1 files changed, 24 insertions, 28 deletions
diff --git a/compiler/rustc_middle/src/ty/assoc.rs b/compiler/rustc_middle/src/ty/assoc.rs
index e18737c0d7c..c97156ac17f 100644
--- a/compiler/rustc_middle/src/ty/assoc.rs
+++ b/compiler/rustc_middle/src/ty/assoc.rs
@@ -1,6 +1,6 @@
 pub use self::AssocItemContainer::*;
 
-use crate::ty;
+use crate::ty::{self, DefIdTree};
 use rustc_data_structures::sorted_map::SortedIndexMultiMap;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Namespace};
@@ -11,33 +11,8 @@ use super::{TyCtxt, Visibility};
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable, Hash, Encodable, Decodable)]
 pub enum AssocItemContainer {
-    TraitContainer(DefId),
-    ImplContainer(DefId),
-}
-
-impl AssocItemContainer {
-    pub fn impl_def_id(&self) -> Option<DefId> {
-        match *self {
-            ImplContainer(id) => Some(id),
-            _ => None,
-        }
-    }
-
-    /// Asserts that this is the `DefId` of an associated item declared
-    /// in a trait, and returns the trait `DefId`.
-    pub fn assert_trait(&self) -> DefId {
-        match *self {
-            TraitContainer(id) => id,
-            _ => bug!("associated item has wrong container type: {:?}", self),
-        }
-    }
-
-    pub fn id(&self) -> DefId {
-        match *self {
-            TraitContainer(id) => id,
-            ImplContainer(id) => id,
-        }
-    }
+    TraitContainer,
+    ImplContainer,
 }
 
 /// Information about an associated item
@@ -71,6 +46,27 @@ impl AssocItem {
         tcx.visibility(self.def_id)
     }
 
+    #[inline]
+    pub fn container_id(&self, tcx: TyCtxt<'_>) -> DefId {
+        tcx.parent(self.def_id)
+    }
+
+    #[inline]
+    pub fn trait_container(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
+        match self.container {
+            AssocItemContainer::ImplContainer => None,
+            AssocItemContainer::TraitContainer => Some(tcx.parent(self.def_id)),
+        }
+    }
+
+    #[inline]
+    pub fn impl_container(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
+        match self.container {
+            AssocItemContainer::ImplContainer => Some(tcx.parent(self.def_id)),
+            AssocItemContainer::TraitContainer => None,
+        }
+    }
+
     pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
         match self.kind {
             ty::AssocKind::Fn => {