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_trait_selection/src/traits/query/normalize.rs

@@ -25,7 +25,7 @@ use crate::traits::{
 };
 
 #[extension(pub trait QueryNormalizeExt<'tcx>)]
-impl<'cx, 'tcx> At<'cx, 'tcx> {
+impl<'a, 'tcx> At<'a, 'tcx> {
     /// Normalize `value` in the context of the inference context,
     /// yielding a resulting type, or an error if `value` cannot be
     /// normalized. If you don't care about regions, you should prefer
@@ -160,9 +160,9 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for MaxEscapingBoundVarVisitor {
     }
 }
 
-struct QueryNormalizer<'cx, 'tcx> {
-    infcx: &'cx InferCtxt<'tcx>,
-    cause: &'cx ObligationCause<'tcx>,
+struct QueryNormalizer<'a, 'tcx> {
+    infcx: &'a InferCtxt<'tcx>,
+    cause: &'a ObligationCause<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     obligations: Vec<PredicateObligation<'tcx>>,
     cache: SsoHashMap<Ty<'tcx>, Ty<'tcx>>,
@@ -170,7 +170,7 @@ struct QueryNormalizer<'cx, 'tcx> {
     universes: Vec<Option<ty::UniverseIndex>>,
 }
 
-impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx> {
+impl<'a, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'a, 'tcx> {
     type Error = NoSolution;
 
     fn cx(&self) -> TyCtxt<'tcx> {