diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index f0c85fec4ea6..9ed92a77431b 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -51,6 +51,7 @@
 #![feature(range_bounds_is_empty)]
 #![feature(rustc_attrs)]
 #![feature(sized_hierarchy)]
+#![feature(trait_alias)]
 #![feature(try_blocks)]
 #![feature(try_trait_v2)]
 #![feature(try_trait_v2_residual)]
diff --git a/compiler/rustc_query_system/src/query/caches.rs b/compiler/rustc_middle/src/query/caches.rs
similarity index 99%
rename from compiler/rustc_query_system/src/query/caches.rs
rename to compiler/rustc_middle/src/query/caches.rs
index c1f5e5b67085..7424492ddc1f 100644
--- a/compiler/rustc_query_system/src/query/caches.rs
+++ b/compiler/rustc_middle/src/query/caches.rs
@@ -7,10 +7,10 @@ use rustc_data_structures::stable_hasher::HashStable;
 pub use rustc_data_structures::vec_cache::VecCache;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_index::Idx;
+use rustc_query_system::ich::StableHashingContext;
 use rustc_span::def_id::{DefId, DefIndex};
 
 use crate::dep_graph::DepNodeIndex;
-use crate::ich::StableHashingContext;
 
 /// Traits that all query keys must satisfy.
 pub trait QueryCacheKey = Hash + Eq + Copy + Debug + for<'a> HashStable<StableHashingContext<'a>>;
diff --git a/compiler/rustc_middle/src/query/inner.rs b/compiler/rustc_middle/src/query/inner.rs
index 594286bfa574..519259d92ea8 100644
--- a/compiler/rustc_middle/src/query/inner.rs
+++ b/compiler/rustc_middle/src/query/inner.rs
@@ -2,10 +2,11 @@
 //! `tcx.$query(..)` and its variations.
 
 use rustc_query_system::dep_graph::{DepKind, DepNodeKey};
-use rustc_query_system::query::{QueryCache, QueryMode};
+use rustc_query_system::query::QueryMode;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span};
 
 use crate::dep_graph;
+use crate::query::QueryCache;
 use crate::query::erase::{self, Erasable, Erased};
 use crate::query::plumbing::QueryVTable;
 use crate::ty::TyCtxt;
diff --git a/compiler/rustc_middle/src/query/keys.rs b/compiler/rustc_middle/src/query/keys.rs
index cccb7d51bd3e..d2057e86ddda 100644
--- a/compiler/rustc_middle/src/query/keys.rs
+++ b/compiler/rustc_middle/src/query/keys.rs
@@ -6,11 +6,11 @@ use rustc_ast::tokenstream::TokenStream;
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE, LocalDefId, LocalModDefId};
 use rustc_hir::hir_id::OwnerId;
 use rustc_query_system::dep_graph::DepNodeIndex;
-use rustc_query_system::query::{DefIdCache, DefaultCache, SingleCache, VecCache};
 use rustc_span::{DUMMY_SP, Ident, LocalExpnId, Span, Symbol};
 
 use crate::infer::canonical::CanonicalQueryInput;
 use crate::mir::mono::CollectionMode;
+use crate::query::{DefIdCache, DefaultCache, SingleCache, VecCache};
 use crate::ty::fast_reject::SimplifiedType;
 use crate::ty::layout::ValidityRequirement;
 use crate::ty::{self, GenericArg, GenericArgsRef, Ty, TyCtxt};
@@ -28,7 +28,7 @@ pub trait Key: Sized {
     /// In practice the cache type must implement [`QueryCache`], though that
     /// constraint is not enforced here.
     ///
-    /// [`QueryCache`]: rustc_query_system::query::QueryCache
+    /// [`QueryCache`]: rustc_middle::query::QueryCache
     type Cache<V> = DefaultCache<Self, V>;
 
     /// In the event that a cycle occurs, if no explicit span has been
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 7083f160bd77..bbd2442ec6a5 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1,6 +1,9 @@
 use rustc_hir::def_id::LocalDefId;
 pub use rustc_query_system::query::QueryMode;
 
