -> Body<'a> {
     let mut blocks = MockBlocks::new();
     let start = blocks.call(None);
     let goto = blocks.goto(Some(start));
@@ -363,7 +363,7 @@ fn test_covgraph_goto_switchint() {
 }
 
 /// Create a mock `Body` with a loop.
-fn switchint_then_loop_else_return() -> Body<'a> {
+fn switchint_then_loop_else_return<'a>() -> Body<'a> {
     let mut blocks = MockBlocks::new();
     let start = blocks.call(None);
     let switchint = blocks.switchint(Some(start));
@@ -449,7 +449,7 @@ fn test_covgraph_switchint_then_loop_else_return() {
 }
 
 /// Create a mock `Body` with nested loops.
-fn switchint_loop_then_inner_loop_else_break() -> Body<'a> {
+fn switchint_loop_then_inner_loop_else_break<'a>() -> Body<'a> {
     let mut blocks = MockBlocks::new();
     let start = blocks.call(None);
     let switchint = blocks.switchint(Some(start));

compiler/rustc_mir_transform/src/deduplicate_blocks.rs

@@ -54,7 +54,7 @@ impl<'tcx> MutVisitor<'tcx> for OptApplier<'tcx> {
     }
 }
 
-fn find_duplicates<'a, 'tcx>(body: &'a Body<'tcx>) -> FxHashMap<BasicBlock, BasicBlock> {
+fn find_duplicates(body: &Body<'_>) -> FxHashMap<BasicBlock, BasicBlock> {
     let mut duplicates = FxHashMap::default();
 
     let bbs_to_go_through =
@@ -102,7 +102,7 @@ struct BasicBlockHashable<'tcx, 'a> {
     basic_block_data: &'a BasicBlockData<'tcx>,
 }
 
-impl<'tcx, 'a> Hash for BasicBlockHashable<'tcx, 'a> {
+impl Hash for BasicBlockHashable<'_, '_> {
     fn hash<H: Hasher>(&self, state: &mut H) {
         hash_statements(state, self.basic_block_data.statements.iter());
         // Note that since we only hash the kind, we lose span information if we deduplicate the blocks
@@ -110,9 +110,9 @@ impl<'tcx, 'a> Hash for BasicBlockHashable<'tcx, 'a> {
     }
 }
 
-impl<'tcx, 'a> Eq for BasicBlockHashable<'tcx, 'a> {}
+impl Eq for BasicBlockHashable<'_, '_> {}
 
-impl<'tcx, 'a> PartialEq for BasicBlockHashable<'tcx, 'a> {
+impl PartialEq for BasicBlockHashable<'_, '_> {
     fn eq(&self, other: &Self) -> bool {
         self.basic_block_data.statements.len() == other.basic_block_data.statements.len()
             && &self.basic_block_data.terminator().kind == &other.basic_block_data.terminator().kind
@@ -132,7 +132,7 @@ fn hash_statements<'a, 'tcx, H: Hasher>(
     }
 }
 
-fn statement_hash<'tcx, H: Hasher>(hasher: &mut H, stmt: &StatementKind<'tcx>) {
+fn statement_hash<H: Hasher>(hasher: &mut H, stmt: &StatementKind<'_>) {
     match stmt {
         StatementKind::Assign(box (place, rvalue)) => {
             place.hash(hasher);
@@ -142,14 +142,14 @@ fn statement_hash<'tcx, H: Hasher>(hasher: &mut H, stmt: &StatementKind<'tcx>) {
     };
 }
 
-fn rvalue_hash<H: Hasher>(hasher: &mut H, rvalue: &Rvalue<'tcx>) {
+fn rvalue_hash<H: Hasher>(hasher: &mut H, rvalue: &Rvalue<'_>) {
     match rvalue {
         Rvalue::Use(op) => operand_hash(hasher, op),
         x => x.hash(hasher),
     };
 }
 
