Check const Drop impls considering ConstIfConst bounds

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1153,7 +1153,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     GeneratorCandidate => {}
                     // FnDef where the function is const
                     FnPointerCandidate { is_const: true } => {}
-                    ConstDropCandidate => {}
+                    ConstDropCandidate(_) => {}
                     _ => {
                         // reject all other types of candidates
                         continue;
@@ -1537,7 +1537,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         };
 
         // (*) Prefer `BuiltinCandidate { has_nested: false }`, `PointeeCandidate`,
-        // and `DiscriminantKindCandidate` to anything else.
+        // `DiscriminantKindCandidate`, and `ConstDropCandidate` to anything else.
         //
         // This is a fix for #53123 and prevents winnowing from accidentally extending the
         // lifetime of a variable.
@@ -1554,7 +1554,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 BuiltinCandidate { has_nested: false }
                 | DiscriminantKindCandidate
                 | PointeeCandidate
-                | ConstDropCandidate,
+                | ConstDropCandidate(_),
                 _,
             ) => true,
             (
@@ -1562,7 +1562,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 BuiltinCandidate { has_nested: false }
                 | DiscriminantKindCandidate
                 | PointeeCandidate
-                | ConstDropCandidate,
+                | ConstDropCandidate(_),
             ) => false,
 
             (ParamCandidate(other), ParamCandidate(victim)) => {