Antiquotation bug (quotation expr, with antiquotation list) (Mantis 5685)

[damiendoligez]

Transferred from http://caml.inria.fr/mantis/view.php?id=5685
This is the original bug report, but see the Mantis page for the discussion and patch.

value f x = <:expr< $list:x$ >> ;
will be accepted and the type is weird
list Ast.ident -> Ast.expr (This absolutely not what I want)
The problem comes from that in the parser entry
expr accept TRY val_longident which accept ANTIQUOT, and the context is changed.
I guess there maybe other similar bugs in other places. The patch is attached, plz review the patch. Thanks
Another problem, I added some tracing functionality for the parser in my in-home camlp4 which helps me a lot to pinpoint the problem. How about the idea to add some tracing for the parser?