-fn operand_hash<H: Hasher>(hasher: &mut H, operand: &Operand<'tcx>) {
+fn operand_hash<H: Hasher>(hasher: &mut H, operand: &Operand<'_>) {
     match operand {
         Operand::Constant(box Constant { user_ty: _, literal, span: _ }) => literal.hash(hasher),
         x => x.hash(hasher),
@@ -168,7 +168,7 @@ fn statement_eq<'tcx>(lhs: &StatementKind<'tcx>, rhs: &StatementKind<'tcx>) -> b
     res
 }
 
-fn rvalue_eq(lhs: &Rvalue<'tcx>, rhs: &Rvalue<'tcx>) -> bool {
+fn rvalue_eq<'tcx>(lhs: &Rvalue<'tcx>, rhs: &Rvalue<'tcx>) -> bool {
     let res = match (lhs, rhs) {
         (Rvalue::Use(op1), Rvalue::Use(op2)) => operand_eq(op1, op2),
         (x, y) => x == y,
@@ -177,7 +177,7 @@ fn rvalue_eq(lhs: &Rvalue<'tcx>, rhs: &Rvalue<'tcx>) -> bool {
     res
 }
 
-fn operand_eq(lhs: &Operand<'tcx>, rhs: &Operand<'tcx>) -> bool {
+fn operand_eq<'tcx>(lhs: &Operand<'tcx>, rhs: &Operand<'tcx>) -> bool {
     let res = match (lhs, rhs) {
         (
             Operand::Constant(box Constant { user_ty: _, literal, span: _ }),

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -241,7 +241,7 @@ struct Replacements<'tcx> {
     kill: BitSet<Local>,
 }
 
-impl Replacements<'tcx> {
+impl<'tcx> Replacements<'tcx> {
     fn new(locals: usize) -> Self {
         Self { map: IndexVec::from_elem_n(None, locals), kill: BitSet::new_empty(locals) }
     }
@@ -298,7 +298,7 @@ struct Replacer<'tcx> {
 }
 
 impl<'tcx> MutVisitor<'tcx> for Replacer<'tcx> {
-    fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 
@@ -372,7 +372,7 @@ struct Conflicts<'a> {
     unified_locals: InPlaceUnificationTable<UnifyLocal>,
 }
 
-impl Conflicts<'a> {
+impl<'a> Conflicts<'a> {
     fn build<'tcx>(
         tcx: TyCtxt<'tcx>,
         body: &'_ Body<'tcx>,
@@ -820,10 +820,7 @@ struct CandidateAssignment<'tcx> {
 /// comment) and also throw out assignments that involve a local that has its address taken or is
 /// otherwise ineligible (eg. locals used as array indices are ignored because we cannot propagate
 /// arbitrary places into array indices).
-fn find_candidates<'a, 'tcx>(
+fn find_candidates<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) -> Vec<CandidateAssignment<'tcx>> {
-    tcx: TyCtxt<'tcx>,
-    body: &'a Body<'tcx>,
-) -> Vec<CandidateAssignment<'tcx>> {
     let mut visitor = FindAssignments {
         tcx,
         body,
@@ -843,7 +840,7 @@ struct FindAssignments<'a, 'tcx> {
     locals_used_as_array_index: BitSet<Local>,
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for FindAssignments<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for FindAssignments<'_, 'tcx> {
     fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
         if let StatementKind::Assign(box (
             dest,

compiler/rustc_mir_transform/src/early_otherwise_branch.rs

@@ -167,7 +167,7 @@ impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
     }
 }
 
-fn is_switch<'tcx>(terminator: &Terminator<'tcx>) -> bool {
+fn is_switch(terminator: &Terminator<'_>) -> bool {
     matches!(terminator.kind, TerminatorKind::SwitchInt { .. })
 }
 
@@ -208,7 +208,7 @@ struct OptimizationInfo<'tcx> {
     second_switch_info: SwitchDiscriminantInfo<'tcx>,
 }
 
