From c3b3a861244f5e61d5912ba507e229d978ec1c1c Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Sun, 20 Oct 2019 10:29:11 +1100
Subject: [PATCH] Remove unnecessary `Hash` bounds from various types.

---
 src/bootstrap/cache.rs                                  | 2 +-
 src/librustc/ty/fast_reject.rs                          | 8 ++++----
 src/librustc_data_structures/sharded.rs                 | 2 +-
 src/librustc_data_structures/snapshot_map/mod.rs        | 2 +-
 src/librustc_data_structures/stable_hasher.rs           | 6 +++---
 src/librustc_mir/borrow_check/nll/member_constraints.rs | 4 ++--
 src/libserialize/collection_impls.rs                    | 4 ++--
 7 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/bootstrap/cache.rs b/src/bootstrap/cache.rs
index 53071df855297..4310f2c6fa140 100644
--- a/src/bootstrap/cache.rs
+++ b/src/bootstrap/cache.rs
@@ -161,7 +161,7 @@ impl Ord for Interned<String> {
     }
 }
 
-struct TyIntern<T: Hash + Clone + Eq> {
+struct TyIntern<T: Clone + Eq> {
     items: Vec<T>,
     set: HashMap<T, Interned<T>>,
 }
diff --git a/src/librustc/ty/fast_reject.rs b/src/librustc/ty/fast_reject.rs
index 038b54f1f26dd..27a09b394b8fa 100644
--- a/src/librustc/ty/fast_reject.rs
+++ b/src/librustc/ty/fast_reject.rs
@@ -19,7 +19,7 @@ pub type SimplifiedType = SimplifiedTypeGen<DefId>;
 /// the non-stable but fast to construct DefId-version is the better choice.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
 pub enum SimplifiedTypeGen<D>
-    where D: Copy + Debug + Ord + Eq + Hash
+    where D: Copy + Debug + Ord + Eq
 {
     BoolSimplifiedType,
     CharSimplifiedType,
@@ -123,10 +123,10 @@ pub fn simplify_type(
     }
 }
 
-impl<D: Copy + Debug + Ord + Eq + Hash> SimplifiedTypeGen<D> {
+impl<D: Copy + Debug + Ord + Eq> SimplifiedTypeGen<D> {
     pub fn map_def<U, F>(self, map: F) -> SimplifiedTypeGen<U>
         where F: Fn(D) -> U,
-              U: Copy + Debug + Ord + Eq + Hash,
+              U: Copy + Debug + Ord + Eq,
     {
         match self {
             BoolSimplifiedType => BoolSimplifiedType,
@@ -155,7 +155,7 @@ impl<D: Copy + Debug + Ord + Eq + Hash> SimplifiedTypeGen<D> {
 
 impl<'a, D> HashStable<StableHashingContext<'a>> for SimplifiedTypeGen<D>
 where
-    D: Copy + Debug + Ord + Eq + Hash + HashStable<StableHashingContext<'a>>,
+    D: Copy + Debug + Ord + Eq + HashStable<StableHashingContext<'a>>,
 {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
         mem::discriminant(self).hash_stable(hcx, hasher);
diff --git a/src/librustc_data_structures/sharded.rs b/src/librustc_data_structures/sharded.rs
index d0ff6108d6ea6..2f972eeccdcbd 100644
--- a/src/librustc_data_structures/sharded.rs
+++ b/src/librustc_data_structures/sharded.rs
@@ -90,7 +90,7 @@ impl<T> Sharded<T> {
 
 pub type ShardedHashMap<K, V> = Sharded<FxHashMap<K, V>>;
 
