Fix clippy::clone_on_copy warnings

Author: mati865

src/liballoc/collections/linked_list.rs

@@ -237,15 +237,15 @@ impl<T> LinkedList<T> {
 
         // Not creating new mutable (unique!) references overlapping `element`.
         match node.prev {
-            Some(prev) => (*prev.as_ptr()).next = node.next.clone(),
+            Some(prev) => (*prev.as_ptr()).next = node.next,
             // this node is the head node
-            None => self.head = node.next.clone(),
+            None => self.head = node.next,
         };
 
         match node.next {
-            Some(next) => (*next.as_ptr()).prev = node.prev.clone(),
+            Some(next) => (*next.as_ptr()).prev = node.prev,
             // this node is the tail node
-            None => self.tail = node.prev.clone(),
+            None => self.tail = node.prev,
         };
 
         self.len -= 1;

src/liballoc/rc.rs

@@ -815,7 +815,7 @@ impl<T> Rc<[T]> {
                     let slice = from_raw_parts_mut(self.elems, self.n_elems);
                     ptr::drop_in_place(slice);
 
-                    Global.dealloc(self.mem, self.layout.clone());
+                    Global.dealloc(self.mem, self.layout);
                 }
             }
         }

src/liballoc/sync.rs

@@ -703,7 +703,7 @@ impl<T> Arc<[T]> {
                     let slice = from_raw_parts_mut(self.elems, self.n_elems);
                     ptr::drop_in_place(slice);
 
-                    Global.dealloc(self.mem.cast(), self.layout.clone());
+                    Global.dealloc(self.mem.cast(), self.layout);
                 }
             }
         }

src/libcore/alloc.rs

@@ -827,11 +827,11 @@ pub unsafe trait Alloc {
         let old_size = layout.size();
 
         if new_size >= old_size {
-            if let Ok(()) = self.grow_in_place(ptr, layout.clone(), new_size) {
+            if let Ok(()) = self.grow_in_place(ptr, layout, new_size) {
                 return Ok(ptr);
             }
         } else if new_size < old_size {
-            if let Ok(()) = self.shrink_in_place(ptr, layout.clone(), new_size) {
+            if let Ok(()) = self.shrink_in_place(ptr, layout, new_size) {
                 return Ok(ptr);
             }
         }

src/libstd/sys/unix/alloc.rs

@@ -29,7 +29,7 @@ unsafe impl GlobalAlloc for System {
         if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
             libc::calloc(layout.size(), 1) as *mut u8
         } else {
-            let ptr = self.alloc(layout.clone());
+            let ptr = self.alloc(layout);
             if !ptr.is_null() {
                 ptr::write_bytes(ptr, 0, layout.size());
             }