remove some manual hash stable impls

compiler/rustc_data_structures/src/stable_hasher.rs

@@ -3,6 +3,7 @@ use rustc_index::bit_set;
 use rustc_index::vec;
 use smallvec::SmallVec;
 use std::hash::{BuildHasher, Hash, Hasher};
+use std::marker::PhantomData;
 use std::mem;
 
 #[cfg(test)]
@@ -261,6 +262,10 @@ impl<CTX> HashStable<CTX> for ! {
     }
 }
 
+impl<CTX, T> HashStable<CTX> for PhantomData<T> {
+    fn hash_stable(&self, _ctx: &mut CTX, _hasher: &mut StableHasher) {}
+}
+
 impl<CTX> HashStable<CTX> for ::std::num::NonZeroU32 {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {

compiler/rustc_middle/src/traits/query.rs

@@ -9,13 +9,9 @@ use crate::infer::canonical::{Canonical, QueryResponse};
 use crate::ty::error::TypeError;
 use crate::ty::subst::GenericArg;
 use crate::ty::{self, Ty, TyCtxt};
-
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_errors::struct_span_err;
-use rustc_query_system::ich::StableHashingContext;
 use rustc_span::source_map::Span;
 use std::iter::FromIterator;
-use std::mem;
 
 pub mod type_op {
     use crate::ty::fold::TypeFoldable;
@@ -226,29 +222,9 @@ pub struct NormalizationResult<'tcx> {
 /// case they are called implied bounds). They are fed to the
 /// `OutlivesEnv` which in turn is supplied to the region checker and
 /// other parts of the inference system.
-#[derive(Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, TypeFoldable, TypeVisitable, Lift, HashStable)]
 pub enum OutlivesBound<'tcx> {
     RegionSubRegion(ty::Region<'tcx>, ty::Region<'tcx>),
     RegionSubParam(ty::Region<'tcx>, ty::ParamTy),
     RegionSubProjection(ty::Region<'tcx>, ty::ProjectionTy<'tcx>),
 }
-
-impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for OutlivesBound<'tcx> {
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        mem::discriminant(self).hash_stable(hcx, hasher);
-        match *self {
-            OutlivesBound::RegionSubRegion(ref a, ref b) => {
-                a.hash_stable(hcx, hasher);
-                b.hash_stable(hcx, hasher);
-            }
-            OutlivesBound::RegionSubParam(ref a, ref b) => {
-                a.hash_stable(hcx, hasher);
-                b.hash_stable(hcx, hasher);
-            }
-            OutlivesBound::RegionSubProjection(ref a, ref b) => {
-                a.hash_stable(hcx, hasher);
-                b.hash_stable(hcx, hasher);
-            }
-        }
-    }
-}

compiler/rustc_middle/src/ty/impls_ty.rs

@@ -101,46 +101,6 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::subst::GenericArgKin
     }
 }
 
-impl<'a> HashStable<StableHashingContext<'a>> for ty::EarlyBoundRegion {
-    #[inline]
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        self.def_id.hash_stable(hcx, hasher);
-        self.index.hash_stable(hcx, hasher);
-        self.name.hash_stable(hcx, hasher);
-    }
-}
-
-impl<'a> HashStable<StableHashingContext<'a>> for ty::RegionVid {
-    #[inline]
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        self.index().hash_stable(hcx, hasher);
-    }
-}
-
-impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::ConstVid<'tcx> {
-    #[inline]
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        self.index.hash_stable(hcx, hasher);
-    }
-}
-
-impl<'tcx> HashStable<StableHashingContext<'tcx>> for ty::BoundVar {
-    #[inline]
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'tcx>, hasher: &mut StableHasher) {
-        self.index().hash_stable(hcx, hasher);
-    }
-}
-
-impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ty::Binder<'tcx, T>
-where
-    T: HashStable<StableHashingContext<'a>>,
-{
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        self.as_ref().skip_binder().hash_stable(hcx, hasher);
-        self.bound_vars().hash_stable(hcx, hasher);
-    }
-}
-
 // AllocIds get resolved to whatever they point to (to be stable)
 impl<'a> HashStable<StableHashingContext<'a>> for mir::interpret::AllocId {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {

compiler/rustc_middle/src/ty/mod.rs

@@ -1182,22 +1182,13 @@ impl<'tcx> OpaqueHiddenType<'tcx> {
 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
 /// regions/types/consts within the same universe simply have an unknown relationship to one
 /// another.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(HashStable, TyEncodable, TyDecodable)]
 pub struct Placeholder<T> {
     pub universe: UniverseIndex,
     pub name: T,
 }
 
-impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
-where
-    T: HashStable<StableHashingContext<'a>>,
-{
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        self.universe.hash_stable(hcx, hasher);
-        self.name.hash_stable(hcx, hasher);
-    }
-}
-
 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
 
 pub type PlaceholderType = Placeholder<BoundVar>;
@@ -1581,6 +1572,7 @@ impl<'tcx> PolyTraitRef<'tcx> {
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
+#[derive(HashStable)]
 pub struct ParamEnvAnd<'tcx, T> {
     pub param_env: ParamEnv<'tcx>,
     pub value: T,
@@ -1598,18 +1590,6 @@ impl<'tcx, T> ParamEnvAnd<'tcx, T> {
     }
 }
 
-impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
-where
-    T: HashStable<StableHashingContext<'a>>,
-{
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        let ParamEnvAnd { ref param_env, ref value } = *self;
-
-        param_env.hash_stable(hcx, hasher);
-        value.hash_stable(hcx, hasher);
-    }
-}
-
 #[derive(Copy, Clone, Debug, HashStable, Encodable, Decodable)]
 pub struct Destructor {
     /// The `DefId` of the destructor method

compiler/rustc_middle/src/ty/sty.rs

@@ -986,6 +986,7 @@ pub enum BoundVariableKind {
 ///
 /// `Decodable` and `Encodable` are implemented for `Binder<T>` using the `impl_binder_encode_decode!` macro.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(HashStable)]
 pub struct Binder<'tcx, T>(T, &'tcx List<BoundVariableKind>);
 
 impl<'tcx, T> Binder<'tcx, T>
@@ -1332,6 +1333,7 @@ impl<'tcx> fmt::Debug for Region<'tcx> {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, PartialOrd, Ord)]
+#[derive(HashStable)]
 pub struct EarlyBoundRegion {
     pub def_id: DefId,
     pub index: u32,
@@ -1345,14 +1347,16 @@ impl fmt::Debug for EarlyBoundRegion {
 }
 
 /// A **`const`** **v**ariable **ID**.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(HashStable, TyEncodable, TyDecodable)]
 pub struct ConstVid<'tcx> {
     pub index: u32,
     pub phantom: PhantomData<&'tcx ()>,
 }
 
 rustc_index::newtype_index! {
     /// A **region** (lifetime) **v**ariable **ID**.
+    #[derive(HashStable)]
     pub struct RegionVid {
         DEBUG_FORMAT = custom,
     }
@@ -1365,6 +1369,7 @@ impl Atom for RegionVid {
 }
 
 rustc_index::newtype_index! {
+    #[derive(HashStable)]
     pub struct BoundVar { .. }
 }