Index: clang/lib/AST/DeclBase.cpp
===================================================================
--- clang/lib/AST/DeclBase.cpp
+++ clang/lib/AST/DeclBase.cpp
@@ -339,9 +339,12 @@
       return true;
     if (!isa<TagDecl>(LDC))
       return false;
-    if (const auto *CRD = dyn_cast<CXXRecordDecl>(LDC))
+    if (const auto *CRD = dyn_cast<CXXRecordDecl>(LDC)) {
       if (CRD->isLambda())
         return true;
+      if (CRD->hasDefaultConstructor() && CRD->hasAttr<DLLExportAttr>())
+          return true;
+    }
     LDC = LDC->getLexicalParent();
   }
   return false;
Index: clang/test/SemaCXX/dllexport.cpp
===================================================================
--- clang/test/SemaCXX/dllexport.cpp
+++ clang/test/SemaCXX/dllexport.cpp
@@ -1168,3 +1168,13 @@
 // expected-error@+2{{lambda cannot be declared 'dllexport'}}
 #endif
 auto Lambda = []() __declspec(dllexport) -> bool { return true; };
+
+//===----------------------------------------------------------------------===//
+// Constructor Closure with default argument
+//===----------------------------------------------------------------------===//
+template <typename>
+class __declspec(dllexport) foo {
+  foo(int x = 0);
+};
+template <>
+foo<int>::foo(int);