Remove unnecessary lifetime in PlaceCollector.

Author: nnethercote

compiler/rustc_mir_dataflow/src/value_analysis.rs

@@ -923,14 +923,14 @@ impl<'tcx> Map<'tcx> {
 }
 }
 
-structPlaceCollector<'a,'b,'tcx>{
+structPlaceCollector<'a,'tcx>{
 tcx:TyCtxt<'tcx>,
-body:&'bBody<'tcx>,
+body:&'aBody<'tcx>,
 map:&'amutMap<'tcx>,
 assignments:FxIndexSet<(PlaceIndex,PlaceIndex)>,
 }
 
-impl<'tcx>PlaceCollector<'_,'_,'tcx>{
+impl<'tcx>PlaceCollector<'_,'tcx>{
 #[tracing::instrument(level = "trace", skip(self))]
 fnregister_place(&mutself,place:Place<'tcx>) -> Option<PlaceIndex>{
 // Create a place for this projection.
@@ -967,7 +967,7 @@ impl<'tcx> PlaceCollector<'_, '_, 'tcx> {
 }
 }
 
-impl<'tcx>Visitor<'tcx>forPlaceCollector<'_,'_,'tcx>{
+impl<'tcx>Visitor<'tcx>forPlaceCollector<'_,'tcx>{
 #[tracing::instrument(level = "trace", skip(self))]
 fnvisit_place(&mutself,place:&Place<'tcx>,ctxt:PlaceContext, _:Location){
 if !ctxt.is_use(){