-impl<'a, 'tcx> Helper<'a, 'tcx> {
+impl<'tcx> Helper<'_, 'tcx> {
     pub fn go(
         &self,
         bb: &BasicBlockData<'tcx>,

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -149,13 +149,13 @@ struct Elaborator<'a, 'b, 'tcx> {
     ctxt: &'a mut ElaborateDropsCtxt<'b, 'tcx>,
 }
 
-impl<'a, 'b, 'tcx> fmt::Debug for Elaborator<'a, 'b, 'tcx> {
+impl fmt::Debug for Elaborator<'_, '_, '_> {
     fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Ok(())
     }
 }
 
-impl<'a, 'b, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, 'b, 'tcx> {
+impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, 'tcx> {
     type Path = MovePathIndex;
 
     fn patch(&mut self) -> &mut MirPatch<'tcx> {

compiler/rustc_mir_transform/src/function_item_references.rs

@@ -27,7 +27,7 @@ struct FunctionItemRefChecker<'a, 'tcx> {
     body: &'a Body<'tcx>,
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for FunctionItemRefChecker<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for FunctionItemRefChecker<'_, 'tcx> {
     /// Emits a lint for function reference arguments bound by `fmt::Pointer` or passed to
     /// `transmute`. This only handles arguments in calls outside macro expansions to avoid double
     /// counting function references formatted as pointers by macros.
@@ -92,7 +92,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FunctionItemRefChecker<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> FunctionItemRefChecker<'a, 'tcx> {
+impl<'tcx> FunctionItemRefChecker<'_, 'tcx> {
     /// Emits a lint for function reference arguments bound by `fmt::Pointer` in calls to the
     /// function defined by `def_id` with the substitutions `substs_ref`.
     fn check_bound_args(

compiler/rustc_mir_transform/src/generator.rs

@@ -233,7 +233,7 @@ struct TransformVisitor<'tcx> {
     new_ret_local: Local,
 }
 
-impl TransformVisitor<'tcx> {
+impl<'tcx> TransformVisitor<'tcx> {
     // Make a GeneratorState variant assignment. `core::ops::GeneratorState` only has single
     // element tuple variants, so we can just write to the downcasted first field and then set the
     // discriminant to the appropriate variant.
@@ -295,7 +295,7 @@ impl TransformVisitor<'tcx> {
     }
 }
 
-impl MutVisitor<'tcx> for TransformVisitor<'tcx> {
+impl<'tcx> MutVisitor<'tcx> for TransformVisitor<'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
@@ -446,7 +446,7 @@ struct LivenessInfo {
     storage_liveness: IndexVec<BasicBlock, Option<BitSet<Local>>>,
 }
 
-fn locals_live_across_suspend_points(
+fn locals_live_across_suspend_points<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
     always_live_locals: &storage::AlwaysLiveLocals,
@@ -613,7 +613,7 @@ impl ops::Deref for GeneratorSavedLocals {
 /// time. Generates a bitset for every local of all the other locals that may be
 /// StorageLive simultaneously with that local. This is used in the layout
 /// computation; see `GeneratorLayout` for more.
-fn compute_storage_conflicts(
+fn compute_storage_conflicts<'mir, 'tcx>(
     body: &'mir Body<'tcx>,
     saved_locals: &GeneratorSavedLocals,
     always_live_locals: storage::AlwaysLiveLocals,
@@ -672,7 +672,9 @@ struct StorageConflictVisitor<'mir, 'tcx, 's> {
     local_conflicts: BitMatrix<Local, Local>,
 }
 
-impl rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx> for StorageConflictVisitor<'mir, 'tcx, '_> {
+impl<'mir, 'tcx> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx>
+    for StorageConflictVisitor<'mir, 'tcx, '_>
+{
     type FlowState = BitSet<Local>;
 
     fn visit_statement_before_primary_effect(
@@ -694,7 +696,7 @@ impl rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx> for StorageConflictVisitor<'
     }
 }
 
