From bfca977d5fc2f38c04edef2647ef01c80a810c23 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Tue, 2 Jul 2013 19:44:40 +0200
Subject: [PATCH] fixes #505

---
 compiler/semexprs.nim | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index ff68d6b8e0..57457c1013 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -750,8 +750,11 @@ proc semEcho(c: PContext, n: PNode): PNode =
   checkMinSonsLen(n, 1)
   for i in countup(1, sonsLen(n) - 1): 
     var arg = semExprWithType(c, n.sons[i])
-    n.sons[i] = semExpr(c, buildStringify(c, arg))
-  
+    n.sons[i] = semExprWithType(c, buildStringify(c, arg))
+    let t = n.sons[i].typ
+    if t == nil or t.skipTypes(abstractInst).kind != tyString:  
+      LocalError(n.info, errGenerated,
+                 "implicitly invoked '$' does not return string")
   let t = n.sons[0].typ
   if tfNoSideEffect notin t.flags: incl(c.p.owner.flags, sfSideEffect)
   result = n