+pub use self::caches::{
+    DefIdCache, DefaultCache, QueryCache, QueryCacheKey, SingleCache, VecCache,
+};
 pub use self::job::{QueryInfo, QueryJob, QueryJobId, QueryLatch, QueryWaiter};
 pub use self::keys::{AsLocalKey, Key, LocalCrate};
 pub use self::plumbing::{
@@ -12,6 +15,7 @@ pub use crate::queries::Providers;
 use crate::ty::TyCtxt;
 
 pub(crate) mod arena_cached;
+mod caches;
 pub mod erase;
 pub(crate) mod inner;
 mod job;
diff --git a/compiler/rustc_middle/src/query/plumbing.rs b/compiler/rustc_middle/src/query/plumbing.rs
index f2021978aad7..b5b7e0482b31 100644
--- a/compiler/rustc_middle/src/query/plumbing.rs
+++ b/compiler/rustc_middle/src/query/plumbing.rs
@@ -9,7 +9,7 @@ use rustc_hir::hir_id::OwnerId;
 use rustc_macros::HashStable;
 use rustc_query_system::dep_graph::{DepNodeIndex, SerializedDepNodeIndex};
 use rustc_query_system::ich::StableHashingContext;
-use rustc_query_system::query::{CycleErrorHandling, QueryCache};
+use rustc_query_system::query::CycleErrorHandling;
 use rustc_span::{ErrorGuaranteed, Span};
 pub use sealed::IntoQueryParam;
 
@@ -20,7 +20,7 @@ use crate::queries::{
 };
 use crate::query::on_disk_cache::{CacheEncoder, EncodedDepNodeIndex, OnDiskCache};
 use crate::query::stack::{QueryStackDeferred, QueryStackFrame, QueryStackFrameExtra};
-use crate::query::{QueryInfo, QueryJob};
+use crate::query::{QueryCache, QueryInfo, QueryJob};
 use crate::ty::TyCtxt;
 
 /// For a particular query, keeps track of "active" keys, i.e. keys whose
diff --git a/compiler/rustc_query_impl/src/dep_kind_vtables.rs b/compiler/rustc_query_impl/src/dep_kind_vtables.rs
index 92fd9c6734d0..aa29313bcd32 100644
--- a/compiler/rustc_query_impl/src/dep_kind_vtables.rs
+++ b/compiler/rustc_query_impl/src/dep_kind_vtables.rs
@@ -1,8 +1,8 @@
 use rustc_middle::bug;
 use rustc_middle::dep_graph::DepKindVTable;
+use rustc_middle::query::QueryCache;
 use rustc_middle::ty::TyCtxt;
 use rustc_query_system::dep_graph::{DepNodeKey, FingerprintStyle};
-use rustc_query_system::query::QueryCache;
 
 use crate::plumbing::{force_from_dep_node_inner, try_load_from_on_disk_cache_inner};
 use crate::{QueryCtxt, QueryDispatcherUnerased, QueryFlags};
diff --git a/compiler/rustc_query_impl/src/execution.rs b/compiler/rustc_query_impl/src/execution.rs
index 38150c154e08..2d092b741e3e 100644
--- a/compiler/rustc_query_impl/src/execution.rs
+++ b/compiler/rustc_query_impl/src/execution.rs
@@ -7,14 +7,12 @@ use rustc_data_structures::{outline, sharded, sync};
 use rustc_errors::{Diag, FatalError, StashKey};
 use rustc_middle::dep_graph::DepsType;
 use rustc_middle::query::{
-    ActiveKeyStatus, CycleError, QueryJob, QueryJobId, QueryLatch, QueryStackDeferred,
+    ActiveKeyStatus, CycleError, QueryCache, QueryJob, QueryJobId, QueryLatch, QueryStackDeferred,
     QueryStackFrame, QueryState,
 };
 use rustc_middle::ty::TyCtxt;
 use rustc_query_system::dep_graph::{DepGraphData, DepNodeKey, HasDepContext};
-use rustc_query_system::query::{
-    CycleErrorHandling, QueryCache, QueryMode, incremental_verify_ich,
-};
+use rustc_query_system::query::{CycleErrorHandling, QueryMode, incremental_verify_ich};
 use rustc_span::{DUMMY_SP, Span};
 
