diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index e708950c69ef..305b64f3320c 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -336,121 +336,123 @@ pub struct DummyCrateStore;
 #[allow(unused_variables)]
 impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     // item info
-    fn stability(&self, def: DefId) -> Option<attr::Stability> { unimplemented!() }
-    fn deprecation(&self, def: DefId) -> Option<attr::Deprecation> { unimplemented!() }
-    fn visibility(&self, def: DefId) -> hir::Visibility { unimplemented!() }
+    fn stability(&self, def: DefId) -> Option<attr::Stability> { bug!("stability") }
+    fn deprecation(&self, def: DefId) -> Option<attr::Deprecation> { bug!("deprecation") }
+    fn visibility(&self, def: DefId) -> hir::Visibility { bug!("visibility") }
     fn closure_kind(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)
-                    -> ty::ClosureKind  { unimplemented!() }
+                    -> ty::ClosureKind  { bug!("closure_kind") }
     fn closure_ty(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)
-                  -> ty::ClosureTy<'tcx>  { unimplemented!() }
-    fn item_variances(&self, def: DefId) -> ty::ItemVariances { unimplemented!() }
-    fn repr_attrs(&self, def: DefId) -> Vec<attr::ReprAttr> { unimplemented!() }
+                  -> ty::ClosureTy<'tcx>  { bug!("closure_ty") }
+    fn item_variances(&self, def: DefId) -> ty::ItemVariances { bug!("item_variances") }
+    fn repr_attrs(&self, def: DefId) -> Vec<attr::ReprAttr> { bug!("repr_attrs") }
     fn item_type(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                 -> ty::TypeScheme<'tcx> { unimplemented!() }
-    fn relative_item_path(&self, def: DefId) -> Vec<hir_map::PathElem> { unimplemented!() }
+                 -> ty::TypeScheme<'tcx> { bug!("item_type") }
+    fn relative_item_path(&self, def: DefId)
+                          -> Vec<hir_map::PathElem> { bug!("relative_item_path") }
     fn visible_parent_map<'a>(&'a self) -> ::std::cell::RefMut<'a, DefIdMap<DefId>> {
-        unimplemented!()
+        bug!("visible_parent_map")
     }
-    fn extern_item_path(&self, def: DefId) -> Vec<hir_map::PathElem> { unimplemented!() }
-    fn item_name(&self, def: DefId) -> ast::Name { unimplemented!() }
+    fn extern_item_path(&self, def: DefId) -> Vec<hir_map::PathElem> { bug!("extern_item_path") }
+    fn item_name(&self, def: DefId) -> ast::Name { bug!("item_name") }
     fn item_predicates(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                       -> ty::GenericPredicates<'tcx> { unimplemented!() }
+                       -> ty::GenericPredicates<'tcx> { bug!("item_predicates") }
     fn item_super_predicates(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                             -> ty::GenericPredicates<'tcx> { unimplemented!() }
-    fn item_attrs(&self, def_id: DefId) -> Vec<ast::Attribute> { unimplemented!() }
-    fn item_symbol(&self, def: DefId) -> String { unimplemented!() }
+                             -> ty::GenericPredicates<'tcx> { bug!("item_super_predicates") }
+    fn item_attrs(&self, def_id: DefId) -> Vec<ast::Attribute> { bug!("item_attrs") }
+    fn item_symbol(&self, def: DefId) -> String { bug!("item_symbol") }
     fn trait_def(&self, tcx: &TyCtxt<'tcx>, def: DefId)-> ty::TraitDef<'tcx>
-        { unimplemented!() }
+        { bug!("trait_def") }
     fn adt_def(&self, tcx: &TyCtxt<'tcx>, def: DefId) -> ty::AdtDefMaster<'tcx>
-        { unimplemented!() }
-    fn method_arg_names(&self, did: DefId) -> Vec<String> { unimplemented!() }
+        { bug!("adt_def") }
+    fn method_arg_names(&self, did: DefId) -> Vec<String> { bug!("method_arg_names") }
     fn inherent_implementations_for_type(&self, def_id: DefId) -> Vec<DefId> { vec![] }
 
