Index: cfe/trunk/lib/Sema/SemaInit.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaInit.cpp
+++ cfe/trunk/lib/Sema/SemaInit.cpp
@@ -2237,6 +2237,10 @@
     }
 
     unsigned FieldIndex = 0;
+
+    if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
+      FieldIndex = CXXRD->getNumBases();
+
     for (auto *FI : RT->getDecl()->fields()) {
       if (FI->isUnnamedBitfield())
         continue;
Index: cfe/trunk/test/SemaCXX/designated-initializers-base-class.cpp
===================================================================
--- cfe/trunk/test/SemaCXX/designated-initializers-base-class.cpp
+++ cfe/trunk/test/SemaCXX/designated-initializers-base-class.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 %s -std=c++1z -fsyntax-only -verify -Winitializer-overrides
+// expected-no-diagnostics
+
+struct B {
+  int x;
+};
+
+struct D : B {
+  int y;
+};
+
+void test() { D d = {1, .y = 2}; }