Rollup merge of #56452 - sinkuu:redundant_clone, r=nikic

Remove redundant clones

Author: pietroalbini

src/librustc_mir/monomorphize/partitioning.rs

@@ -585,7 +585,7 @@ fn merge_codegen_units<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>,
  // smallest into each other) we're sure to start off with a deterministic
  // order (sorted by name). This'll mean that if two cgus have the same size
  // the stable sort below will keep everything nice and deterministic.
- codegen_units.sort_by_key(|cgu| cgu.name().clone());
+ codegen_units.sort_by_key(|cgu| *cgu.name());
 
  // Merge the two smallest codegen units until the target size is reached.
  while codegen_units.len() > target_cgu_count {
@@ -985,7 +985,7 @@ fn collect_and_partition_mono_items<'a, 'tcx>(
  output.push_str(" @@");
  let mut empty = Vec::new();
  let cgus = item_to_cgus.get_mut(i).unwrap_or(&mut empty);
- cgus.as_mut_slice().sort_by_cached_key(|&(ref name, _)| name.clone());
+ cgus.sort_by_key(|(name, _)| *name);
  cgus.dedup();
  for &(ref cgu_name, (linkage, _)) in cgus.iter() {
  output.push_str(" ");

src/librustc_resolve/build_reduced_graph.rs

@@ -318,7 +318,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
  // This particular use tree
  &tree, id, &prefix, true,
  // The whole `use` item
- parent_scope.clone(), item, ty::Visibility::Invisible, root_span,
+ parent_scope, item, ty::Visibility::Invisible, root_span,
  );
  }
  }

src/libsyntax/ext/tt/macro_parser.rs

@@ -309,7 +309,7 @@ fn create_matches(len: usize) -> Box<[Rc<NamedMatchVec>]> {
  vec![]
  } else {
  let empty_matches = Rc::new(SmallVec::new());
- vec![empty_matches.clone(); len]
+ vec![empty_matches; len]
  }.into_boxed_slice()
 }