diff --git a/wrap/FileWriter.cpp b/wrap/FileWriter.cpp
index 2c3843b37..c07de0eb0 100644
--- a/wrap/FileWriter.cpp
+++ b/wrap/FileWriter.cpp
@@ -29,7 +29,7 @@ void FileWriter::emit(bool add_header, bool force_overwrite) const {
   bool file_exists = true;
   try {
     existing_contents = file_contents(filename_.c_str(), add_header);
-  } catch (const CantOpenFile& e) {
+  } catch (const CantOpenFile& ) {
     file_exists = false;
   }