fix for template redefinition. test cases added.

tests/run/toverl2.nim

@@ -1,6 +1,6 @@
 discard """
   file: "toverl2.nim"
-  output: "true012"
+  output: "true012innertrue"
 """
 # Test new overloading resolution rules
 
@@ -14,14 +14,20 @@ iterator toverl2(x: int): int =
   while res < x: 
     yield res
     inc(res)
-    
+
 var
   pp: proc (x: bool): string = toverl2
+
 stdout.write(pp(true))
+
 for x in toverl2(3): 
   stdout.write(toverl2(x))
+
+block:
+  proc toverl2(x: int): string = return "inner"
+  stdout.write(toverl2(5))
+  stdout.write(true)
+
 stdout.write("\n")
-#OUT true012
-
-
+#OUT true012innertrue