trait_of_item

src/librustc/dep_graph/dep_node.rs

@@ -156,6 +156,7 @@ pub enum DepNode<D: Clone + Debug> {
     Deprecation(D),
     ItemBodyNestedBodies(D),
     ConstIsRvaluePromotableToStatic(D),
+    TraitOfItem(D),
     IsMirAvailable(D),
     ItemAttrs(D),
     FnArgNames(D),
@@ -271,6 +272,7 @@ impl<D: Clone + Debug> DepNode<D> {
             Deprecation(ref d) => op(d).map(Deprecation),
             ItemAttrs(ref d) => op(d).map(ItemAttrs),
             FnArgNames(ref d) => op(d).map(FnArgNames),
+            TraitOfItem(ref d) => op(d).map(TraitOfItem),
             ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
             ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
             IsMirAvailable(ref d) => op(d).map(IsMirAvailable),

src/librustc/middle/cstore.rs

@@ -191,7 +191,6 @@ pub trait CrateStore {
     fn impl_parent(&self, impl_def_id: DefId) -> Option<DefId>;
 
     // trait/impl-item info
-    fn trait_of_item(&self, def_id: DefId) -> Option<DefId>;
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem;
 
     // flags
@@ -316,7 +315,6 @@ impl CrateStore for DummyCrateStore {
     fn impl_parent(&self, def: DefId) -> Option<DefId> { bug!("impl_parent") }
 
     // trait/impl-item info
-    fn trait_of_item(&self, def_id: DefId) -> Option<DefId> { bug!("trait_of_item") }
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem
         { bug!("associated_item_cloned") }
 

src/librustc/ty/maps.rs

@@ -347,6 +347,12 @@ impl<'tcx> QueryDescription for queries::fn_arg_names<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::trait_of_item<'tcx> {
+    fn describe(_: TyCtxt, _: DefId) -> String {
+        bug!("trait_of_item")
+    }
+}
+
 impl<'tcx> QueryDescription for queries::item_body_nested_bodies<'tcx> {
     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
         format!("nested item bodies of `{}`", tcx.item_path_str(def_id))
@@ -798,6 +804,7 @@ define_maps! { <'tcx>
     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
     [] item_attrs: ItemAttrs(DefId) -> Rc<[ast::Attribute]>,
     [] fn_arg_names: FnArgNames(DefId) -> Vec<ast::Name>,
+    [] trait_of_item: TraitOfItem(DefId) -> Option<DefId>,
     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
     [] is_mir_available: IsMirAvailable(DefId) -> bool,

src/librustc/ty/mod.rs

@@ -2430,22 +2430,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// If the given def ID describes an item belonging to a trait,
-    /// return the ID of the trait that the trait item belongs to.
-    /// Otherwise, return `None`.
-    pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
-        if def_id.krate != LOCAL_CRATE {
-            return self.sess.cstore.trait_of_item(def_id);
-        }
-        self.opt_associated_item(def_id)
-            .and_then(|associated_item| {
-                match associated_item.container {
-                    TraitContainer(def_id) => Some(def_id),
-                    ImplContainer(_) => None
-                }
-            })
-    }
-
     /// Construct a parameter environment suitable for static contexts or other contexts where there
     /// are no free type/lifetime parameters in scope.
     pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
@@ -2693,6 +2677,23 @@ fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
     tcx.hir.span_if_local(def_id).unwrap()
 }
 
+/// If the given def ID describes an item belonging to a trait,
+/// return the ID of the trait that the trait item belongs to.
+/// Otherwise, return `None`.
+fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
+    if def_id.krate != LOCAL_CRATE {
+        return None
+    }
+    tcx.opt_associated_item(def_id)
+        .and_then(|associated_item| {
+            match associated_item.container {
+                TraitContainer(def_id) => Some(def_id),
+                ImplContainer(_) => None
+            }
+        })
+}
+
+
 pub fn provide(providers: &mut ty::maps::Providers) {
     *providers = ty::maps::Providers {
         associated_item,
@@ -2700,6 +2701,7 @@ pub fn provide(providers: &mut ty::maps::Providers) {
         adt_sized_constraint,
         adt_dtorck_constraint,
         def_span,
+        trait_of_item,
         ..*providers
     };
 }

src/librustc_const_eval/eval.rs

@@ -74,7 +74,7 @@ pub fn lookup_const_by_id<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 // constants, we only try to find the expression for a
                 // trait-associated const if the caller gives us the
                 // substitutions for the reference to it.
-                if tcx.sess.cstore.trait_of_item(def_id).is_some() {
+                if tcx.trait_of_item(def_id).is_some() {
                     resolve_trait_associated_const(tcx, def_id, substs)
                 } else {
                     Some((def_id, substs))

src/librustc_metadata/cstore_impl.rs

@@ -119,6 +119,7 @@ provide! { <'tcx> tcx, def_id, cdata
     // This is only used by rustdoc anyway, which shouldn't have
     // incremental recompilation ever enabled.
     fn_arg_names => { cdata.get_fn_arg_names(def_id.index) }
+    trait_of_item => { cdata.get_trait_of_item(def_id.index) }
     item_body_nested_bodies => {
         let map: BTreeMap<_, _> = cdata.entry(def_id.index).ast.into_iter().flat_map(|ast| {
             ast.decode(cdata).nested_bodies.decode(cdata).map(|body| (body.id(), body))
@@ -174,11 +175,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(impl_def.krate).get_parent_impl(impl_def.index)
     }
 
-    fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
-        self.dep_graph.read(DepNode::MetaData(def_id));
-        self.get_crate_data(def_id.krate).get_trait_of_item(def_id.index)
-    }
-
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem
     {
         self.dep_graph.read(DepNode::MetaData(def));