Fix `clippy::needless_borrow` in the compiler

`x clippy compiler -Aclippy::all -Wclippy::needless_borrow --fix`.

Then I had to remove a few unnecessary parens and muts that were exposed
now.

5 files changed, 13 insertions, 13 deletions

diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
index 1b160eca92d..3f30b3f2b4c 100644
--- a/compiler/rustc_incremental/src/assert_dep_graph.rs
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -231,13 +231,13 @@ fn dump_graph(query: &DepGraphQuery) {
             // Expect one of: "-> target", "source -> target", or "source ->".
             let edge_filter =
                 EdgeFilter::new(&string).unwrap_or_else(|e| bug!("invalid filter: {}", e));
-            let sources = node_set(&query, &edge_filter.source);
-            let targets = node_set(&query, &edge_filter.target);
-            filter_nodes(&query, &sources, &targets)
+            let sources = node_set(query, &edge_filter.source);
+            let targets = node_set(query, &edge_filter.target);
+            filter_nodes(query, &sources, &targets)
         }
         Err(_) => query.nodes().into_iter().map(|n| n.kind).collect(),
     };
-    let edges = filter_edges(&query, &nodes);
+    let edges = filter_edges(query, &nodes);
 
     {
         // dump a .txt file with just the edges:
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index 5dd06c6ca4f..eaf83b7ee5f 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -378,15 +378,15 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
             };
             self.checked_attrs.insert(attr.id);
             for label in assertion.clean.items().into_sorted_stable_ord() {
-                let dep_node = DepNode::from_label_string(self.tcx, &label, def_path_hash).unwrap();
+                let dep_node = DepNode::from_label_string(self.tcx, label, def_path_hash).unwrap();
                 self.assert_clean(item_span, dep_node);
             }
             for label in assertion.dirty.items().into_sorted_stable_ord() {
-                let dep_node = DepNode::from_label_string(self.tcx, &label, def_path_hash).unwrap();
+                let dep_node = DepNode::from_label_string(self.tcx, label, def_path_hash).unwrap();
                 self.assert_dirty(item_span, dep_node);
             }
             for label in assertion.loaded_from_disk.items().into_sorted_stable_ord() {
-                let dep_node = DepNode::from_label_string(self.tcx, &label, def_path_hash).unwrap();
+                let dep_node = DepNode::from_label_string(self.tcx, label, def_path_hash).unwrap();
                 self.assert_loaded_from_disk(item_span, dep_node);
             }
         }
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index f56fb0d0534..2d809030e58 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -499,7 +499,7 @@ fn lock_directory(
 }
 
 fn delete_session_dir_lock_file(sess: &Session, lock_file_path: &Path) {
-    if let Err(err) = safe_remove_file(&lock_file_path) {
+    if let Err(err) = safe_remove_file(lock_file_path) {
         sess.emit_warning(errors::DeleteLock { path: lock_file_path, err });
     }
 }
@@ -847,10 +847,10 @@ pub(crate) fn garbage_collect_session_directories(sess: &Session) -> io::Result<
 fn delete_old(sess: &Session, path: &Path) {
     debug!("garbage_collect_session_directories() - deleting `{}`", path.display());
 
-    if let Err(err) = safe_remove_dir_all(&path) {
-        sess.emit_warning(errors::SessionGcFailed { path: &path, err });
+    if let Err(err) = safe_remove_dir_all(path) {
+        sess.emit_warning(errors::SessionGcFailed { path: path, err });
     } else {
-        delete_session_dir_lock_file(sess, &lock_file_path(&path));
+        delete_session_dir_lock_file(sess, &lock_file_path(path));
     }
 }
 
diff --git a/compiler/rustc_incremental/src/persist/load.rs b/compiler/rustc_incremental/src/persist/load.rs
index 6dfc4096910..f2c1d0b83aa 100644
--- a/compiler/rustc_incremental/src/persist/load.rs
+++ b/compiler/rustc_incremental/src/persist/load.rs
@@ -99,7 +99,7 @@ fn load_dep_graph(sess: &Session) -> LoadResult<(SerializedDepGraph, WorkProduct
 
     // Calling `sess.incr_comp_session_dir()` will panic if `sess.opts.incremental.is_none()`.
     // Fortunately, we just checked that this isn't the case.
-    let path = dep_graph_path(&sess);
+    let path = dep_graph_path(sess);
     let expected_hash = sess.opts.dep_tracking_hash(false);
 
     let mut prev_work_products = UnordMap::default();
diff --git a/compiler/rustc_incremental/src/persist/work_product.rs b/compiler/rustc_incremental/src/persist/work_product.rs
index fb96bed5a71..1ee3d13922b 100644
--- a/compiler/rustc_incremental/src/persist/work_product.rs
+++ b/compiler/rustc_incremental/src/persist/work_product.rs
@@ -31,7 +31,7 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
             }
             Err(err) => {
                 sess.emit_warning(errors::CopyWorkProductToCache {
-                    from: &path,
+                    from: path,
                     to: &path_in_incr_dir,
                     err,
                 });