Eliminate some 'a lifetimes.

Putting `+ 'tcx` on the `QueryDispatcher` trait lets a few other places
be simplified.

Author: nnethercote

compiler/rustc_query_impl/src/lib.rs

@@ -86,10 +86,7 @@ where
     }
 
     #[inline(always)]
-    fn query_state<'a>(self, qcx: QueryCtxt<'tcx>) -> &'a QueryState<'tcx, Self::Key>
-    where
-        QueryCtxt<'tcx>: 'a,
-    {
+    fn query_state(self, qcx: QueryCtxt<'tcx>) -> &'tcx QueryState<'tcx, Self::Key> {
         // Safety:
         // This is just manually doing the subfield referencing through pointer math.
         unsafe {
@@ -100,7 +97,7 @@ where
     }
 
     #[inline(always)]
-    fn query_cache<'a>(self, qcx: QueryCtxt<'tcx>) -> &'a Self::Cache {
+    fn query_cache(self, qcx: QueryCtxt<'tcx>) -> &'tcx Self::Cache {
         // Safety:
         // This is just manually doing the subfield referencing through pointer math.
         unsafe {
@@ -216,12 +213,12 @@ trait QueryDispatcherUnerased<'tcx> {
     ) -> Self::UnerasedValue;
 }
 
-pub fn query_system<'a>(
+pub fn query_system<'tcx>(
     local_providers: Providers,
     extern_providers: ExternProviders,
     on_disk_cache: Option<OnDiskCache>,
     incremental: bool,
-) -> QuerySystem<'a> {
+) -> QuerySystem<'tcx> {
     QuerySystem {
         states: Default::default(),
         arenas: Default::default(),

compiler/rustc_query_system/src/query/dispatcher.rs

@@ -25,7 +25,7 @@ type DepContextOf<'tcx, This: QueryDispatcher<'tcx>> =
 /// Those types are not visible from this `rustc_query_system` crate.
 ///
 /// "Dispatcher" should be understood as a near-synonym of "vtable".
-pub trait QueryDispatcher<'tcx>: Copy {
+pub trait QueryDispatcher<'tcx>: Copy + 'tcx {
     fn name(self) -> &'static str;
 
     /// Query context used by this dispatcher, i.e. `rustc_query_impl::QueryCtxt`.
@@ -41,10 +41,10 @@ pub trait QueryDispatcher<'tcx>: Copy {
     fn format_value(self) -> fn(&Self::Value) -> String;
 
     // Don't use this method to access query results, instead use the methods on TyCtxt
-    fn query_state<'a>(self, tcx: Self::Qcx) -> &'a QueryState<'tcx, Self::Key>;
+    fn query_state(self, tcx: Self::Qcx) -> &'tcx QueryState<'tcx, Self::Key>;
 
     // Don't use this method to access query results, instead use the methods on TyCtxt
-    fn query_cache<'a>(self, tcx: Self::Qcx) -> &'a Self::Cache;
+    fn query_cache(self, tcx: Self::Qcx) -> &'tcx Self::Cache;
 
     fn will_cache_on_disk_for_key(self, tcx: DepContextOf<'tcx, Self>, key: &Self::Key) -> bool;
 

compiler/rustc_query_system/src/query/plumbing.rs

@@ -127,11 +127,11 @@ impl<'tcx, K> Default for QueryState<'tcx, K> {
 
 /// A type representing the responsibility to execute the job in the `job` field.
 /// This will poison the relevant query if dropped.
-struct JobOwner<'a, 'tcx, K>
+struct JobOwner<'tcx, K>
 where
     K: Eq + Hash + Copy,
 {
-    state: &'a QueryState<'tcx, K>,
+    state: &'tcx QueryState<'tcx, K>,
     key: K,
 }
 
@@ -181,7 +181,7 @@ where
     }
 }
 
-impl<'a, 'tcx, K> JobOwner<'a, 'tcx, K>
+impl<'tcx, K> JobOwner<'tcx, K>
 where
     K: Eq + Hash + Copy,
 {
@@ -218,7 +218,7 @@ where
     }
 }
 
-impl<'a, 'tcx, K> Drop for JobOwner<'a, 'tcx, K>
+impl<'tcx, K> Drop for JobOwner<'tcx, K>
 where
     K: Eq + Hash + Copy,
 {
@@ -422,7 +422,7 @@ where
 fn execute_job<'tcx, Q, const INCR: bool>(
     query: Q,
     qcx: Q::Qcx,
-    state: &QueryState<'tcx, Q::Key>,
+    state: &'tcx QueryState<'tcx, Q::Key>,
     key: Q::Key,
     key_hash: u64,
     id: QueryJobId,