From 34b826a64dec8fd575e44ece2efba0d2cdf41311 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Tue, 18 Oct 2016 18:22:41 +0200
Subject: [PATCH] fixes #4608

---
 compiler/parampatterns.nim | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/compiler/parampatterns.nim b/compiler/parampatterns.nim
index f8f1f355cc..c51d406acc 100644
--- a/compiler/parampatterns.nim
+++ b/compiler/parampatterns.nim
@@ -230,6 +230,8 @@ proc isAssignable*(owner: PSym, n: PNode; isUnsafeAddr=false): TAssignableResult
     # builtin slice keeps lvalue-ness:
     if getMagic(n) in {mArrGet, mSlice}:
       result = isAssignable(owner, n.sons[1], isUnsafeAddr)
+    elif n.typ != nil and n.typ.kind == tyVar:
+      result = arLValue
   of nkStmtList, nkStmtListExpr:
     if n.typ != nil:
       result = isAssignable(owner, n.lastSon, isUnsafeAddr)