     // trait info
     fn implementations_of_trait(&self, def_id: DefId) -> Vec<DefId> { vec![] }
     fn provided_trait_methods(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                              -> Vec<Rc<ty::Method<'tcx>>> { unimplemented!() }
+                              -> Vec<Rc<ty::Method<'tcx>>> { bug!("provided_trait_methods") }
     fn trait_item_def_ids(&self, def: DefId)
-                          -> Vec<ty::ImplOrTraitItemId> { unimplemented!() }
+                          -> Vec<ty::ImplOrTraitItemId> { bug!("trait_item_def_ids") }
 
     // impl info
     fn impl_items(&self, impl_def_id: DefId) -> Vec<ty::ImplOrTraitItemId>
-        { unimplemented!() }
+        { bug!("impl_items") }
     fn impl_trait_ref(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                      -> Option<ty::TraitRef<'tcx>> { unimplemented!() }
-    fn impl_polarity(&self, def: DefId) -> Option<hir::ImplPolarity> { unimplemented!() }
+                      -> Option<ty::TraitRef<'tcx>> { bug!("impl_trait_ref") }
+    fn impl_polarity(&self, def: DefId) -> Option<hir::ImplPolarity> { bug!("impl_polarity") }
     fn custom_coerce_unsized_kind(&self, def: DefId)
                                   -> Option<ty::adjustment::CustomCoerceUnsized>
-        { unimplemented!() }
+        { bug!("custom_coerce_unsized_kind") }
     fn associated_consts(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                         -> Vec<Rc<ty::AssociatedConst<'tcx>>> { unimplemented!() }
-    fn impl_parent(&self, def: DefId) -> Option<DefId> { unimplemented!() }
+                         -> Vec<Rc<ty::AssociatedConst<'tcx>>> { bug!("associated_consts") }
+    fn impl_parent(&self, def: DefId) -> Option<DefId> { bug!("impl_parent") }
 
     // trait/impl-item info
     fn trait_of_item(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)
-                     -> Option<DefId> { unimplemented!() }
+                     -> Option<DefId> { bug!("trait_of_item") }
     fn impl_or_trait_item(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                          -> Option<ty::ImplOrTraitItem<'tcx>> { unimplemented!() }
+                          -> Option<ty::ImplOrTraitItem<'tcx>> { bug!("impl_or_trait_item") }
 
     // flags
-    fn is_const_fn(&self, did: DefId) -> bool { unimplemented!() }
-    fn is_defaulted_trait(&self, did: DefId) -> bool { unimplemented!() }
-    fn is_impl(&self, did: DefId) -> bool { unimplemented!() }
-    fn is_default_impl(&self, impl_did: DefId) -> bool { unimplemented!() }
-    fn is_extern_item(&self, tcx: &TyCtxt<'tcx>, did: DefId) -> bool { unimplemented!() }
-    fn is_static_method(&self, did: DefId) -> bool { unimplemented!() }
+    fn is_const_fn(&self, did: DefId) -> bool { bug!("is_const_fn") }
+    fn is_defaulted_trait(&self, did: DefId) -> bool { bug!("is_defaulted_trait") }
+    fn is_impl(&self, did: DefId) -> bool { bug!("is_impl") }
+    fn is_default_impl(&self, impl_did: DefId) -> bool { bug!("is_default_impl") }
+    fn is_extern_item(&self, tcx: &TyCtxt<'tcx>, did: DefId) -> bool { bug!("is_extern_item") }
+    fn is_static_method(&self, did: DefId) -> bool { bug!("is_static_method") }
     fn is_statically_included_foreign_item(&self, id: ast::NodeId) -> bool { false }
-    fn is_typedef(&self, did: DefId) -> bool { unimplemented!() }
+    fn is_typedef(&self, did: DefId) -> bool { bug!("is_typedef") }
 
