Merge pull request #1244 from AndrejMitrovic/Fix7666

Issue 7666 - Implement function to reverse fields of a tuple.

std/typecons.d

@@ -551,6 +551,21 @@ assert(s[0] == "abc" && s[1] == 4.5);
         return *cast(typeof(return) *) &(field[from]);
     }
 
+/**
+   Return a copy of this Tuple with its fields in reverse order.
+ */
+    @property
+    auto reversed()
+    {
+        static if (is(typeof(this) : Tuple!A, A...))
+            alias RevTypes = Reverse!A;
+
+        Tuple!RevTypes result;
+        auto tup = this.tupleof;
+        result.tupleof = Reverse!tup;
+        return result;
+    }
+
 /**
    The length of the tuple.
  */
@@ -739,6 +754,13 @@ unittest
         alias Tuple!(const(int)) T;
         auto t2 = T(1);
     }
+    // 7666
+    {
+        auto tup = tuple(1, "2");
+        assert(tup.reversed == tuple("2", 1));
+        auto tup2 = tuple(1);
+        assert(tup2.reversed == tuple(1));
+    }
 }
 unittest
 {