-impl<K: Eq + Hash, V> ShardedHashMap<K, V> {
+impl<K: Eq, V> ShardedHashMap<K, V> {
     pub fn len(&self) -> usize {
         self.lock_shards().iter().map(|shard| shard.len()).sum()
     }
diff --git a/src/librustc_data_structures/snapshot_map/mod.rs b/src/librustc_data_structures/snapshot_map/mod.rs
index ce0aa07cc282c..bdd3dc9665629 100644
--- a/src/librustc_data_structures/snapshot_map/mod.rs
+++ b/src/librustc_data_structures/snapshot_map/mod.rs
@@ -7,7 +7,7 @@ use std::mem;
 mod tests;
 
 pub struct SnapshotMap<K, V>
-    where K: Hash + Clone + Eq
+    where K: Clone + Eq
 {
     map: FxHashMap<K, V>,
     undo_log: Vec<UndoLog<K, V>>,
diff --git a/src/librustc_data_structures/stable_hasher.rs b/src/librustc_data_structures/stable_hasher.rs
index ee4f6a5e785e4..78494401c0baf 100644
--- a/src/librustc_data_structures/stable_hasher.rs
+++ b/src/librustc_data_structures/stable_hasher.rs
@@ -460,7 +460,7 @@ impl_stable_hash_via_hash!(::std::path::Path);
 impl_stable_hash_via_hash!(::std::path::PathBuf);
 
 impl<K, V, R, HCX> HashStable<HCX> for ::std::collections::HashMap<K, V, R>
-    where K: ToStableHashKey<HCX> + Eq + Hash,
+    where K: ToStableHashKey<HCX> + Eq,
           V: HashStable<HCX>,
           R: BuildHasher,
 {
@@ -471,7 +471,7 @@ impl<K, V, R, HCX> HashStable<HCX> for ::std::collections::HashMap<K, V, R>
 }
 
 impl<K, R, HCX> HashStable<HCX> for ::std::collections::HashSet<K, R>
-    where K: ToStableHashKey<HCX> + Eq + Hash,
+    where K: ToStableHashKey<HCX> + Eq,
           R: BuildHasher,
 {
     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
@@ -513,7 +513,7 @@ pub fn hash_stable_hashmap<HCX, K, V, R, SK, F>(
     hasher: &mut StableHasher,
     map: &::std::collections::HashMap<K, V, R>,
     to_stable_hash_key: F)
-    where K: Eq + Hash,
+    where K: Eq,
           V: HashStable<HCX>,
           R: BuildHasher,
           SK: HashStable<HCX> + Ord + Clone,
diff --git a/src/librustc_mir/borrow_check/nll/member_constraints.rs b/src/librustc_mir/borrow_check/nll/member_constraints.rs
index fd195873a55e4..75213d30982f9 100644
--- a/src/librustc_mir/borrow_check/nll/member_constraints.rs
+++ b/src/librustc_mir/borrow_check/nll/member_constraints.rs
@@ -11,7 +11,7 @@ use syntax_pos::Span;
 /// indexed by the region `R0`.
 crate struct MemberConstraintSet<'tcx, R>
 where
-    R: Copy + Hash + Eq,
+    R: Copy + Eq,
 {
     /// Stores the first "member" constraint for a given `R0`. This is an
     /// index into the `constraints` vector below.
@@ -191,7 +191,7 @@ where
 
 impl<'tcx, R> Index<NllMemberConstraintIndex> for MemberConstraintSet<'tcx, R>
 where
-    R: Copy + Hash + Eq,
+    R: Copy + Eq,
 {
     type Output = NllMemberConstraint<'tcx>;
 
diff --git a/src/libserialize/collection_impls.rs b/src/libserialize/collection_impls.rs
index d981740780e6f..f2e9be14c8d12 100644
--- a/src/libserialize/collection_impls.rs
+++ b/src/libserialize/collection_impls.rs
@@ -143,7 +143,7 @@ impl<T> Decodable for BTreeSet<T>
 }
 
 impl<K, V, S> Encodable for HashMap<K, V, S>
-    where K: Encodable + Hash + Eq,
+    where K: Encodable + Eq,
           V: Encodable,
           S: BuildHasher,
 {
@@ -180,7 +180,7 @@ impl<K, V, S> Decodable for HashMap<K, V, S>
 }
 
 impl<T, S> Encodable for HashSet<T, S>
-    where T: Encodable + Hash + Eq,
+    where T: Encodable + Eq,
           S: BuildHasher,
 {
     fn encode<E: Encoder>(&self, s: &mut E) -> Result<(), E::Error> {