From 31d4f30a4965a0806317909bd84beabbd7bc327c Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Fri, 21 Sep 2018 06:23:59 +0200
Subject: [PATCH] functional.forward: Fix template visibility bug

Because of the private template forwardOne, forward couldn't be used in
other modules. forwardOne cannot be a local template either since it
accepts an alias as its template parameter.
---
 source/tanya/functional.d | 43 +++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/source/tanya/functional.d b/source/tanya/functional.d
index 3b5adf5..f628a51 100644
--- a/source/tanya/functional.d
+++ b/source/tanya/functional.d
@@ -17,21 +17,6 @@ module tanya.functional;
 import tanya.algorithm.mutation;
 import tanya.meta.metafunction;
 
-private template forwardOne(alias arg)
-{
-    static if (__traits(isRef, arg) || __traits(isOut, arg))
-    {
-        alias forwardOne = arg;
-    }
-    else
-    {
-        @property auto forwardOne()
-        {
-            return move(arg);
-        }
-    }
-}
-
 /**
  * Forwards its argument list preserving $(D_KEYWORD ref) and $(D_KEYWORD out)
  * storage classes.
@@ -47,13 +32,35 @@ private template forwardOne(alias arg)
  */
 template forward(args...)
 {
-    static if (args.length == 1)
+    static if (args.length == 0)
     {
-        alias forward = forwardOne!(args[0]);
+        alias forward = AliasSeq!();
+    }
+    else static if (__traits(isRef, args[0]) || __traits(isOut, args[0]))
+    {
+        static if (args.length == 1)
+        {
+            alias forward = args[0];
+        }
+        else
+        {
+            alias forward = AliasSeq!(args[0], forward!(args[1 .. $]));
+        }
     }
     else
     {
-        alias forward = Map!(forwardOne, args);
+        @property auto forwardOne()
+        {
+            return move(args[0]);
+        }
+        static if (args.length == 1)
+        {
+            alias forward = forwardOne;
+        }
+        else
+        {
+            alias forward = AliasSeq!(forwardOne, forward!(args[1 .. $]));
+        }
     }
 }