OCaml 4.11 support

[kit-ty-kate]

Port work from @rwmjones. See https://github.com/ocaml-ppx/ppx_tools/issues/81

Here two points I'm not so sure about:

• I'm not sure what is the constant method. The original commit had a (* XXX? *) comment there.
• I'm not sure what to use instead of the deprecated Longident.parse x as the proposed Parse.longident (Lexing.from_string x) does not work and fails to parse several things. @octachron any idea?

[kit-ty-kate]

By ~weird error message~fails to parse several things, I meant mainly:

File "dumpast.ml", line 35, characters 12-33:
35 |     inherit [_] Ast_lifter.lifter as super
                 ^^^^^^^^^^^^^^^^^^^^^
Error: Unbound class Ast_lifter.lifter

It seems that somewhere it tries to parse [_] Ast_lifter.lifter, and only Longident.parse is able to parse this successfully.

[rwmjones]

I'm afraid I don't know the answer to any of these questions either :-(

[Octachron]

I will have a look, but the argument of inherit is a class expression, trying to parse it as a Longident is bound to fail.

[Octachron]

The source of the error is in fact the cons functions in ast_convenience that are using the internal name "::" for the constructor (::).

[gasche]

Who has commit rights here and can decide to merge this PR or a similar PR? I don't, and I don't actually know who does. (cc @Drup who I believe did merge a PR a while back.)

[kit-ty-kate]

I have, I'll make a release soon. I just wanted to deal with packages that depend on ppx_tools first

[kit-ty-kate]

All good now. Sorry for the delay