diff --git a/src/librustc/ty/maps/config.rs b/src/librustc/ty/maps/config.rs
index 5ca951d0fb3..f2fe12dedc2 100644
--- a/src/librustc/ty/maps/config.rs
+++ b/src/librustc/ty/maps/config.rs
@@ -102,7 +102,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::type_param_predicates<'tcx> {
 }
 
 impl<'tcx> QueryDescription<'tcx> for queries::coherent_trait<'tcx> {
-    fn describe(tcx: TyCtxt, (_, def_id): (CrateNum, DefId)) -> String {
+    fn describe(tcx: TyCtxt, def_id: DefId) -> String {
         format!("coherence checking all impls of trait `{}`",
                 tcx.item_path_str(def_id))
     }
diff --git a/src/librustc/ty/maps/mod.rs b/src/librustc/ty/maps/mod.rs
index 23531b7b942..7c9d274e1fe 100644
--- a/src/librustc/ty/maps/mod.rs
+++ b/src/librustc/ty/maps/mod.rs
@@ -187,7 +187,7 @@ define_maps! { <'tcx>
 
     [] fn has_typeck_tables: HasTypeckTables(DefId) -> bool,
 
-    [] fn coherent_trait: coherent_trait_dep_node((CrateNum, DefId)) -> (),
+    [] fn coherent_trait: CoherenceCheckTrait(DefId) -> (),
 
     [] fn borrowck: BorrowCheck(DefId) -> Rc<BorrowCheckResult>,
 
@@ -385,10 +385,6 @@ fn fulfill_obligation_dep_node<'tcx>((param_env, trait_ref):
     }
 }
 
-fn coherent_trait_dep_node<'tcx>((_, def_id): (CrateNum, DefId)) -> DepConstructor<'tcx> {
-    DepConstructor::CoherenceCheckTrait(def_id)
-}
-
 fn crate_inherent_impls_dep_node<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
     DepConstructor::Coherence
 }
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index 9b930233fad..85052052b32 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -11,7 +11,7 @@
 //! misc. type-system utilities too small to deserve their own file
 
 use hir::def::Def;
-use hir::def_id::{DefId, LOCAL_CRATE};
+use hir::def_id::DefId;
 use hir::map::{DefPathData, Node};
 use hir;
 use ich::NodeIdHashingMode;
@@ -427,7 +427,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             return None;
         };
 
-        self.coherent_trait((LOCAL_CRATE, drop_trait));
+        ty::maps::queries::coherent_trait::ensure(self, drop_trait);
 
         let mut dtor_did = None;
         let ty = self.type_of(adt_did);
diff --git a/src/librustc_typeck/coherence/mod.rs b/src/librustc_typeck/coherence/mod.rs
index 90a0952af04..adf154968c2 100644
--- a/src/librustc_typeck/coherence/mod.rs
+++ b/src/librustc_typeck/coherence/mod.rs
@@ -15,8 +15,8 @@
 // done by the orphan and overlap modules. Then we build up various
 // mappings. That mapping code resides here.
 
-use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
-use rustc::ty::{TyCtxt, TypeFoldable};
+use hir::def_id::{DefId, LOCAL_CRATE};
+use rustc::ty::{self, TyCtxt, TypeFoldable};
 use rustc::ty::maps::Providers;
 
 use syntax::ast;
@@ -113,8 +113,7 @@ pub fn provide(providers: &mut Providers) {
     };
 }
 
-fn coherent_trait<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                            (_, def_id): (CrateNum, DefId)) {
+fn coherent_trait<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) {
     let impls = tcx.hir.trait_impls(def_id);
     for &impl_id in impls {
         check_impl(tcx, impl_id);
@@ -127,7 +126,7 @@ fn coherent_trait<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
 pub fn check_coherence<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     for &trait_def_id in tcx.hir.krate().trait_impls.keys() {
-        tcx.coherent_trait((LOCAL_CRATE, trait_def_id));
+        ty::maps::queries::coherent_trait::ensure(tcx, trait_def_id);
     }
 
     unsafety::check(tcx);
@@ -135,6 +134,6 @@ pub fn check_coherence<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     overlap::check_auto_impls(tcx);
 
     // these queries are executed for side-effects (error reporting):
-    tcx.crate_inherent_impls(LOCAL_CRATE);
-    tcx.crate_inherent_impls_overlap_check(LOCAL_CRATE);
+    ty::maps::queries::crate_inherent_impls::ensure(tcx, LOCAL_CRATE);
+    ty::maps::queries::crate_inherent_impls_overlap_check::ensure(tcx, LOCAL_CRATE);
 }