compiler: use `copied` instead of manual `map`

compiler/rustc_ast_lowering/src/expr.rs

@@ -41,8 +41,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     }
                     // Merge attributes into the inner expression.
                     if !e.attrs.is_empty() {
-                        let old_attrs =
-                            self.attrs.get(&ex.hir_id.local_id).map(|la| *la).unwrap_or(&[]);
+                        let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
                         self.attrs.insert(
                             ex.hir_id.local_id,
                             &*self.arena.alloc_from_iter(

compiler/rustc_ast_lowering/src/lib.rs

@@ -505,7 +505,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     /// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name
     /// resolver (if any).
     fn orig_opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
-        self.resolver.node_id_to_def_id.get(&node).map(|local_def_id| *local_def_id)
+        self.resolver.node_id_to_def_id.get(&node).copied()
     }
 
     /// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name
@@ -548,7 +548,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.generics_def_id_map
             .iter()
             .rev()
-            .find_map(|map| map.get(&local_def_id).map(|local_def_id| *local_def_id))
+            .find_map(|map| map.get(&local_def_id).copied())
             .unwrap_or(local_def_id)
     }
 

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -860,7 +860,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                         self.suggest_boxing_for_return_impl_trait(
                             err,
                             ret_sp,
-                            prior_arms.iter().chain(std::iter::once(&arm_span)).map(|s| *s),
+                            prior_arms.iter().chain(std::iter::once(&arm_span)).copied(),
                         );
                     }
                 }

compiler/rustc_lint/src/context.rs

@@ -715,7 +715,7 @@ pub trait LintContext: Sized {
                     db.note("see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information");
                 },
                 BuiltinLintDiagnostics::UnexpectedCfgName((name, name_span), value) => {
-                    let possibilities: Vec<Symbol> = sess.parse_sess.check_config.expecteds.keys().map(|s| *s).collect();
+                    let possibilities: Vec<Symbol> = sess.parse_sess.check_config.expecteds.keys().copied().collect();
 
                     // Suggest the most probable if we found one
                     if let Some(best_match) = find_best_match_for_name(&possibilities, name, None) {

compiler/rustc_middle/src/mir/pretty.rs

@@ -1337,7 +1337,7 @@ pub fn write_allocations<'tcx>(
     fn alloc_ids_from_alloc(
         alloc: ConstAllocation<'_>,
     ) -> impl DoubleEndedIterator<Item = AllocId> + '_ {
-        alloc.inner().provenance().ptrs().values().map(|id| *id)
+        alloc.inner().provenance().ptrs().values().copied()
     }
 
     fn alloc_ids_from_const_val(val: ConstValue<'_>) -> impl Iterator<Item = AllocId> + '_ {

compiler/rustc_ty_utils/src/assoc.rs

@@ -43,7 +43,7 @@ fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &[DefId] {
                                     trait_fn_def_id,
                                 )
                             })
-                            .map(|def_id| *def_id),
+                            .copied(),
                     ),
             )
         }
@@ -69,7 +69,7 @@ fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &[DefId] {
                                     impl_fn_def_id,
                                 )
                             })
-                            .map(|def_id| *def_id)
+                            .copied()
                     })),
             )
         }