-impl<'body, 'tcx, 's> StorageConflictVisitor<'body, 'tcx, 's> {
+impl StorageConflictVisitor<'_, '_, '_> {
     fn apply_state(&mut self, flow_state: &BitSet<Local>, loc: Location) {
         // Ignore unreachable blocks.
         if self.body.basic_blocks()[loc.block].terminator().kind == TerminatorKind::Unreachable {
@@ -1398,7 +1400,7 @@ impl EnsureGeneratorFieldAssignmentsNeverAlias<'_> {
         self.saved_locals.get(place.local)
     }
 
-    fn check_assigned_place(&mut self, place: Place<'tcx>, f: impl FnOnce(&mut Self)) {
+    fn check_assigned_place(&mut self, place: Place<'_>, f: impl FnOnce(&mut Self)) {
         if let Some(assigned_local) = self.saved_local_for_direct_place(place) {
             assert!(self.assigned_local.is_none(), "`check_assigned_place` must not recurse");
 
@@ -1409,7 +1411,7 @@ impl EnsureGeneratorFieldAssignmentsNeverAlias<'_> {
     }
 }
 
-impl Visitor<'tcx> for EnsureGeneratorFieldAssignmentsNeverAlias<'_> {
+impl<'tcx> Visitor<'tcx> for EnsureGeneratorFieldAssignmentsNeverAlias<'_> {
     fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
         let lhs = match self.assigned_local {
             Some(l) => l,

compiler/rustc_mir_transform/src/inline.rs

@@ -57,7 +57,7 @@ impl<'tcx> MirPass<'tcx> for Inline {
     }
 }
 
-fn inline(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
+fn inline<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
     let def_id = body.source.def_id();
     let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
 
@@ -95,7 +95,7 @@ struct Inliner<'tcx> {
     changed: bool,
 }
 
-impl Inliner<'tcx> {
+impl<'tcx> Inliner<'tcx> {
     fn process_blocks(&mut self, caller_body: &mut Body<'tcx>, blocks: Range<BasicBlock>) {
         for bb in blocks {
             let bb_data = &caller_body[bb];
@@ -786,7 +786,7 @@ struct Integrator<'a, 'tcx> {
     always_live_locals: BitSet<Local>,
 }
 
-impl<'a, 'tcx> Integrator<'a, 'tcx> {
+impl Integrator<'_, '_> {
     fn map_local(&self, local: Local) -> Local {
         let new = if local == RETURN_PLACE {
             self.destination.local
@@ -815,7 +815,7 @@ impl<'a, 'tcx> Integrator<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
+impl<'tcx> MutVisitor<'tcx> for Integrator<'_, 'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }

compiler/rustc_mir_transform/src/inline/cycle.rs

@@ -10,7 +10,7 @@ use rustc_session::Limit;
 // FIXME: check whether it is cheaper to precompute the entire call graph instead of invoking
 // this query riddiculously often.
 #[instrument(level = "debug", skip(tcx, root, target))]
-crate fn mir_callgraph_reachable(
+crate fn mir_callgraph_reachable<'tcx>(
     tcx: TyCtxt<'tcx>,
     (root, target): (ty::Instance<'tcx>, LocalDefId),
 ) -> bool {
@@ -33,7 +33,7 @@ crate fn mir_callgraph_reachable(
         level = "debug",
         skip(tcx, param_env, target, stack, seen, recursion_limiter, caller, recursion_limit)
     )]
-    fn process(
+    fn process<'tcx>(
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         caller: ty::Instance<'tcx>,

compiler/rustc_mir_transform/src/instcombine.rs

@@ -38,7 +38,7 @@ struct InstCombineContext<'tcx, 'a> {
     local_decls: &'a LocalDecls<'tcx>,
 }
 
