diff --git a/clippy_lints/src/missing_doc.rs b/clippy_lints/src/missing_doc.rs
index eb4dfe8ba..7ccee73d8 100644
--- a/clippy_lints/src/missing_doc.rs
+++ b/clippy_lints/src/missing_doc.rs
@@ -177,6 +177,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
             hir::ImplItemKind::Const(..) => "an associated constant",
             hir::ImplItemKind::Method(..) => "a method",
             hir::ImplItemKind::Type(_) => "an associated type",
+            hir::ImplItemKind::Existential(_) => "an existential type",
         };
         self.check_missing_docs_attrs(cx, &impl_item.attrs, impl_item.span, desc);
     }
diff --git a/clippy_lints/src/missing_inline.rs b/clippy_lints/src/missing_inline.rs
index 0ca1c53d6..20252393f 100644
--- a/clippy_lints/src/missing_inline.rs
+++ b/clippy_lints/src/missing_inline.rs
@@ -165,7 +165,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingInline {
         let desc = match impl_item.node {
             hir::ImplItemKind::Method(..) => "a method",
             hir::ImplItemKind::Const(..) |
-            hir::ImplItemKind::Type(_) => return,
+            hir::ImplItemKind::Type(_) |
+            hir::ImplItemKind::Existential(_) => return,
         };
 
         let def_id = cx.tcx.hir.local_def_id(impl_item.id);
diff --git a/clippy_lints/src/utils/inspector.rs b/clippy_lints/src/utils/inspector.rs
index b2b99da3c..2e0f84318 100644
--- a/clippy_lints/src/utils/inspector.rs
+++ b/clippy_lints/src/utils/inspector.rs
@@ -70,6 +70,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
             },
             hir::ImplItemKind::Method(..) => println!("method"),
             hir::ImplItemKind::Type(_) => println!("associated type"),
+            hir::ImplItemKind::Existential(_) => println!("existential type"),
         }
     }
     // fn check_trait_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx
diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs
index c38a925ef..10a57e147 100644
--- a/clippy_lints/src/utils/mod.rs
+++ b/clippy_lints/src/utils/mod.rs
@@ -982,6 +982,7 @@ pub fn opt_def_id(def: Def) -> Option<DefId> {
         Def::AssociatedConst(id) |
         Def::Macro(id, ..) |
         Def::Existential(id) |
+        Def::AssociatedExistential(id) |
         Def::GlobalAsm(id) => Some(id),
 
         Def::Upvar(..) | Def::Local(_) | Def::Label(..) | Def::PrimTy(..) | Def::SelfTy(..) | Def::Err => None,