style: remove redundant ref keywords

See
<https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
for more details.

Author: rami3l

src/diskio/immediate.rs

@@ -69,8 +69,8 @@ impl Executor for ImmediateUnpacker {
     fn dispatch(&self, mut item: Item) -> Box<dyn Iterator<Item = CompletedIo> + '_> {
         item.result = match &mut item.kind {
             super::Kind::Directory => super::create_dir(&item.full_path),
-            super::Kind::File(ref contents) => {
-                if let super::FileBuffer::Immediate(ref contents) = &contents {
+            super::Kind::File(contents) => {
+                if let super::FileBuffer::Immediate(contents) = &contents {
                     super::write_file(&item.full_path, contents, item.mode)
                 } else {
                     unreachable!()

src/diskio/mod.rs

@@ -81,14 +81,14 @@ pub(crate) enum FileBuffer {
 impl FileBuffer {
     /// All the buffers space to be re-used when the last reference to it is dropped.
     pub(crate) fn clear(&mut self) {
-        if let FileBuffer::Threaded(ref mut contents) = self {
+        if let FileBuffer::Threaded(contents) = self {
             contents.clear()
         }
     }
 
     pub(crate) fn len(&self) -> usize {
         match self {
-            FileBuffer::Immediate(ref vec) => vec.len(),
+            FileBuffer::Immediate(vec) => vec.len(),
             FileBuffer::Threaded(PoolReference::Owned(owned, _)) => owned.len(),
             FileBuffer::Threaded(PoolReference::Mut(mutable, _)) => mutable.len(),
         }
@@ -109,7 +109,7 @@ impl Deref for FileBuffer {
 
     fn deref(&self) -> &Self::Target {
         match self {
-            FileBuffer::Immediate(ref vec) => vec,
+            FileBuffer::Immediate(vec) => vec,
             FileBuffer::Threaded(PoolReference::Owned(owned, _)) => owned,
             FileBuffer::Threaded(PoolReference::Mut(mutable, _)) => mutable,
         }
@@ -119,7 +119,7 @@ impl Deref for FileBuffer {
 impl DerefMut for FileBuffer {
     fn deref_mut(&mut self) -> &mut Self::Target {
         match self {
-            FileBuffer::Immediate(ref mut vec) => vec,
+            FileBuffer::Immediate(vec) => vec,
             FileBuffer::Threaded(PoolReference::Owned(_, _)) => {
                 unimplemented!()
             }
@@ -337,15 +337,11 @@ pub(crate) fn perform<F: Fn(usize)>(item: &mut Item, chunk_complete_callback: F)
     // Files, write them.
     item.result = match &mut item.kind {
         Kind::Directory => create_dir(&item.full_path),
-        Kind::File(ref mut contents) => {
+        Kind::File(contents) => {
             contents.clear();
             match contents {
-                FileBuffer::Immediate(ref contents) => {
-                    write_file(&item.full_path, contents, item.mode)
-                }
-                FileBuffer::Threaded(ref mut contents) => {
-                    write_file(&item.full_path, contents, item.mode)
-                }
+                FileBuffer::Immediate(contents) => write_file(&item.full_path, contents, item.mode),
+                FileBuffer::Threaded(contents) => write_file(&item.full_path, contents, item.mode),
             }
         }
         Kind::IncrementalFile(incremental_file) => write_file_incremental(

src/toolchain.rs

@@ -87,11 +87,11 @@ impl<'a> Toolchain<'a> {
             ActiveReason::CommandLine => {
                 "the +toolchain on the command line specifies an uninstalled toolchain".to_string()
             }
-            ActiveReason::OverrideDB(ref path) => format!(
+            ActiveReason::OverrideDB(path) => format!(
                 "the directory override for '{}' specifies an uninstalled toolchain",
                 utils::canonicalize_path(path, cfg.notify_handler.as_ref()).display(),
             ),
-            ActiveReason::ToolchainFile(ref path) => format!(
+            ActiveReason::ToolchainFile(path) => format!(
                 "the toolchain file at '{}' specifies an uninstalled toolchain",
                 utils::canonicalize_path(path, cfg.notify_handler.as_ref()).display(),
             ),