diff --git a/lib/system.nim b/lib/system.nim
index 13d0b4746e..79c014a7c1 100755
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -719,7 +719,7 @@ proc insert*[T](x: var seq[T], item: T, i = 0) {.noSideEffect.} =
   var j = xl-1
   while j >= i:
     x[j+1] = x[j]
-    inc(j)
+    dec(j)
   x[i] = item