Original bug ID: 5235
Reporter: ecull78
Status: closed (set by @xavierleroy on 2011-06-04T14:40:52Z)
Resolution: not a bug
Priority: normal
Severity: minor
Version: 3.12.0
Category: ~DO NOT USE (was: OCaml general)
Monitored by: "Pascal Cuoq" "Julien Signoles"

Bug description

Empty arrays, unlike empty lists, seem to be not physically equal if compiled in the native code:

$ cat test.ml
print_endline (if [||] == [||] then "Equal!" else "Not equal!")
$ ocamlopt -o test.native test.ml
$ ./test.native
Not equal!

But when I check this in top level I have:

[||] == [||];;

• : bool = true

and even this:

(Array.create 0 0) == [||];;

• : bool = true

And using the bytecode compiler I have a similar result:

$ ocamlc -o test.byte test.ml
$ ./test.byte
Equal!

In comparison, empty lists are physically equal when using the native compiler:
$ cat test1.ml
print_endline (if [] == [] then "Equal!" else "Not equal!")
$ ocamlopt -o test1.native test1.ml
$ ./test1.native
Equal!

Additional information

tested under MacOSX 10.6.6 using a 32 bit version of ocaml compiled from sources according to the instructions