Replace map(|x| (*x).clone()) with cloned().

This resolves #22243, at least for one-letter variable names.

Author: ruuda

src/libcollections/dlist.rs

@@ -1013,7 +1013,7 @@ mod tests {
 
     #[cfg(test)]
     fn list_from<T: Clone>(v: &[T]) -> DList<T> {
-        v.iter().map(|x| (*x).clone()).collect()
+        v.iter().cloned().collect()
     }
 
     #[test]

src/librustc/middle/resolve_lifetime.rs

@@ -562,7 +562,7 @@ pub fn early_bound_lifetimes<'a>(generics: &'a ast::Generics) -> Vec<ast::Lifeti
 
     generics.lifetimes.iter()
         .filter(|l| referenced_idents.iter().any(|&i| i == l.lifetime.name))
-        .map(|l| (*l).clone())
+        .cloned()
         .collect()
 }
 

src/librustc/middle/traits/select.rs

@@ -738,7 +738,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     {
         let cache = self.pick_candidate_cache();
         let hashmap = cache.hashmap.borrow();
-        hashmap.get(&cache_fresh_trait_pred.0.trait_ref).map(|c| (*c).clone())
+        hashmap.get(&cache_fresh_trait_pred.0.trait_ref).cloned()
     }
 
     fn insert_candidate_cache(&mut self,

src/librustc_trans/trans/expr.rs

@@ -1153,7 +1153,7 @@ fn trans_rvalue_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
                 let trait_ref =
                     bcx.tcx().object_cast_map.borrow()
                                              .get(&expr.id)
-                                             .map(|t| (*t).clone())
+                                             .cloned()
                                              .unwrap();
                 let trait_ref = bcx.monomorphize(&trait_ref);
                 let datum = unpack_datum!(bcx, trans(bcx, &**val));

src/librustc_trans/trans/type_of.rs

@@ -67,7 +67,7 @@ pub fn untuple_arguments_if_necessary<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                                                 abi: abi::Abi)
                                                 -> Vec<Ty<'tcx>> {
     if abi != abi::RustCall {
-        return inputs.iter().map(|x| (*x).clone()).collect()
+        return inputs.iter().cloned().collect()
     }
 
     if inputs.len() == 0 {

src/librustdoc/visit_ast.rs

@@ -333,7 +333,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                     name: name,
                     items: items.clone(),
                     generics: gen.clone(),
-                    bounds: b.iter().map(|x| (*x).clone()).collect(),
+                    bounds: b.iter().cloned().collect(),
                     id: item.id,
                     attrs: item.attrs.clone(),
                     whence: item.span,

src/libsyntax/ext/deriving/generic/mod.rs

@@ -410,7 +410,7 @@ impl<'a> TraitDef<'a> {
         let mut ty_params = ty_params.into_vec();
 
         // Copy the lifetimes
-        lifetimes.extend(generics.lifetimes.iter().map(|l| (*l).clone()));
+        lifetimes.extend(generics.lifetimes.iter().cloned());
 
         // Create the type parameters.
         ty_params.extend(generics.ty_params.iter().map(|ty_param| {

src/libsyntax/ext/tt/macro_parser.rs

@@ -282,9 +282,7 @@ pub fn parse(sess: &ParseSess,
              ms: &[TokenTree])
              -> ParseResult {
     let mut cur_eis = Vec::new();
-    cur_eis.push(initial_matcher_pos(Rc::new(ms.iter()
-                                                .map(|x| (*x).clone())
-                                                .collect()),
+    cur_eis.push(initial_matcher_pos(Rc::new(ms.iter().cloned().collect()),
                                      None,
                                      rdr.peek().sp.lo));
 

src/libsyntax/ext/tt/macro_rules.rs

@@ -160,7 +160,7 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
                                                       None,
                                                       None,
                                                       arg.iter()
-                                                         .map(|x| (*x).clone())
+                                                         .cloned()
                                                          .collect(),
                                                       true);
             match parse(cx.parse_sess(), cx.cfg(), arg_rdr, lhs_tt) {

src/libsyntax/parse/lexer/comments.rs

@@ -82,7 +82,7 @@ pub fn strip_doc_comment_decoration(comment: &str) -> String {
         while j > i && lines[j - 1].trim().is_empty() {
             j -= 1;
         }
-        return lines[i..j].iter().map(|x| (*x).clone()).collect();
+        return lines[i..j].iter().cloned().collect();
     }
 
     /// remove a "[ \t]*\*" block from each line, if possible