Remove StableHashProvider.

compiler/rustc_middle/src/ich/hcx.rs

@@ -1,5 +1,4 @@
 use crate::ich;
-use crate::ty::TyCtxt;
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -178,35 +177,6 @@ impl<'a> StableHashingContext<'a> {
     }
 }
 
-/// Something that can provide a stable hashing context.
-pub trait StableHashingContextProvider<'a> {
-    fn get_stable_hashing_context(&self) -> StableHashingContext<'a>;
-}
-
-impl<'a, 'b, T: StableHashingContextProvider<'a>> StableHashingContextProvider<'a> for &'b T {
-    fn get_stable_hashing_context(&self) -> StableHashingContext<'a> {
-        (**self).get_stable_hashing_context()
-    }
-}
-
-impl<'a, 'b, T: StableHashingContextProvider<'a>> StableHashingContextProvider<'a> for &'b mut T {
-    fn get_stable_hashing_context(&self) -> StableHashingContext<'a> {
-        (**self).get_stable_hashing_context()
-    }
-}
-
-impl StableHashingContextProvider<'tcx> for TyCtxt<'tcx> {
-    fn get_stable_hashing_context(&self) -> StableHashingContext<'tcx> {
-        (*self).create_stable_hashing_context()
-    }
-}
-
-impl<'a> StableHashingContextProvider<'a> for StableHashingContext<'a> {
-    fn get_stable_hashing_context(&self) -> StableHashingContext<'a> {
-        self.clone()
-    }
-}
-
 impl<'a> HashStable<StableHashingContext<'a>> for ast::NodeId {
     fn hash_stable(&self, _: &mut StableHashingContext<'a>, _: &mut StableHasher) {
         panic!("Node IDs should not appear in incremental state");

compiler/rustc_middle/src/ich/mod.rs

@@ -1,6 +1,6 @@
 //! ICH - Incremental Compilation Hash
 
-pub use self::hcx::{NodeIdHashingMode, StableHashingContext, StableHashingContextProvider};
+pub use self::hcx::{NodeIdHashingMode, StableHashingContext};
 use rustc_span::symbol::{sym, Symbol};
 
 mod hcx;