genlifter: fix code generation for inline records

[let-def]

The main problem with inline records is that labels are prefixed with an absolute path, e.g.

  type t = A of { a : string; b : int }

generates code which looks like:

class virtual ['res] lifter =
  object (this)
    method lift_Test_t : Test.t -> 'res=
      (function
       | Test.A { Test.a = a; Test.b = b } ->
           this#constr "Test.t"
             ("A",
               (this#record "Test.t.A"
                  [("a", (this#string a)); ("b", (this#int b))])) : Test.t ->
                                                                    'res)
  end

which is not valid OCaml code. For inline records, labels should just be identifiers (disambiguation is based on the name of the constructor, e.g. Test.A in this example).

This patch removes the prefix at two levels:

• qualified paths in the patterns of the lifter code
• qualified paths in the parsetree produced by the lifter

The bug was found by @daacaceressa who helped testing this solution. Open question: should we backport the patch to older versions of OCaml? Because of this issue, inline records have never been supported by genlifter.

[alainfrisch]

Thanks, and sorry for the slow reaction. LGTM, only a minor inline remark.

[let-def]

@alainfrisch: Thanks for the review. I updated the diff.

[jhwoodyatt]

I believe this patch is required for supporting OCaml 4.08 (Issue #69), which adds an inline record for the Pexp_letop variant constructor.

[XVilka]

There are some conflicts that require rebase.

[XVilka]

I checked the PR - it does seem not required anymore? Because it seems it is already integrated in the master. So can be closed, I guess.