fixes yet another regression

tests/closure/tnoclosure.nim

@@ -0,0 +1,25 @@
+discard """
+  output: '''@[1]
+@[1, 1]
+@[1, 2, 1]
+@[1, 3, 3, 1]
+@[1, 4, 6, 4, 1]
+@[1, 5, 10, 10, 5, 1]
+@[1, 6, 15, 20, 15, 6, 1]
+@[1, 7, 21, 35, 35, 21, 7, 1]
+@[1, 8, 28, 56, 70, 56, 28, 8, 1]
+@[1, 9, 36, 84, 126, 126, 84, 36, 9, 1]'''
+"""
+
+import sequtils
+
+proc pascal(n: int) =
+  var row = @[1]
+  for r in 1..n:
+    echo row
+    row = zip(row & @[0], @[0] & row).mapIt(it[0] + it[1])
+
+pascal(10)
+
+# bug #3499 last snippet fixed
+# bug 705  last snippet fixed