     // crate metadata
     fn dylib_dependency_formats(&self, cnum: ast::CrateNum)
                                     -> Vec<(ast::CrateNum, LinkagePreference)>
-        { unimplemented!() }
+        { bug!("dylib_dependency_formats") }
     fn lang_items(&self, cnum: ast::CrateNum) -> Vec<(DefIndex, usize)>
-        { unimplemented!() }
+        { bug!("lang_items") }
     fn missing_lang_items(&self, cnum: ast::CrateNum) -> Vec<lang_items::LangItem>
-        { unimplemented!() }
-    fn is_staged_api(&self, cnum: ast::CrateNum) -> bool { unimplemented!() }
-    fn is_explicitly_linked(&self, cnum: ast::CrateNum) -> bool { unimplemented!() }
-    fn is_allocator(&self, cnum: ast::CrateNum) -> bool { unimplemented!() }
-    fn extern_crate(&self, cnum: ast::CrateNum) -> Option<ExternCrate> { unimplemented!() }
+        { bug!("missing_lang_items") }
+    fn is_staged_api(&self, cnum: ast::CrateNum) -> bool { bug!("is_staged_api") }
+    fn is_explicitly_linked(&self, cnum: ast::CrateNum) -> bool { bug!("is_explicitly_linked") }
+    fn is_allocator(&self, cnum: ast::CrateNum) -> bool { bug!("is_allocator") }
+    fn extern_crate(&self, cnum: ast::CrateNum) -> Option<ExternCrate> { bug!("extern_crate") }
     fn crate_attrs(&self, cnum: ast::CrateNum) -> Vec<ast::Attribute>
-        { unimplemented!() }
-    fn crate_name(&self, cnum: ast::CrateNum) -> InternedString { unimplemented!() }
+        { bug!("crate_attrs") }
+    fn crate_name(&self, cnum: ast::CrateNum) -> InternedString { bug!("crate_name") }
     fn original_crate_name(&self, cnum: ast::CrateNum) -> InternedString {
-        unimplemented!()
+        bug!("original_crate_name")
     }
-    fn crate_hash(&self, cnum: ast::CrateNum) -> Svh { unimplemented!() }
-    fn crate_disambiguator(&self, cnum: ast::CrateNum) -> InternedString { unimplemented!() }
+    fn crate_hash(&self, cnum: ast::CrateNum) -> Svh { bug!("crate_hash") }
+    fn crate_disambiguator(&self, cnum: ast::CrateNum)
+                           -> InternedString { bug!("crate_disambiguator") }
     fn crate_struct_field_attrs(&self, cnum: ast::CrateNum)
                                 -> FnvHashMap<DefId, Vec<ast::Attribute>>
-        { unimplemented!() }
+        { bug!("crate_struct_field_attrs") }
     fn plugin_registrar_fn(&self, cnum: ast::CrateNum) -> Option<DefId>
-        { unimplemented!() }
+        { bug!("plugin_registrar_fn") }
     fn native_libraries(&self, cnum: ast::CrateNum) -> Vec<(NativeLibraryKind, String)>
-        { unimplemented!() }
-    fn reachable_ids(&self, cnum: ast::CrateNum) -> Vec<DefId> { unimplemented!() }
+        { bug!("native_libraries") }
+    fn reachable_ids(&self, cnum: ast::CrateNum) -> Vec<DefId> { bug!("reachable_ids") }
 
