--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/warn/Wmismatched-tags-5.C	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,117 @@
+/* PR c++/93810 - missing -Wmismatched-tags and -Wredundant-tags on a typedef
+   of an implicit class template specialization
+  { dg-do compile }
+  { dg-options "-Wall -Wmismatched-tags" }
+  { dg-require-effective-target c++11 } */
+
+class A;                                // { dg-message "declared as 'class'" }
+typedef        A A0;
+typedef class  A A0;
+typedef struct A A0;                    // { dg-warning "-Wmismatched-tags" }
+
+template <int> struct B;                // { dg-message "declared as 'struct'" }
+typedef        B<0> B0;
+typedef class  B<0> B0;                 // { dg-warning "-Wmismatched-tags" }
+typedef struct B<0> B0;
+
+
+// Exercise member types of templates with non-type arguments.
+template <int> struct CN;               // { dg-message "declared as 'struct'" }
+
+template <int N>
+struct X_CNp1 {
+  typedef CN<N + 1> CNp1;
+};
+
+template <int N>
+struct X_class_CNp1 {
+  typedef class CN<N + 1> CNp1;         // { dg-warning "-Wmismatched-tags" }
+};
+
+template <int N>
+struct X_struct_CNp1 {
+  typedef struct CN<N + 1> CNp1;
+};
+
+
+// Exercise partial specialization of templates with member types.
+template <class> class CT1;
+template <class T> struct CT1<T*> { };
+template <class T> struct CT1<T**> { };
+template <class T> class  CT1<T***> { };
+
+template <class> struct CT2;
+template <class T> struct CT2<T*> {
+  // Expect class-key to match the primary.
+         CT1<T> ct1_0;
+  class  CT1<T> ct1_1;
+  struct CT1<T> ct1_2;                  // { dg-warning "-Wmismatched-tags" }
+
+  // Expect class-key to match the CT1<T*> partial specialization.
+         CT1<T*> ct1p1_0;
+  class  CT1<T*> ct1p1_1;               // { dg-warning "-Wmismatched-tags" }
+  struct CT1<T*> ct1p1_2;
+
+  // Expect class-key to match the CT1<T**> partial specialization.
+         CT1<T**> ct1p2_0;
+  class  CT1<T**> ct1p2_1;              // { dg-warning "-Wmismatched-tags" }
+  struct CT1<T**> ct1p2_2;
+
+  // Expect class-key to match the CT1<T***> partial specialization.
+         CT1<T***> ct1p3_0;
+  class  CT1<T***> ct1p3_1;
+  struct CT1<T***> ct1p3_2;             // { dg-warning "-Wmismatched-tags" }
+
+  // Expect class-key to still match the CT1<T***> partial specialization.
+         CT1<T****> ct1p4_0;
+  class  CT1<T****> ct1p4_1;
+  struct CT1<T****> ct1p4_2;            // { dg-warning "-Wmismatched-tags" }
+};
+
+// Exercise many partial specializations (since the class-key for each
+// must be tracked separately from the others).
+template <class>   class  D;
+template <class T> struct D<T*>;
+template <class T> class  D<T&>;
+template <class T> struct D<const T*>;
+template <class T> class  D<const T&>;
+template <class T> struct D<volatile T*>;
+template <class T> class  D<volatile T&>;
+template <class T> struct D<const volatile T*>;
+template <class T> class  D<const volatile T&>;
+
+typedef class  D<int*> DIP;             // { dg-warning "-Wmismatched-tags" }
+typedef struct D<int*> DIP;
+typedef class  D<int*> DIP;             // { dg-warning "-Wmismatched-tags" }
+typedef struct D<int*> DIP;
+
+typedef class  D<int&>  DIR;
+typedef struct D<int&> DIR;             // { dg-warning "-Wmismatched-tags" }
+typedef class  D<int&>  DIR;
+
+
+typedef struct D<const int*> DCIP;
+typedef class  D<const int*> DCIP;      // { dg-warning "-Wmismatched-tags" }
+typedef struct D<const int*> DCIP;
+
+typedef struct D<const int&> DCIR;      // { dg-warning "-Wmismatched-tags" }
+typedef class  D<const int&>  DCIR;
+typedef struct D<const int&> DCIR;      // { dg-warning "-Wmismatched-tags" }
+
+
+typedef struct D<volatile int*> DVIP;
+typedef class  D<volatile int*> DVIP;   // { dg-warning "-Wmismatched-tags" }
+typedef struct D<volatile int*> DVIP;
+
+typedef struct D<volatile int&> DVIR;   // { dg-warning "-Wmismatched-tags" }
+typedef class  D<volatile int&> DVIR;
+typedef struct D<volatile int&> DVIR;   // { dg-warning "-Wmismatched-tags" }
+
+
+typedef struct D<const volatile int*> DCVIP;
+typedef class  D<const volatile int*> DCVIP;    // { dg-warning "-Wmismatched-tags" }
+typedef struct D<const volatile int*> DCVIP;
+
+typedef struct D<const volatile int&> DCVIR;    // { dg-warning "-Wmismatched-tags" }
+typedef class  D<const volatile int&> DCVIR;
+typedef struct D<const volatile int&> DCVIR;    // { dg-warning "-Wmismatched-tags" }