diff --git a/core/io/files/files.factor b/core/io/files/files.factor
index 7ba3f9e82c..e96dbc8ab5 100644
--- a/core/io/files/files.factor
+++ b/core/io/files/files.factor
@@ -56,14 +56,14 @@ HOOK: (file-appender) io-backend ( path -- stream )
 : set-file-lines ( seq path encoding -- )
     [ [ print ] each ] with-file-writer ;
 
-: change-file-lines ( path encoding quot -- )
+: change-file-lines ( ..a path encoding quot: ( ..a seq -- ..b seq' ) -- ..b )
     [ [ file-lines ] dip call ]
     [ drop set-file-lines ] 3bi ; inline
 
 : set-file-contents ( seq path encoding -- )
     [ write ] with-file-writer ;
 
-: change-file-contents ( path encoding quot -- )
+: change-file-contents ( ..a path encoding quot: ( ..a seq -- ..b seq' ) -- ..b )
     [ [ file-contents ] dip call ]
     [ drop set-file-contents ] 3bi ; inline