diff --git a/gcc/coretypes.h b/gcc/coretypes.h
index 720f9f9c63f..6b6cfcdf210 100644
--- a/gcc/coretypes.h
+++ b/gcc/coretypes.h
@@ -359,10 +359,6 @@ struct kv_pair
   const ValueType value;	/* the value of the name */
 };
 
-/* Alias of the first type, ignoring the second.  */
-template<typename T1, typename T2>
-using first_type = T1;
-
 /* Iterator pair used for a collection iteration with range-based loops.  */
 
 template<typename T>
diff --git a/gcc/recog.h b/gcc/recog.h
index d674d384723..3e4b55bdf3f 100644
--- a/gcc/recog.h
+++ b/gcc/recog.h
@@ -297,7 +297,7 @@ struct insn_gen_fn
   template<typename ...Ts>
   rtx_insn *operator() (Ts... args) const
   {
-    typedef rtx_insn *(*funcptr) (first_type<rtx, Ts>...);
+    typedef rtx_insn *(*funcptr) (decltype ((void) args, NULL_RTX)...);
     return ((funcptr) func) (args...);
   }