     // resolve
-    fn def_key(&self, def: DefId) -> hir_map::DefKey { unimplemented!() }
-    fn relative_def_path(&self, def: DefId) -> hir_map::DefPath { unimplemented!() }
-    fn variant_kind(&self, def_id: DefId) -> Option<VariantKind> { unimplemented!() }
+    fn def_key(&self, def: DefId) -> hir_map::DefKey { bug!("def_key") }
+    fn relative_def_path(&self, def: DefId) -> hir_map::DefPath { bug!("relative_def_path") }
+    fn variant_kind(&self, def_id: DefId) -> Option<VariantKind> { bug!("variant_kind") }
     fn struct_ctor_def_id(&self, struct_def_id: DefId) -> Option<DefId>
-        { unimplemented!() }
+        { bug!("struct_ctor_def_id") }
     fn tuple_struct_definition_if_ctor(&self, did: DefId) -> Option<DefId>
-        { unimplemented!() }
-    fn struct_field_names(&self, def: DefId) -> Vec<ast::Name> { unimplemented!() }
-    fn item_children(&self, did: DefId) -> Vec<ChildItem> { unimplemented!() }
+        { bug!("tuple_struct_definition_if_ctor") }
+    fn struct_field_names(&self, def: DefId) -> Vec<ast::Name> { bug!("struct_field_names") }
+    fn item_children(&self, did: DefId) -> Vec<ChildItem> { bug!("item_children") }
     fn crate_top_level_items(&self, cnum: ast::CrateNum) -> Vec<ChildItem>
-        { unimplemented!() }
+        { bug!("crate_top_level_items") }
 
     // misc. metadata
     fn maybe_get_item_ast(&'tcx self, tcx: &TyCtxt<'tcx>, def: DefId)
-                          -> FoundAst<'tcx> { unimplemented!() }
+                          -> FoundAst<'tcx> { bug!("maybe_get_item_ast") }
     fn maybe_get_item_mir(&self, tcx: &TyCtxt<'tcx>, def: DefId)
-                          -> Option<Mir<'tcx>> { unimplemented!() }
+                          -> Option<Mir<'tcx>> { bug!("maybe_get_item_mir") }
     fn is_item_mir_available(&self, def: DefId) -> bool {
-        unimplemented!()
+        bug!("is_item_mir_available")
     }
 
     // This is basically a 1-based range of ints, which is a little
@@ -460,18 +462,18 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     fn used_link_args(&self) -> Vec<String> { vec![] }
 
     // utility functions
-    fn metadata_filename(&self) -> &str { unimplemented!() }
-    fn metadata_section_name(&self, target: &Target) -> &str { unimplemented!() }
+    fn metadata_filename(&self) -> &str { bug!("metadata_filename") }
+    fn metadata_section_name(&self, target: &Target) -> &str { bug!("metadata_section_name") }
     fn encode_type(&self,
                    tcx: &TyCtxt<'tcx>,
                    ty: Ty<'tcx>,
                    def_id_to_string: fn(&TyCtxt<'tcx>, DefId) -> String)
                    -> Vec<u8> {
-        unimplemented!()
+        bug!("encode_type")
     }
     fn used_crates(&self, prefer: LinkagePreference) -> Vec<(ast::CrateNum, Option<PathBuf>)>
         { vec![] }
-    fn used_crate_source(&self, cnum: ast::CrateNum) -> CrateSource { unimplemented!() }
+    fn used_crate_source(&self, cnum: ast::CrateNum) -> CrateSource { bug!("used_crate_source") }
     fn extern_mod_stmt_cnum(&self, emod_id: ast::NodeId) -> Option<ast::CrateNum> { None }
     fn encode_metadata(&self,
                        tcx: &TyCtxt<'tcx>,
@@ -481,7 +483,7 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
                        reachable: &NodeSet,
                        mir_map: &MirMap<'tcx>,
                        krate: &hir::Crate) -> Vec<u8> { vec![] }
-    fn metadata_encoding_version(&self) -> &[u8] { unimplemented!() }
+    fn metadata_encoding_version(&self) -> &[u8] { bug!("metadata_encoding_version") }
 }
 
 
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index 7b16d682809f..d3757629d30d 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.rs
@@ -822,7 +822,7 @@ fn early_bound_lifetime_names(generics: &hir::Generics) -> Vec<ast::Name> {
                         collector.visit_lifetime(bound);
                     }
                 }
-                &hir::WherePredicate::EqPredicate(_) => unimplemented!()
+                &hir::WherePredicate::EqPredicate(_) => bug!("unimplemented")
             }
         }
     }