type application in quotations

[vicuna]

Original bug ID: 5080
Reporter: @glondu
Assigned to: @xclerc
Status: closed (set by @xavierleroy on 2015-12-11T18:04:46Z)
Resolution: fixed
Priority: normal
Severity: major
Version: 3.12.0+beta1 or 3.12.0+rc1
Fixed in version: 4.00.0+dev
Category: -for Camlp4 use https://github.com/ocaml/camlp4/issues
Related to: #5104
Monitored by: "Dmitry Grebeniuk" @ygrek thelema jaked jm @hcarty @Chris00

Bug description

Hello,

The following:

let test x = match x with
| <:ctyp< $a$ $b$ >> -> (a, b)

used to work with camlp4of (3.11.2), but stopped working with 3.12.0+beta1. I'm not sure if this is expected.

ocaml-batteries is affected by this issue... I've not been able to find anything else than using the expanded quotation.

[vicuna]

Comment author: jaked

I have the same problem with << $x$ -> unit >>; I get" EOI expected after [quotation of type] (in [quotation of type])". It seems to happen with leading antiquotations.

[vicuna]

Comment author: jaked

Maybe not the same bug, but as it is for <:ctyp< >> I'll put it here: for <:ctyp< $lid:id$ : mutable $t$ >> I get "illegal begin of quotation of type".

[vicuna]

Comment author: @ygrek

This affects deriving as well. First two cases can be workarounded with extra parentheses :

•  | `Function (f, t) -> <:ctyp< $expr f$ -> $expr t$ >>
  

•  | `Function (f, t) -> <:ctyp< ($expr f$ -> $expr t$) >>
  

•  | [x]   -> <:ctyp< $expr x$ $f$ >>
  

•  | x::xs -> app (<:ctyp< $expr x$ $f$ >>) xs
  

•  | [x]   -> <:ctyp< ($expr x$ $f$) >>
  

•  | x::xs -> app (<:ctyp< ($expr x$ $f$) >>) xs
  

[vicuna]

Comment author: @xclerc

The patch proposed for #5104 seems to also solve this issue.

[vicuna]

Comment author: @xclerc

Nicolas Pouillard provided me with a cleaner patch that has
been committed in "version/3.12". After some testing, it
seems to both resolve the issue and yield no regression.

Please test it, and re-open the issue if I missed something.

[vicuna]

Comment author: @damiendoligez

The current version (3.12.1+dev11) breaks lablgtk with the following error message.

File "gtkSignal.ml4", line 92, characters 10-13:
Parse error: [opt_when_expr] expected after [patt_as_patt_opt] (in [match_case0])

This happens with and without the patch that you (xclerc) provided to me in private.

[vicuna]

Comment author: @xclerc

As a first step, I reduce the bug case to:
"let f = function | `INT x -> true | _ -> false"

camlp4of no more accepts polymorphic variants with a parameter.

Investigation continues...

[vicuna]

Comment author: @xclerc

OK, my bad.
The problem stems from the dirty hack I set for #4732.