diff --git a/src/nimgen/external.nim b/src/nimgen/external.nim
index 571c7e0..5abc1c6 100644
--- a/src/nimgen/external.nim
+++ b/src/nimgen/external.nim
@@ -111,7 +111,7 @@ proc runPreprocess*(file, ppflags, flags: string, inline: bool): string =
 
   # Include content only from file
   var
-    rdata: Rope
+    rdata = rope("")
     start = false
     sfile = file.sanitizePath