--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp0x/abstract-default1.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,26 @@
+// PR c++/83796
+// { dg-do compile { target c++11 } }
+
+struct MyAbstractClass
+{
+  virtual int foo() const = 0;
+};
+
+struct TestClass
+{
+  TestClass(const MyAbstractClass& m = {})  // { dg-error "abstract type" }
+  : value_(m.foo()) {}
+
+  int value_;
+};
+
+int TestFunction(const MyAbstractClass& m = {})  // { dg-error "abstract type" }
+{
+  return m.foo();
+}
+
+int main()
+{
+  TestClass testInstance;  // { dg-error "abstract type" }
+  TestFunction();  // { dg-error "abstract type" }
+}