diff --git a/src/clos/streams.lsp b/src/clos/streams.lsp
index 5b6c5e8d0..4329b121f 100644
--- a/src/clos/streams.lsp
+++ b/src/clos/streams.lsp
@@ -203,7 +203,7 @@
   (:documentation
    "This is like CL:FILE-POSITION, but for Gray streams."))
 
-(defgeneric stream-file-length (stream &optional position)
+(defgeneric stream-file-length (stream)
   (:documentation
    "This is like CL:FILE-LENGTH, but for Gray streams."))