diff --git a/basis/unicode/breaks/breaks.factor b/basis/unicode/breaks/breaks.factor
index 9a40a8b27d..914e3f2f86 100644
--- a/basis/unicode/breaks/breaks.factor
+++ b/basis/unicode/breaks/breaks.factor
@@ -128,7 +128,7 @@ PRIVATE>
     [ first-grapheme ] >pieces ;
 
 : string-reverse ( str -- rts )
-    >graphemes reverse concat ;
+    >graphemes reverse! concat ;
 
 <PRIVATE
 
diff --git a/core/classes/classes.factor b/core/classes/classes.factor
index 3256785ecb..617ddcc331 100644
--- a/core/classes/classes.factor
+++ b/core/classes/classes.factor
@@ -102,7 +102,7 @@ M: predicate reset-word
     dup class? [ "superclass" word-prop ] [ drop f ] if ;
 
 : superclasses ( class -- supers )
-    [ superclass ] follow reverse ;
+    [ superclass ] follow reverse! ;
 
 : superclass-of? ( class superclass -- ? )
     superclasses member-eq? ;
diff --git a/core/combinators/combinators.factor b/core/combinators/combinators.factor
index 95a1b980ea..adb89767af 100644
--- a/core/combinators/combinators.factor
+++ b/core/combinators/combinators.factor
@@ -87,7 +87,7 @@ ERROR: no-cond ;
 
 : cond>quot ( assoc -- quot )
     [ dup pair? [ [ t ] swap 2array ] unless ] map
-    reverse [ no-cond ] swap alist>quot ;
+    reverse! [ no-cond ] swap alist>quot ;
 
 ! case
 ERROR: no-case object ;
diff --git a/core/splitting/splitting.factor b/core/splitting/splitting.factor
index b9b4f87b24..b3adad6bd6 100644
--- a/core/splitting/splitting.factor
+++ b/core/splitting/splitting.factor
@@ -48,7 +48,7 @@ PRIVATE>
     dupd find drop [ swap [ dup 1 + ] dip snip ] [ f ] if* ; inline
 
 : split1-last ( seq subseq -- before after )
-    [ <reversed> ] bi@ split1 [ reverse ] bi@
+    [ <reversed> ] bi@ split1 [ reverse! ] bi@
     dup [ swap ] when ;
 
 : split1-last-slice ( seq subseq -- before-slice after-slice )