Use more impl header lifetime elision

There are two big categories of changes in here

- Removing lifetimes from common traits that can essentially never user a lifetime from an input (particularly `Drop` & `Debug`)
- Forwarding impls that are only possible because the lifetime doesn't matter (like `impl<R: Read + ?Sized> Read for &mut R`)

I omitted things that seemed like they could be more controversial, like the handful of iterators that have a `Item: 'static` despite the iterator having a lifetime or the `PartialEq` implementations where the flipped one cannot elide the lifetime.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libstd/sync/mpsc/select.rs b/src/libstd/sync/mpsc/select.rs
index 8f41680a818..4c629fa2e4c 100644
--- a/src/libstd/sync/mpsc/select.rs
+++ b/src/libstd/sync/mpsc/select.rs
@@ -321,7 +321,7 @@ impl Drop for Select {
     }
 }
 
-impl<'rx, T: Send> Drop for Handle<'rx, T> {
+impl<T: Send> Drop for Handle<'_, T> {
     fn drop(&mut self) {
         unsafe { self.remove() }
     }
@@ -347,7 +347,7 @@ impl fmt::Debug for Select {
     }
 }
 
-impl<'rx, T:Send+'rx> fmt::Debug for Handle<'rx, T> {
+impl<T: Send> fmt::Debug for Handle<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("Handle").finish()
     }