diff --git a/plab/flatten/function.go b/plab/flatten/function.go
index e04e12010a84c92ac29a62988894d6995ee96602..8deb0b152e19af490b674b237402e991dea4f759 100644
--- a/plab/flatten/function.go
+++ b/plab/flatten/function.go
@@ -65,6 +65,10 @@ func InlineAllFuncs(str string) (string, error) {
 				argStop++
 			}
 
+			if argsStart == argStop {
+				argStop++
+			}
+
 			inlined := f.Inline(args...)
 			soFar.WriteString("\n")
 			soFar.WriteString(inlined)