diff --git a/compiler/astalgo.nim b/compiler/astalgo.nim
index cfa1a67fdb..0efa096be5 100644
--- a/compiler/astalgo.nim
+++ b/compiler/astalgo.nim
@@ -194,6 +194,7 @@ proc sameIgnoreBacktickGensymInfo(a, b: string): bool =
   if a[0] != b[0]: return false
   var last = a.len - 1
   while last > 0 and a[last] != '`': dec(last)
+  if last == 0: last = a.len - 1
 
   var i = 1
   var j = 1