diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index b3e92d7..c8c3815 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -13634,5 +13634,6 @@
             dyn_cast<ObjCImplementationDecl>(D)) {
     D = ID->getClassInterface();
   }
-  return D->getAvailability();
+  // Recover from user error.
+  return D ? D->getAvailability() : AR_Available;
 }