-impl<'tcx, 'a> InstCombineContext<'tcx, 'a> {
+impl<'tcx> InstCombineContext<'tcx, '_> {
     fn should_combine(&self, source_info: &SourceInfo, rvalue: &Rvalue<'tcx>) -> bool {
         self.tcx.consider_optimizing(|| {
             format!("InstCombine - Rvalue: {:?} SourceInfo: {:?}", rvalue, source_info)

compiler/rustc_mir_transform/src/lib.rs

@@ -1,7 +1,6 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(crate_visibility_modifier)]
-#![feature(in_band_lifetimes)]
 #![feature(iter_zip)]
 #![feature(let_else)]
 #![feature(map_try_insert)]
@@ -150,7 +149,7 @@ fn mir_keys(tcx: TyCtxt<'_>, (): ()) -> FxHashSet<LocalDefId> {
         tcx: TyCtxt<'tcx>,
         set: &'a mut FxHashSet<LocalDefId>,
     }
-    impl<'a, 'tcx> Visitor<'tcx> for GatherCtors<'a, 'tcx> {
+    impl<'tcx> Visitor<'tcx> for GatherCtors<'_, 'tcx> {
         fn visit_variant_data(
             &mut self,
             v: &'tcx hir::VariantData<'tcx>,
@@ -243,7 +242,7 @@ fn mir_const<'tcx>(
 }
 
 /// Compute the main MIR body and the list of MIR bodies of the promoteds.
-fn mir_promoted(
+fn mir_promoted<'tcx>(
     tcx: TyCtxt<'tcx>,
     def: ty::WithOptConstParam<LocalDefId>,
 ) -> (&'tcx Steal<Body<'tcx>>, &'tcx Steal<IndexVec<Promoted, Body<'tcx>>>) {

compiler/rustc_mir_transform/src/lower_intrinsics.rs

@@ -135,7 +135,7 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
     }
 }
 
-fn resolve_rust_intrinsic(
+fn resolve_rust_intrinsic<'tcx>(
     tcx: TyCtxt<'tcx>,
     func_ty: Ty<'tcx>,
 ) -> Option<(Symbol, SubstsRef<'tcx>)> {
@@ -148,7 +148,7 @@ fn resolve_rust_intrinsic(
     None
 }
 
-fn validate_simd_shuffle(tcx: TyCtxt<'tcx>, args: &[Operand<'tcx>], span: Span) {
+fn validate_simd_shuffle<'tcx>(tcx: TyCtxt<'tcx>, args: &[Operand<'tcx>], span: Span) {
     match &args[2] {
         Operand::Constant(_) => {} // all good
         _ => {

compiler/rustc_mir_transform/src/normalize_array_len.rs

@@ -85,7 +85,7 @@ struct Patcher<'a, 'tcx> {
     statement_idx: usize,
 }
 
-impl<'a, 'tcx> Patcher<'a, 'tcx> {
+impl<'tcx> Patcher<'_, 'tcx> {
     fn patch_expand_statement(
         &mut self,
         statement: &mut Statement<'tcx>,

compiler/rustc_mir_transform/src/nrvo.rs

@@ -165,7 +165,7 @@ struct RenameToReturnPlace<'tcx> {
 }
 
 /// Replaces all uses of `self.to_rename` with `_0`.
-impl MutVisitor<'tcx> for RenameToReturnPlace<'tcx> {
+impl<'tcx> MutVisitor<'tcx> for RenameToReturnPlace<'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
@@ -221,7 +221,7 @@ impl IsReturnPlaceRead {
     }
 }
 
-impl Visitor<'tcx> for IsReturnPlaceRead {
+impl<'tcx> Visitor<'tcx> for IsReturnPlaceRead {
     fn visit_local(&mut self, &l: &Local, ctxt: PlaceContext, _: Location) {
         if l == mir::RETURN_PLACE && ctxt.is_use() && !ctxt.is_place_assignment() {
             self.0 = true;

compiler/rustc_mir_transform/src/pass_manager.rs

@@ -28,7 +28,7 @@ pub trait MirLint<'tcx> {
 #[derive(Debug, Clone)]
 pub struct Lint<T>(pub T);
 
