diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 8ad1db785956..6597db9e19bd 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -245,7 +245,6 @@ pub trait CrateStore {
 
     // flags
     fn is_const_fn(&self, did: DefId) -> bool;
-    fn is_default_impl(&self, impl_did: DefId) -> bool;
     fn is_dllimport_foreign_item(&self, def: DefId) -> bool;
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool;
 
@@ -364,7 +363,6 @@ impl CrateStore for DummyCrateStore {
 
     // flags
     fn is_const_fn(&self, did: DefId) -> bool { bug!("is_const_fn") }
-    fn is_default_impl(&self, impl_did: DefId) -> bool { bug!("is_default_impl") }
     fn is_dllimport_foreign_item(&self, id: DefId) -> bool { false }
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool { false }
 
diff --git a/src/librustc/ty/item_path.rs b/src/librustc/ty/item_path.rs
index 16d5d1187fc8..78536b53ba87 100644
--- a/src/librustc/ty/item_path.rs
+++ b/src/librustc/ty/item_path.rs
@@ -218,7 +218,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
         // Always use types for non-local impls, where types are always
         // available, and filename/line-number is mostly uninteresting.
-        let use_types = !impl_def_id.is_local() || {
+        let use_types = !self.is_default_impl(impl_def_id) && (!impl_def_id.is_local() || {
             // Otherwise, use filename/line-number if forced.
             let force_no_types = FORCE_IMPL_FILENAME_LINE.with(|f| f.get());
             !force_no_types && {
@@ -226,7 +226,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 ty::queries::impl_trait_ref::try_get(self, DUMMY_SP, impl_def_id).is_ok() &&
                     ty::queries::type_of::try_get(self, DUMMY_SP, impl_def_id).is_ok()
             }
-        };
+        });
 
         if !use_types {
             return self.push_impl_path_fallback(buffer, impl_def_id);
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index fb352e5be893..757687f00a20 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -774,6 +774,9 @@ define_maps! { <'tcx>
     /// True if this is a foreign item (i.e., linked via `extern { ... }`).
     [] is_foreign_item: IsForeignItem(DefId) -> bool,
 
+    /// True if this is a default impl (aka impl Foo for ..)
+    [] is_default_impl: ItemSignature(DefId) -> bool,
+
     /// Get a map with the variance of every item; use `item_variance`
     /// instead.
     [] crate_variances: crate_variances(CrateNum) -> Rc<ty::CrateVariancesMap>,
diff --git a/src/librustc_borrowck/borrowck/mir/mod.rs b/src/librustc_borrowck/borrowck/mir/mod.rs
index 2eb064305e87..2b39d2a256e1 100644
--- a/src/librustc_borrowck/borrowck/mir/mod.rs
+++ b/src/librustc_borrowck/borrowck/mir/mod.rs
@@ -59,7 +59,7 @@ pub fn borrowck_mir(bcx: &mut BorrowckCtxt,
                     attributes: &[ast::Attribute]) {
     let tcx = bcx.tcx;
     let def_id = tcx.hir.local_def_id(id);
-    debug!("borrowck_mir({}) UNIMPLEMENTED", tcx.item_path_str(def_id));
+    debug!("borrowck_mir({:?}) UNIMPLEMENTED", def_id);
 
     // It is safe for us to borrow `mir_validated()`: `optimized_mir`
     // steals it, but it forces the `borrowck` query.
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index 9d098557367c..b3503713c904 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -106,6 +106,7 @@ provide! { <'tcx> tcx, def_id, cdata
     closure_type => { cdata.closure_ty(def_id.index, tcx) }
     inherent_impls => { Rc::new(cdata.get_inherent_implementations_for_type(def_id.index)) }
     is_foreign_item => { cdata.is_foreign_item(def_id.index) }
+    is_default_impl => { cdata.is_default_impl(def_id.index) }
     describe_def => { cdata.get_def(def_id.index) }
     def_span => { cdata.get_span(def_id.index, &tcx.sess) }
     stability => { cdata.get_stability(def_id.index) }
@@ -176,11 +177,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(did.krate).is_const_fn(did.index)
     }
 
-    fn is_default_impl(&self, impl_did: DefId) -> bool {
-        self.dep_graph.read(DepNode::MetaData(impl_did));
-        self.get_crate_data(impl_did.krate).is_default_impl(impl_did.index)
-    }
-
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool
     {
         self.do_is_statically_included_foreign_item(def_id)
@@ -403,7 +399,7 @@ impl CrateStore for cstore::CStore {
         }
 
         self.dep_graph.read(DepNode::MetaData(def_id));
-        debug!("item_body({}): inlining item", tcx.item_path_str(def_id));
+        debug!("item_body({:?}): inlining item", def_id);
 
         self.get_crate_data(def_id.krate).item_body(tcx, def_id.index)
     }
@@ -515,4 +511,4 @@ impl CrateStore for cstore::CStore {
         drop(visible_parent_map);
         self.visible_parent_map.borrow()
     }
-}
\ No newline at end of file
+}
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index a938e5e29cd9..3b1c54f68e49 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -361,7 +361,7 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
 
     /// Qualify a whole const, static initializer or const fn.
     fn qualify_const(&mut self) -> Qualif {
-        debug!("qualifying {} {}", self.mode, self.tcx.item_path_str(self.def_id));
+        debug!("qualifying {} {:?}", self.mode, self.def_id);
 
         let mir = self.mir;
 
diff --git a/src/librustc_mir/transform/type_check.rs b/src/librustc_mir/transform/type_check.rs
index 6d9603ea459d..8258627748f3 100644
--- a/src/librustc_mir/transform/type_check.rs
+++ b/src/librustc_mir/transform/type_check.rs
@@ -744,7 +744,7 @@ impl MirPass for TypeckMir {
                           mir: &mut Mir<'tcx>) {
         let item_id = src.item_id();
         let def_id = tcx.hir.local_def_id(item_id);
-        debug!("run_pass: {}", tcx.item_path_str(def_id));
+        debug!("run_pass: {:?}", def_id);
 
         if tcx.sess.err_count() > 0 {
             // compiling a broken program can obviously result in a
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index cb1bd3e099d5..fb3bcd31e21f 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -100,6 +100,7 @@ pub fn provide(providers: &mut Providers) {
         impl_trait_ref,
         impl_polarity,
         is_foreign_item,
+        is_default_impl,
         ..*providers
     };
 }
@@ -1545,3 +1546,14 @@ fn is_foreign_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id)
     }
 }
+
+fn is_default_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                             def_id: DefId)
+                             -> bool {
+    match tcx.hir.get_if_local(def_id) {
+        Some(hir_map::NodeItem(&hir::Item { node: hir::ItemDefaultImpl(..), .. }))
+             => true,
+        Some(_) => false,
+        _ => bug!("is_default_impl applied to non-local def-id {:?}", def_id)
+    }
+}
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 5ea3eaa88d77..8f7add14d0a0 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -290,7 +290,7 @@ pub fn build_impl(cx: &DocContext, did: DefId, ret: &mut Vec<clean::Item>) {
     }
 
     // If this is a defaulted impl, then bail out early here
-    if tcx.sess.cstore.is_default_impl(did) {
+    if tcx.is_default_impl(did) {
         return ret.push(clean::Item {
             inner: clean::DefaultImplItem(clean::DefaultImpl {
                 // FIXME: this should be decoded