diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index 314c94909a..8b5db49ed2 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -808,7 +808,7 @@ proc split*(s: string, sep: string, maxsplit: int = -1): seq[string] {.noSideEff
   ##
   ## Substrings are separated by the string `sep`. This is a wrapper around the
   ## `split iterator <#split.i,string,string>`_.
-  assert(sep.len > 0)
+  doAssert(sep.len > 0)
   
   accumulateResult(split(s, sep, maxsplit))