Move HashStable bound to the trait definition.

Author: cjgillot

src/librustc/ty/query/config.rs

@@ -10,6 +10,7 @@ use rustc_hir::def_id::DefId;
 
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::stable_hasher::HashStable;
 use rustc_query_system::dep_graph::{DepContext, DepNode};
 use rustc_session::Session;
 use std::borrow::Cow;
@@ -25,7 +26,7 @@ pub trait QueryConfig<CTX> {
 }
 
 pub trait QueryContext: DepContext {
-    type Query: Clone;
+    type Query: Clone + HashStable<Self::StableHashingContext>;
 
     /// Access the session.
     fn session(&self) -> &Session;

src/librustc/ty/query/job.rs

@@ -405,7 +405,6 @@ fn connected_to_root<CTX: QueryContext>(
 fn pick_query<'a, CTX, T, F>(query_map: &QueryMap<CTX>, tcx: CTX, queries: &'a [T], f: F) -> &'a T
 where
     CTX: QueryContext,
-    CTX::Query: HashStable<CTX::StableHashingContext>,
     F: Fn(&T) -> (Span, QueryJobId<CTX::DepKind>),
 {
     // Deterministically pick an entry point
@@ -437,10 +436,7 @@ fn remove_cycle<CTX: QueryContext>(
     jobs: &mut Vec<QueryJobId<CTX::DepKind>>,
     wakelist: &mut Vec<Lrc<QueryWaiter<CTX>>>,
     tcx: CTX,
-) -> bool
-where
-    CTX::Query: HashStable<CTX::StableHashingContext>,
-{
+) -> bool {
     let mut visited = FxHashSet::default();
     let mut stack = Vec::new();
     // Look for a cycle starting with the last query in `jobs`
@@ -564,10 +560,7 @@ pub unsafe fn handle_deadlock() {
 /// There may be multiple cycles involved in a deadlock, so this searches
 /// all active queries for cycles before finally resuming all the waiters at once.
 #[cfg(parallel_compiler)]
-fn deadlock<CTX: QueryContext>(tcx: CTX, registry: &rayon_core::Registry)
-where
-    CTX::Query: HashStable<CTX::StableHashingContext>,
-{
+fn deadlock<CTX: QueryContext>(tcx: CTX, registry: &rayon_core::Registry) {
     let on_panic = OnDrop(|| {
         eprintln!("deadlock handler panicked, aborting process");
         process::abort();