style: do not dereference self to perform pattern-matching

Dereferencing `self` as `*self` in order to perform patten-matching
using `ref` is unnecessary and will be done automatically by the
compiler (match ergonomics, introduced in Rust 1.26).

lib/src/backend.rs

@@ -230,25 +230,25 @@ pub enum TreeValue {
 impl ContentHash for TreeValue {
     fn hash(&self, state: &mut impl digest::Update) {
         use TreeValue::*;
-        match *self {
-            File { ref id, executable } => {
+        match self {
+            File { id, executable } => {
                 state.update(&0u32.to_le_bytes());
                 id.hash(state);
                 executable.hash(state);
             }
-            Symlink(ref id) => {
+            Symlink(id) => {
                 state.update(&1u32.to_le_bytes());
                 id.hash(state);
             }
-            Tree(ref id) => {
+            Tree(id) => {
                 state.update(&2u32.to_le_bytes());
                 id.hash(state);
             }
-            GitSubmodule(ref id) => {
+            GitSubmodule(id) => {
                 state.update(&3u32.to_le_bytes());
                 id.hash(state);
             }
-            Conflict(ref id) => {
+            Conflict(id) => {
                 state.update(&4u32.to_le_bytes());
                 id.hash(state);
             }

lib/src/content_hash.rs

@@ -71,9 +71,9 @@ impl ContentHash for String {
 
 impl<T: ContentHash> ContentHash for Option<T> {
     fn hash(&self, state: &mut impl digest::Update) {
-        match *self {
+        match self {
             None => state.update(&[0]),
-            Some(ref x) => {
+            Some(x) => {
                 state.update(&[1]);
                 x.hash(state)
             }

lib/src/op_store.rs

@@ -125,15 +125,12 @@ pub enum RefTarget {
 impl ContentHash for RefTarget {
     fn hash(&self, state: &mut impl digest::Update) {
         use RefTarget::*;
-        match *self {
-            Normal(ref id) => {
+        match self {
+            Normal(id) => {
                 state.update(&0u32.to_le_bytes());
                 id.hash(state);
             }
-            Conflict {
-                ref removes,
-                ref adds,
-            } => {
+            Conflict { removes, adds } => {
                 state.update(&1u32.to_le_bytes());
                 removes.hash(state);
                 adds.hash(state);

lib/src/simple_op_store_model.rs

@@ -181,13 +181,13 @@ impl TSerializable for RefTarget {
   fn write_to_out_protocol(&self, o_prot: &mut dyn TOutputProtocol) -> thrift::Result<()> {
     let struct_ident = TStructIdentifier::new("RefTarget");
     o_prot.write_struct_begin(&struct_ident)?;
-    match *self {
-      RefTarget::CommitId(ref f) => {
+    match self {
+      RefTarget::CommitId(f) => {
         o_prot.write_field_begin(&TFieldIdentifier::new("commit_id", TType::String, 1))?;
         o_prot.write_bytes(f)?;
         o_prot.write_field_end()?;
       },
-      RefTarget::Conflict(ref f) => {
+      RefTarget::Conflict(f) => {
         o_prot.write_field_begin(&TFieldIdentifier::new("conflict", TType::Struct, 2))?;
         f.write_to_out_protocol(o_prot)?;
         o_prot.write_field_end()?;