Remove QueryEngine trait

compiler/rustc_incremental/src/persist/load.rs

@@ -4,7 +4,7 @@ use crate::errors;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::memmap::Mmap;
 use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
-use rustc_middle::ty::OnDiskCache;
+use rustc_middle::query::on_disk_cache::OnDiskCache;
 use rustc_serialize::opaque::MemDecoder;
 use rustc_serialize::Decodable;
 use rustc_session::config::IncrementalStateAssertion;
@@ -211,7 +211,7 @@ pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
 /// If we are not in incremental compilation mode, returns `None`.
 /// Otherwise, tries to load the query result cache from disk,
 /// creating an empty cache if it could not be loaded.
-pub fn load_query_result_cache<'a, C: OnDiskCache<'a>>(sess: &'a Session) -> Option<C> {
+pub fn load_query_result_cache(sess: &Session) -> Option<OnDiskCache<'_>> {
     if sess.opts.incremental.is_none() {
         return None;
     }
@@ -223,7 +223,9 @@ pub fn load_query_result_cache<'a, C: OnDiskCache<'a>>(sess: &'a Session) -> Opt
         &query_cache_path(sess),
         sess.is_nightly_build(),
     ) {
-        LoadResult::Ok { data: (bytes, start_pos) } => Some(C::new(sess, bytes, start_pos)),
-        _ => Some(C::new_empty(sess.source_map())),
+        LoadResult::Ok { data: (bytes, start_pos) } => {
+            Some(OnDiskCache::new(sess, bytes, start_pos))
+        }
+        _ => Some(OnDiskCache::new_empty(sess.source_map())),
     }
 }