 use crate::dep_graph::{DepContext, DepNode, DepNodeIndex};
diff --git a/compiler/rustc_query_impl/src/lib.rs b/compiler/rustc_query_impl/src/lib.rs
index 02a86b5a4c65..90e442f33448 100644
--- a/compiler/rustc_query_impl/src/lib.rs
+++ b/compiler/rustc_query_impl/src/lib.rs
@@ -20,10 +20,10 @@ use rustc_middle::query::on_disk_cache::{CacheEncoder, EncodedDepNodeIndex, OnDi
 use rustc_middle::query::plumbing::{
     HashResult, QueryState, QuerySystem, QuerySystemFns, QueryVTable,
 };
-use rustc_middle::query::{AsLocalKey, CycleError};
+use rustc_middle::query::{AsLocalKey, CycleError, QueryCache};
 use rustc_middle::ty::TyCtxt;
 use rustc_query_system::dep_graph::SerializedDepNodeIndex;
-use rustc_query_system::query::{CycleErrorHandling, QueryCache, QueryMode};
+use rustc_query_system::query::{CycleErrorHandling, QueryMode};
 use rustc_span::{ErrorGuaranteed, Span};
 
 pub use crate::dep_kind_vtables::make_dep_kind_vtables;
diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
index 1d549c6ecc69..438195a22fdf 100644
--- a/compiler/rustc_query_impl/src/plumbing.rs
+++ b/compiler/rustc_query_impl/src/plumbing.rs
@@ -23,14 +23,14 @@ use rustc_middle::query::on_disk_cache::{
 };
 use rustc_middle::query::plumbing::QueryVTable;
 use rustc_middle::query::{
-    Key, QueryJobId, QueryStackDeferred, QueryStackFrame, QueryStackFrameExtra,
+    Key, QueryCache, QueryJobId, QueryStackDeferred, QueryStackFrame, QueryStackFrameExtra,
 };
 use rustc_middle::ty::codec::TyEncoder;
 use rustc_middle::ty::print::with_reduced_queries;
 use rustc_middle::ty::tls::{self, ImplicitCtxt};
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_query_system::dep_graph::{DepNodeKey, HasDepContext};
-use rustc_query_system::query::{QueryCache, QueryContext, QuerySideEffect};
+use rustc_query_system::query::{QueryContext, QuerySideEffect};
 use rustc_serialize::{Decodable, Encodable};
 use rustc_span::def_id::LOCAL_CRATE;
 
diff --git a/compiler/rustc_query_impl/src/profiling_support.rs b/compiler/rustc_query_impl/src/profiling_support.rs
index 7be75ea88aca..679fee49b6c6 100644
--- a/compiler/rustc_query_impl/src/profiling_support.rs
+++ b/compiler/rustc_query_impl/src/profiling_support.rs
@@ -6,8 +6,8 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::profiling::SelfProfiler;
 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE, LocalDefId};
 use rustc_hir::definitions::DefPathData;
+use rustc_middle::query::QueryCache;
 use rustc_middle::ty::TyCtxt;
-use rustc_query_system::query::QueryCache;
 
 pub(crate) struct QueryKeyStringCache {
     def_id_cache: FxHashMap<DefId, StringId>,
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index e8d857cf3178..c968c4f64cb7 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -2,7 +2,6 @@
 #![allow(internal_features)]
 #![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(min_specialization)]
-#![feature(trait_alias)]
 // tidy-alphabetical-end
 
 pub mod dep_graph;
diff --git a/compiler/rustc_query_system/src/query/mod.rs b/compiler/rustc_query_system/src/query/mod.rs
index 8b84c1023b01..5d6f2669c2f2 100644
--- a/compiler/rustc_query_system/src/query/mod.rs
+++ b/compiler/rustc_query_system/src/query/mod.rs
@@ -4,13 +4,9 @@ use rustc_data_structures::jobserver::Proxy;
 use rustc_errors::DiagInner;
 use rustc_macros::{Decodable, Encodable};
 
-pub use self::caches::{
-    DefIdCache, DefaultCache, QueryCache, QueryCacheKey, SingleCache, VecCache,
-};
 pub use self::plumbing::*;
 use crate::dep_graph::{DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
 
-mod caches;
 mod plumbing;
 
 /// How a particular query deals with query cycle errors.