From e92ccff57a81bb5274d5736ede910d3d989275c4 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Thu, 4 Aug 2016 01:29:49 +0200
Subject: [PATCH] fixes #4550

---
 compiler/semtypes.nim | 1 +
 1 file changed, 1 insertion(+)

diff --git a/compiler/semtypes.nim b/compiler/semtypes.nim
index a529e80c08..9d00c06caf 100644
--- a/compiler/semtypes.nim
+++ b/compiler/semtypes.nim
@@ -393,6 +393,7 @@ proc semTuple(c: PContext, n: PNode, prev: PType): PType =
         addSon(result.n, newSymNode(field))
         addSonSkipIntLit(result, typ)
       if gCmd == cmdPretty: styleCheckDef(a.sons[j].info, field)
+  if result.n.len == 0: result.n = nil
 
 proc semIdentVis(c: PContext, kind: TSymKind, n: PNode,
                  allowed: TSymFlags): PSym =