diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index 082f02c07b..51694e6ade 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -331,7 +331,7 @@ proc isNilOrEmpty*(s: string): bool {.noSideEffect, procvar, rtl, extern: "nsuIs
   ## Checks if `s` is nil or empty.
   result = len(s) == 0
 
-proc isNilOrWhitespace*(s: string): bool {.noSideEffect, procvar, rtl, extern: "nsuIsNilOrWhitespace".} = isSpace(s)
+proc isNilOrWhitespace*(s: string): bool {.noSideEffect, procvar, rtl, extern: "nsuIsNilOrWhitespace".} =
   ## Checks if `s` is nil or consists entirely of whitespace characters.
   ##
   ## This is an alias to `isSpace`.