Index: clang/lib/AST/ASTImporter.cpp
===================================================================
--- clang/lib/AST/ASTImporter.cpp
+++ clang/lib/AST/ASTImporter.cpp
@@ -3861,7 +3861,9 @@
           ASTImporter::getFieldIndex(D) !=
           ASTImporter::getFieldIndex(FoundField))
         continue;
-
+      if (D->isAnonymousStructOrUnion() && FoundField->isAnonymousStructOrUnion()) {
+        continue;
+      }
       if (Importer.IsStructurallyEquivalent(D->getType(),
                                             FoundField->getType())) {
         Importer.MapImported(D, FoundField);
Index: clang/unittests/AST/ASTImporterTest.cpp
===================================================================
--- clang/unittests/AST/ASTImporterTest.cpp
+++ clang/unittests/AST/ASTImporterTest.cpp
@@ -2462,6 +2462,36 @@
                 functionDecl(hasName("f"), hasDescendant(declRefExpr()))))));
 }
 
+TEST_P(ASTImporterOptionSpecificTestBase,
+       ImportAnnonymousUnionInClassTest) {
+  const char *Code =
+      R"(
+      class B{
+
+      public:
+
+        B(){
+          c=1;
+        }
+
+        void foo1(){}
+
+      private:
+        union{
+          int a;
+          int b;
+        };
+        union {
+          int c;
+          int d;
+        };
+      };
+      )";
+  Decl *FromTU = getTuDecl(Code, Lang_CXX11);
+  EXPECT_TRUE(FromTU);
+}
+
+
 struct ImportFunctionTemplates : ASTImporterOptionSpecificTestBase {};
 
 TEST_P(ImportFunctionTemplates, ImportFunctionTemplateInRecordDeclTwice) {