-impl<T> MirPass<'tcx> for Lint<T>
+impl<'tcx, T> MirPass<'tcx> for Lint<T>
 where
     T: MirLint<'tcx>,
 {
@@ -51,7 +51,7 @@ where
 
 pub struct WithMinOptLevel<T>(pub u32, pub T);
 
-impl<T> MirPass<'tcx> for WithMinOptLevel<T>
+impl<'tcx, T> MirPass<'tcx> for WithMinOptLevel<T>
 where
     T: MirPass<'tcx>,
 {
@@ -72,7 +72,7 @@ where
     }
 }
 
-pub fn run_passes(tcx: TyCtxt<'tcx>, body: &'mir mut Body<'tcx>, passes: &[&dyn MirPass<'tcx>]) {
+pub fn run_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, passes: &[&dyn MirPass<'tcx>]) {
     let start_phase = body.phase;
     let mut cnt = 0;
 
@@ -119,11 +119,11 @@ pub fn run_passes(tcx: TyCtxt<'tcx>, body: &'mir mut Body<'tcx>, passes: &[&dyn
     }
 }
 
-pub fn validate_body(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, when: String) {
+pub fn validate_body<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, when: String) {
     validate::Validator { when, mir_phase: body.phase }.run_pass(tcx, body);
 }
 
-pub fn dump_mir(
+pub fn dump_mir<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
     phase: MirPhase,

compiler/rustc_mir_transform/src/remove_uninit_drops.rs

@@ -86,7 +86,7 @@ impl<'tcx> MirPass<'tcx> for RemoveUninitDrops {
     }
 }
 
-fn is_needs_drop_and_init(
+fn is_needs_drop_and_init<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
     maybe_inits: &BitSet<MovePathIndex>,
@@ -158,7 +158,7 @@ fn is_needs_drop_and_init(
     }
 }
 
-fn variant_needs_drop(
+fn variant_needs_drop<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
     substs: SubstsRef<'tcx>,

compiler/rustc_mir_transform/src/required_consts.rs

@@ -12,7 +12,7 @@ impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for RequiredConstsVisitor<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for RequiredConstsVisitor<'_, 'tcx> {
     fn visit_constant(&mut self, constant: &Constant<'tcx>, _: Location) {
         if let Some(ct) = constant.literal.const_for_ty() {
             if let ConstKind::Unevaluated(_) = ct.val {

compiler/rustc_mir_transform/src/separate_const_switch.rs

@@ -59,7 +59,7 @@ impl<'tcx> MirPass<'tcx> for SeparateConstSwitch {
 }
 
 /// Returns the amount of blocks that were duplicated
-pub fn separate_const_switch<'tcx>(body: &mut Body<'tcx>) -> usize {
+pub fn separate_const_switch(body: &mut Body<'_>) -> usize {
     let mut new_blocks: SmallVec<[(BasicBlock, BasicBlock); 6]> = SmallVec::new();
     let predecessors = body.predecessors();
     'block_iter: for (block_id, block) in body.basic_blocks().iter_enumerated() {

compiler/rustc_mir_transform/src/shim.rs

@@ -247,7 +247,7 @@ pub struct DropShimElaborator<'a, 'tcx> {
     pub param_env: ty::ParamEnv<'tcx>,
 }
 
-impl<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> {
+impl fmt::Debug for DropShimElaborator<'_, '_> {
     fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
         Ok(())
     }
@@ -337,7 +337,7 @@ struct CloneShimBuilder<'tcx> {
     sig: ty::FnSig<'tcx>,
 }
 
-impl CloneShimBuilder<'tcx> {
+impl<'tcx> CloneShimBuilder<'tcx> {
     fn new(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Self {
         // we must subst the self_ty because it's
         // otherwise going to be TySelf and we can't index

compiler/rustc_mir_transform/src/simplify.rs

@@ -47,7 +47,7 @@ impl SimplifyCfg {
     }
 }
 
-pub fn simplify_cfg(tcx: TyCtxt<'tcx>, body: &mut Body<'_>) {
+pub fn simplify_cfg<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     CfgSimplifier::new(body).simplify();
     remove_dead_blocks(tcx, body);
 
