Rename and reorder lots of lifetimes.

- Replace non-standard names like 's, 'p, 'rg, 'ck, 'parent, 'this, and
  'me with vanilla 'a. These are cases where the original name isn't
  really any more informative than 'a.
- Replace names like 'cx, 'mir, and 'body with vanilla 'a when the lifetime
  applies to multiple fields and so the original lifetime name isn't
  really accurate.
- Put 'tcx last in lifetime lists, and 'a before 'b.

compiler/rustc_lint/src/tail_expr_drop_order.rs

@@ -143,18 +143,18 @@ impl<'tcx> LateLintPass<'tcx> for TailExprDropOrder {
     }
 }
 
-struct LintVisitor<'tcx, 'a> {
+struct LintVisitor<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     // We only record locals that have significant drops
     locals: Vec<Span>,
 }
 
-struct LocalCollector<'tcx, 'a> {
+struct LocalCollector<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     locals: &'a mut Vec<Span>,
 }
 
-impl<'tcx, 'a> Visitor<'tcx> for LocalCollector<'tcx, 'a> {
+impl<'a, 'tcx> Visitor<'tcx> for LocalCollector<'a, 'tcx> {
     type Result = ();
     fn visit_pat(&mut self, pat: &'tcx Pat<'tcx>) {
         if let PatKind::Binding(_binding_mode, id, ident, pat) = pat.kind {
@@ -171,7 +171,7 @@ impl<'tcx, 'a> Visitor<'tcx> for LocalCollector<'tcx, 'a> {
     }
 }
 
-impl<'tcx, 'a> Visitor<'tcx> for LintVisitor<'tcx, 'a> {
+impl<'a, 'tcx> Visitor<'tcx> for LintVisitor<'a, 'tcx> {
     fn visit_block(&mut self, block: &'tcx Block<'tcx>) {
         let mut locals = <_>::default();
         swap(&mut locals, &mut self.locals);
@@ -183,7 +183,7 @@ impl<'tcx, 'a> Visitor<'tcx> for LintVisitor<'tcx, 'a> {
     }
 }
 
-impl<'tcx, 'a> LintVisitor<'tcx, 'a> {
+impl<'a, 'tcx> LintVisitor<'a, 'tcx> {
     fn check_block_inner(&mut self, block: &Block<'tcx>) {
         if !block.span.at_least_rust_2024() {
             // We only lint for Edition 2024 onwards
@@ -205,13 +205,13 @@ impl<'tcx, 'a> LintVisitor<'tcx, 'a> {
     }
 }
 
-struct LintTailExpr<'tcx, 'a> {
+struct LintTailExpr<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     is_root_tail_expr: bool,
     locals: &'a [Span],
 }
 
-impl<'tcx, 'a> LintTailExpr<'tcx, 'a> {
+impl<'a, 'tcx> LintTailExpr<'a, 'tcx> {
     fn expr_eventually_point_into_local(mut expr: &Expr<'tcx>) -> bool {
         loop {
             match expr.kind {
@@ -239,7 +239,7 @@ impl<'tcx, 'a> LintTailExpr<'tcx, 'a> {
     }
 }
 
-impl<'tcx, 'a> Visitor<'tcx> for LintTailExpr<'tcx, 'a> {
+impl<'a, 'tcx> Visitor<'tcx> for LintTailExpr<'a, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
         if self.is_root_tail_expr {
             self.is_root_tail_expr = false;

compiler/rustc_lint/src/types.rs

@@ -1713,13 +1713,13 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
         hir_ty: &hir::Ty<'tcx>,
         ty: Ty<'tcx>,
     ) -> Vec<(Ty<'tcx>, Span)> {
-        struct FnPtrFinder<'parent, 'a, 'tcx> {
-            visitor: &'parent ImproperCTypesVisitor<'a, 'tcx>,
+        struct FnPtrFinder<'a, 'b, 'tcx> {
+            visitor: &'a ImproperCTypesVisitor<'b, 'tcx>,
             spans: Vec<Span>,
             tys: Vec<Ty<'tcx>>,
         }
 
-        impl<'parent, 'a, 'tcx> hir::intravisit::Visitor<'_> for FnPtrFinder<'parent, 'a, 'tcx> {
+        impl<'a, 'b, 'tcx> hir::intravisit::Visitor<'_> for FnPtrFinder<'a, 'b, 'tcx> {
             fn visit_ty(&mut self, ty: &'_ hir::Ty<'_>) {
                 debug!(?ty);
                 if let hir::TyKind::BareFn(hir::BareFnTy { abi, .. }) = ty.kind
@@ -1732,7 +1732,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
             }
         }
 
-        impl<'vis, 'a, 'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for FnPtrFinder<'vis, 'a, 'tcx> {
+        impl<'a, 'b, 'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for FnPtrFinder<'a, 'b, 'tcx> {
             type Result = ControlFlow<Ty<'tcx>>;
 
             fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
@@ -1746,7 +1746,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
             }
         }
 
-        let mut visitor = FnPtrFinder { visitor: &*self, spans: Vec::new(), tys: Vec::new() };
+        let mut visitor = FnPtrFinder { visitor: self, spans: Vec::new(), tys: Vec::new() };
         ty.visit_with(&mut visitor);
         hir::intravisit::Visitor::visit_ty(&mut visitor, hir_ty);