diff --git a/src/io/csv_file.f90 b/src/io/csv_file.f90
index 16cfb98e80e..972dfe2bd55 100644
--- a/src/io/csv_file.f90
+++ b/src/io/csv_file.f90
@@ -310,9 +310,9 @@ function csv_file_count_lines(this) result(n)
 
     call this%check_exists()
 
-    open(file = trim(f%fname), status = 'old', newunit = file_unit, &
+    open(file = trim(this%fname), status = 'old', newunit = file_unit, &
          iostat = ierr)
-    if (ierr .ne. 0) call neko_error("Error while opening " // trim(f%fname))
+    if (ierr .ne. 0) call neko_error("Error while opening " // trim(this%fname))
 
     n = 0