Rollup merge of #77754 - bugadani:find_map_relevant_impl, r=matthewjasper

Add TraitDef::find_map_relevant_impl

This PR adds a method to `TraitDef`. While `for_each_relevant_impl` covers the general use case, sometimes it's not necessary to scan through all the relevant implementations, so this PR introduces a new method, `find_map_relevant_impl`. I've also replaced the `for_each_relevant_impl` calls where possible.

I'm hoping for a tiny bit of efficiency gain here and there.

1 files changed, 1 insertions, 2 deletions

diff --git a/compiler/rustc_mir/src/transform/check_const_item_mutation.rs b/compiler/rustc_mir/src/transform/check_const_item_mutation.rs
index 4d4e9b98917..26993a6b941 100644
--- a/compiler/rustc_mir/src/transform/check_const_item_mutation.rs
+++ b/compiler/rustc_mir/src/transform/check_const_item_mutation.rs
@@ -34,7 +34,6 @@ impl<'a, 'tcx> ConstMutationChecker<'a, 'tcx> {
 
     fn is_const_item_without_destructor(&self, local: Local) -> Option<DefId> {
         let def_id = self.is_const_item(local)?;
-        let mut any_dtor = |_tcx, _def_id| Ok(());
 
         // We avoid linting mutation of a const item if the const's type has a
         // Drop impl. The Drop logic observes the mutation which was performed.
@@ -54,7 +53,7 @@ impl<'a, 'tcx> ConstMutationChecker<'a, 'tcx> {
         //
         //     #[const_mutation_allowed]
         //     pub const LOG: Log = Log { msg: "" };
-        match self.tcx.calculate_dtor(def_id, &mut any_dtor) {
+        match self.tcx.calculate_dtor(def_id, &mut |_, _| Ok(())) {
             Some(_) => None,
             None => Some(def_id),
         }