@@ -262,7 +262,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
     }
 }
 
-pub fn remove_dead_blocks(tcx: TyCtxt<'tcx>, body: &mut Body<'_>) {
+pub fn remove_dead_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let reachable = traversal::reachable_as_bitset(body);
     let num_blocks = body.basic_blocks().len();
     if num_blocks == reachable.count() {
@@ -454,7 +454,7 @@ impl UsedLocals {
     }
 
     /// Updates the use counts to reflect the removal of given statement.
-    fn statement_removed(&mut self, statement: &Statement<'tcx>) {
+    fn statement_removed(&mut self, statement: &Statement<'_>) {
         self.increment = false;
 
         // The location of the statement is irrelevant.
@@ -463,7 +463,7 @@ impl UsedLocals {
     }
 
     /// Visits a left-hand side of an assignment.
-    fn visit_lhs(&mut self, place: &Place<'tcx>, location: Location) {
+    fn visit_lhs(&mut self, place: &Place<'_>, location: Location) {
         if place.is_indirect() {
             // A use, not a definition.
             self.visit_place(place, PlaceContext::MutatingUse(MutatingUseContext::Store), location);
@@ -480,7 +480,7 @@ impl UsedLocals {
     }
 }
 
-impl Visitor<'_> for UsedLocals {
+impl<'tcx> Visitor<'tcx> for UsedLocals {
     fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
         match statement.kind {
             StatementKind::LlvmInlineAsm(..)
@@ -518,7 +518,7 @@ impl Visitor<'_> for UsedLocals {
 }
 
 /// Removes unused definitions. Updates the used locals to reflect the changes made.
-fn remove_unused_definitions<'a, 'tcx>(used_locals: &'a mut UsedLocals, body: &mut Body<'tcx>) {
+fn remove_unused_definitions(used_locals: &mut UsedLocals, body: &mut Body<'_>) {
     // The use counts are updated as we remove the statements. A local might become unused
     // during the retain operation, leading to a temporary inconsistency (storage statements or
     // definitions referencing the local might remain). For correctness it is crucial that this

compiler/rustc_mir_transform/src/simplify_comparison_integral.rs

@@ -148,7 +148,7 @@ struct OptimizationFinder<'a, 'tcx> {
     body: &'a Body<'tcx>,
 }
 
-impl<'a, 'tcx> OptimizationFinder<'a, 'tcx> {
+impl<'tcx> OptimizationFinder<'_, 'tcx> {
     fn find_optimizations(&self) -> Vec<OptimizationInfo<'tcx>> {
         self.body
             .basic_blocks()

compiler/rustc_mir_transform/src/simplify_try.rs

@@ -102,7 +102,7 @@ fn get_arm_identity_info<'a, 'tcx>(
 
     type StmtIter<'a, 'tcx> = Peekable<Enumerate<Iter<'a, Statement<'tcx>>>>;
 
-    fn is_storage_stmt<'tcx>(stmt: &Statement<'tcx>) -> bool {
+    fn is_storage_stmt(stmt: &Statement<'_>) -> bool {
         matches!(stmt.kind, StatementKind::StorageLive(_) | StatementKind::StorageDead(_))
     }
 
@@ -122,8 +122,8 @@ fn get_arm_identity_info<'a, 'tcx>(
 
     /// Eats consecutive `StorageLive` and `StorageDead` Statements.
     /// The iterator `stmt_iter` is not advanced if none were found.
-    fn try_eat_storage_stmts<'a, 'tcx>(
+    fn try_eat_storage_stmts(
-        stmt_iter: &mut StmtIter<'a, 'tcx>,
+        stmt_iter: &mut StmtIter<'_, '_>,
         storage_live_stmts: &mut Vec<(usize, Local)>,
         storage_dead_stmts: &mut Vec<(usize, Local)>,
     ) {
@@ -136,7 +136,7 @@ fn get_arm_identity_info<'a, 'tcx>(
         })
     }
 
