diff --git a/Cargo.lock b/Cargo.lock
index bada67eda44..eadac99787f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4308,13 +4308,17 @@ dependencies = [
  "parking_lot",
  "rustc-rayon-core",
  "rustc_arena",
+ "rustc_ast",
  "rustc_data_structures",
  "rustc_errors",
+ "rustc_feature",
+ "rustc_hir",
  "rustc_index",
  "rustc_macros",
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
+ "rustc_target",
  "smallvec",
  "tracing",
 ]
diff --git a/compiler/rustc_middle/src/ich.rs b/compiler/rustc_middle/src/ich.rs
new file mode 100644
index 00000000000..f0b869558bc
--- /dev/null
+++ b/compiler/rustc_middle/src/ich.rs
@@ -0,0 +1,5 @@
+//! ICH - Incremental Compilation Hash
+
+pub use rustc_query_system::ich::{NodeIdHashingMode, StableHashingContext};
+
+mod impls_ty;
diff --git a/compiler/rustc_middle/src/ich/impls_ty.rs b/compiler/rustc_middle/src/ich/impls_ty.rs
index 3b0640eb98d..97106b58e0a 100644
--- a/compiler/rustc_middle/src/ich/impls_ty.rs
+++ b/compiler/rustc_middle/src/ich/impls_ty.rs
@@ -1,7 +1,7 @@
 //! This module contains `HashStable` implementations for various data types
 //! from `rustc_middle::ty` in no particular order.
 
-use crate::ich::{NodeIdHashingMode, StableHashingContext};
+use crate::ich::StableHashingContext;
 use crate::middle::region;
 use crate::mir;
 use crate::ty;
@@ -163,37 +163,3 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for region::Scope {
         *self
     }
 }
-
-impl<'a> HashStable<StableHashingContext<'a>> for ty::TyVid {
-    fn hash_stable(&self, _hcx: &mut StableHashingContext<'a>, _hasher: &mut StableHasher) {
-        // `TyVid` values are confined to an inference context and hence
-        // should not be hashed.
-        bug!("ty::TyKind::hash_stable() - can't hash a TyVid {:?}.", *self)
-    }
-}
-
-impl<'a> HashStable<StableHashingContext<'a>> for ty::IntVid {
-    fn hash_stable(&self, _hcx: &mut StableHashingContext<'a>, _hasher: &mut StableHasher) {
-        // `IntVid` values are confined to an inference context and hence
-        // should not be hashed.
-        bug!("ty::TyKind::hash_stable() - can't hash an IntVid {:?}.", *self)
-    }
-}
-
-impl<'a> HashStable<StableHashingContext<'a>> for ty::FloatVid {
-    fn hash_stable(&self, _hcx: &mut StableHashingContext<'a>, _hasher: &mut StableHasher) {
-        // `FloatVid` values are confined to an inference context and hence
-        // should not be hashed.
-        bug!("ty::TyKind::hash_stable() - can't hash a FloatVid {:?}.", *self)
-    }
-}
-
-impl<'a> HashStable<StableHashingContext<'a>> for crate::middle::privacy::AccessLevels {
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| {
-            let crate::middle::privacy::AccessLevels { ref map } = *self;
-
-            map.hash_stable(hcx, hasher);
-        });
-    }
-}
diff --git a/compiler/rustc_middle/src/middle/privacy.rs b/compiler/rustc_middle/src/middle/privacy.rs
index a11ca74b25e..f33bd3438b9 100644
--- a/compiler/rustc_middle/src/middle/privacy.rs
+++ b/compiler/rustc_middle/src/middle/privacy.rs
@@ -3,7 +3,9 @@
 //! which are available for use externally when compiled as a library.
 
