Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -1040,11 +1040,27 @@
   unsigned Index = 0;
   for (const auto *D : Owner->noload_decls()) {
     const auto *F = dyn_cast<FieldDecl>(D);
-    if (!F || !F->isAnonymousStructOrUnion())
+    if (!F)
       continue;
-
-    if (Context.hasSameType(F->getType(), AnonTy))
-      break;
+  
+    if (F->isAnonymousStructOrUnion()) {
+      if (Context.hasSameType(F->getType(), AnonTy)) {
+        break;
+      }
+    } else {
+      // If the field looks like this:
+      // struct { ... } A;
+      QualType FieldType = F->getType();
+      if (const RecordType *RecType = dyn_cast<RecordType>(FieldType)) {
+        const RecordDecl *RecDecl = RecType->getDecl();
+        if (RecDecl->getDeclContext() == Owner &&
+            !RecDecl->getIdentifier()) {
+          if (Context.hasSameType(FieldType, AnonTy)) {
+            break;
+          }
+        }
+      }
+    }
 
     ++Index;
   }
Index: test/ASTMerge/Inputs/anonymous-fields1.cpp
===================================================================
--- /dev/null
+++ test/ASTMerge/Inputs/anonymous-fields1.cpp
@@ -0,0 +1,5 @@
+class A {
+public:
+  struct { int foo; } f;
+  struct { int foo; } g;
+};
Index: test/ASTMerge/Inputs/anonymous-fields2.cpp
===================================================================
--- /dev/null
+++ test/ASTMerge/Inputs/anonymous-fields2.cpp
@@ -0,0 +1,9 @@
+class A {
+public:
+  struct { int foo; } f;
+  struct { int foo; } g;
+};
+
+inline int useA(A &a) {
+  return (a.f.foo + a.g.foo);
+}
Index: test/ASTMerge/anonymous-fields.cpp
===================================================================
--- /dev/null
+++ test/ASTMerge/anonymous-fields.cpp
@@ -0,0 +1,4 @@
+// RUN: %clang_cc1 -emit-pch -o %t.1.ast %S/Inputs/anonymous-fields1.cpp
+// RUN: %clang_cc1 -emit-pch -o %t.2.ast %S/Inputs/anonymous-fields2.cpp
+// RUN: %clang_cc1 -emit-obj -o /dev/null -ast-merge %t.1.ast -ast-merge %t.2.ast %s
+// expected-no-diagnostics