-    fn is_tmp_storage_stmt<'tcx>(stmt: &Statement<'tcx>) -> bool {
+    fn is_tmp_storage_stmt(stmt: &Statement<'_>) -> bool {
         use rustc_middle::mir::StatementKind::Assign;
         if let Assign(box (place, Rvalue::Use(Operand::Copy(p) | Operand::Move(p)))) = &stmt.kind {
             place.as_local().is_some() && p.as_local().is_some()
@@ -147,8 +147,8 @@ fn get_arm_identity_info<'a, 'tcx>(
 
     /// Eats consecutive `Assign` Statements.
     // The iterator `stmt_iter` is not advanced if none were found.
-    fn try_eat_assign_tmp_stmts<'a, 'tcx>(
+    fn try_eat_assign_tmp_stmts(
-        stmt_iter: &mut StmtIter<'a, 'tcx>,
+        stmt_iter: &mut StmtIter<'_, '_>,
         tmp_assigns: &mut Vec<(Local, Local)>,
         nop_stmts: &mut Vec<usize>,
     ) {
@@ -163,9 +163,9 @@ fn get_arm_identity_info<'a, 'tcx>(
         })
     }
 
-    fn find_storage_live_dead_stmts_for_local<'tcx>(
+    fn find_storage_live_dead_stmts_for_local(
         local: Local,
-        stmts: &[Statement<'tcx>],
+        stmts: &[Statement<'_>],
     ) -> Option<(usize, usize)> {
         trace!("looking for {:?}", local);
         let mut storage_live_stmt = None;
@@ -452,14 +452,14 @@ struct LocalUseCounter {
 }
 
 impl LocalUseCounter {
-    fn get_local_uses<'tcx>(body: &Body<'tcx>) -> IndexVec<Local, usize> {
+    fn get_local_uses(body: &Body<'_>) -> IndexVec<Local, usize> {
         let mut counter = LocalUseCounter { local_uses: IndexVec::from_elem(0, &body.local_decls) };
         counter.visit_body(body);
         counter.local_uses
     }
 }
 
-impl<'tcx> Visitor<'tcx> for LocalUseCounter {
+impl Visitor<'_> for LocalUseCounter {
     fn visit_local(&mut self, local: &Local, context: PlaceContext, _location: Location) {
         if context.is_storage_marker()
             || context == PlaceContext::NonUse(NonUseContext::VarDebugInfo)
@@ -510,7 +510,7 @@ fn match_set_variant_field<'tcx>(stmt: &Statement<'tcx>) -> Option<(Local, Local
 /// ```rust
 /// discriminant(_LOCAL_TO_SET) = VAR_IDX;
 /// ```
-fn match_set_discr<'tcx>(stmt: &Statement<'tcx>) -> Option<(Local, VariantIdx)> {
+fn match_set_discr(stmt: &Statement<'_>) -> Option<(Local, VariantIdx)> {
     match &stmt.kind {
         StatementKind::SetDiscriminant { place, variant_index } => {
             Some((place.as_local()?, *variant_index))
@@ -588,7 +588,7 @@ struct SimplifyBranchSameOptimizationFinder<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
 }
 
-impl<'a, 'tcx> SimplifyBranchSameOptimizationFinder<'a, 'tcx> {
+impl<'tcx> SimplifyBranchSameOptimizationFinder<'_, 'tcx> {
     fn find(&self) -> Vec<SimplifyBranchSameOptimization> {
         self.body
             .basic_blocks()

compiler/rustc_mir_transform/src/unreachable_prop.rs

@@ -64,7 +64,7 @@ impl MirPass<'_> for UnreachablePropagation {
     }
 }
 
-fn remove_successors<F>(
+fn remove_successors<'tcx, F>(
     terminator_kind: &TerminatorKind<'tcx>,
     predicate: F,
 ) -> Option<TerminatorKind<'tcx>>