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_macros::HashStable;
+use rustc_query_system::ich::{NodeIdHashingMode, StableHashingContext};
 use rustc_span::def_id::LocalDefId;
 use std::hash::Hash;
 
@@ -53,3 +55,12 @@ impl<Id> Default for AccessLevels<Id> {
         AccessLevels { map: Default::default() }
     }
 }
+
+impl<'a> HashStable<StableHashingContext<'a>> for AccessLevels {
+    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
+        hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| {
+            let AccessLevels { ref map } = *self;
+            map.hash_stable(hcx, hasher);
+        });
+    }
+}
diff --git a/compiler/rustc_query_system/Cargo.toml b/compiler/rustc_query_system/Cargo.toml
index 11c18a497e5..898a8caa3ca 100644
--- a/compiler/rustc_query_system/Cargo.toml
+++ b/compiler/rustc_query_system/Cargo.toml
@@ -10,12 +10,16 @@ doctest = false
 rustc_arena = { path = "../rustc_arena" }
 tracing = "0.1"
 rustc-rayon-core = "0.3.1"
+rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
-rustc_macros = { path = "../rustc_macros" }
+rustc_feature = { path = "../rustc_feature" }
+rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
+rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
 parking_lot = "0.11"
 smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
diff --git a/compiler/rustc_middle/src/ich/hcx.rs b/compiler/rustc_query_system/src/ich/hcx.rs
similarity index 98%
rename from compiler/rustc_middle/src/ich/hcx.rs
rename to compiler/rustc_query_system/src/ich/hcx.rs
index 98dcd62f795..d3e5189ce76 100644
--- a/compiler/rustc_middle/src/ich/hcx.rs
+++ b/compiler/rustc_query_system/src/ich/hcx.rs
@@ -206,4 +206,4 @@ impl<'a> rustc_span::HashStableContext for StableHashingContext<'a> {
     }
 }
 
-impl rustc_session::HashStableContext for StableHashingContext<'a> {}
+impl<'a> rustc_session::HashStableContext for StableHashingContext<'a> {}
diff --git a/compiler/rustc_middle/src/ich/impls_hir.rs b/compiler/rustc_query_system/src/ich/impls_hir.rs
similarity index 100%
rename from compiler/rustc_middle/src/ich/impls_hir.rs
rename to compiler/rustc_query_system/src/ich/impls_hir.rs
diff --git a/compiler/rustc_middle/src/ich/impls_syntax.rs b/compiler/rustc_query_system/src/ich/impls_syntax.rs
similarity index 100%
rename from compiler/rustc_middle/src/ich/impls_syntax.rs
rename to compiler/rustc_query_system/src/ich/impls_syntax.rs
diff --git a/compiler/rustc_middle/src/ich/mod.rs b/compiler/rustc_query_system/src/ich/mod.rs
similarity index 96%
rename from compiler/rustc_middle/src/ich/mod.rs
rename to compiler/rustc_query_system/src/ich/mod.rs
index c91b6a8540b..54416902e5f 100644
--- a/compiler/rustc_middle/src/ich/mod.rs
+++ b/compiler/rustc_query_system/src/ich/mod.rs
@@ -4,10 +4,8 @@ pub use self::hcx::{NodeIdHashingMode, StableHashingContext};
 use rustc_span::symbol::{sym, Symbol};
 
 mod hcx;
-
 mod impls_hir;
 mod impls_syntax;
-mod impls_ty;
 
 pub const IGNORED_ATTRIBUTES: &[Symbol] = &[
     sym::cfg,
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index c205f0fb531..bc23de069b0 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -1,3 +1,4 @@
+#![feature(assert_matches)]
 #![feature(bool_to_option)]
 #![feature(core_intrinsics)]
 #![feature(hash_raw_entry)]
@@ -14,4 +15,5 @@ extern crate rustc_macros;
 
 pub mod cache;
 pub mod dep_graph;
+pub mod ich;
 pub mod query;
diff --git a/compiler/rustc_session/src/lib.rs b/compiler/rustc_session/src/lib.rs
index d5f887f935b..6c86f86ecd9 100644
--- a/compiler/rustc_session/src/lib.rs
+++ b/compiler/rustc_session/src/lib.rs
@@ -1,4 +1,5 @@
 #![feature(crate_visibility_modifier)]
+#![feature(min_specialization)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]