diff --git a/src/proto/blob.pro b/src/proto/blob.pro
index 0b7cbd3..3adaf0f 100644
--- a/src/proto/blob.pro
+++ b/src/proto/blob.pro
@@ -14,7 +14,7 @@
 char_u *blob2string(blob_T *blob, char_u **tofree, char_u *numbuf);
 blob_T *string2blob(char_u *str);
 int blob_slice_or_index(blob_T *blob, int is_range, varnumber_T n1, varnumber_T n2, int exclusive, typval_T *rettv);
-int check_blob_index(long bloblen, varnumber_T n1, int is_range, int quiet);
+int check_blob_index(long bloblen, varnumber_T n1, int quiet);
 int check_blob_range(long bloblen, varnumber_T n1, varnumber_T n2, int quiet);
 int blob_set_range(blob_T *dest, long n1, long n2, typval_T *src);
 void blob_remove(typval_T *argvars, typval_T *rettv);