+! Type function for 'clone' had a subtle issue
+TUPLE: tuple-with-read-only-slot { x read-only } ;
+
+M: tuple-with-read-only-slot clone
+ x>> clone tuple-with-read-only-slot boa ; inline
+
+[ V{ object } ] [
+ [ { 1 2 3 } dup tuple-with-read-only-slot boa clone x>> eq? ] final-classes
+] unit-test
+
+! alien-cell outputs a simple-alien or f
+[ t ] [
+ [ { byte-array fixnum } declare alien-cell dup [ "OOPS" throw ] unless ] final-classes
+ first simple-alien class=
+] unit-test
+