Auto merge of #7977 - Jarcho:multi_needless_borrow, r=xFrednet

Improve `needless_borrow` lint

fixes: #5327
fixes: #1726
fixes: #1212

This is merging `needless_borrow` into the `dereference` pass in preparation for `explicit_auto_deref`. `explicit_auto_deref` needs to implement most of what `needless_borrow` implements in order to work.

There is a minor regression here where `let x: &str = &x.deref()` will trigger `needless_borrow` without triggering `explicit_deref_methods`. Removing the redundant borrow will cause `explicit_deref_methods` to trigger. This will be fixed when `explicit_auto_deref` is implemented.

changelog: Lint `needless_borrow` when a borrow is auto-derefed more than once
changelog: Lint `needless_borrow` in the trailing expression of a block for a match arm

Author: bors

clippy_lints/src/bytecount.rs

@@ -74,10 +74,10 @@ impl<'tcx> LateLintPass<'tcx> for ByteCount {
                     if (p == sym::iter || p == sym!(iter_mut)) && args.len() == 1 {
                         &args[0]
                     } else {
-                        &filter_recv
+                        filter_recv
                     }
                 } else {
-                    &filter_recv
+                    filter_recv
                 };
                 let mut applicability = Applicability::MaybeIncorrect;
                 span_lint_and_sugg(