F* does not build with sedlex 2.4

[tahina-pro]

Yesterday, sedlex 2.4 was released on the opam package repository. With that new version of sedlex, I tried to build F* master, but I failed. When doing make, here is what I got:

make -C src/ocaml-output
make[1]: Entering directory '/home/everest/FStar/src/ocaml-output'
...
[OCAMLBUILD]
cd ../../ && ocamlbuild -cflag -g -I src/ocaml-output -I src/basic/ml -I src/parser/ml -I src/fstar/ml -I src/extraction/ml -I src/prettyprint/ml -I src/tactics/ml -I src/tests/ml -I ulib/ml -j 4 -build-dir src/ocaml-output/_build -use-ocamlfind main.native FStar_Syntax_Syntax.inferred.mli
+ ocamlfind ocamlc -c -g -thread -package stdint -package compiler-libs -package compiler-libs.common -package menhirLib -package dynlink -package pprint -package sedlex -package yojson -package ppxlib -package process -package sedlex.ppx -package batteries -package zarith -package ppx_deriving.std -package ppx_deriving_yojson -I src/parser/ml -I ulib/ml -I src/ocaml-output -I src/tests/ml -I src/basic/ml -I src/tactics/ml -I src/extraction/ml -I src/fstar/ml -I src/prettyprint/ml -o src/parser/ml/FStar_Parser_LexFStar.cmo src/parser/ml/FStar_Parser_LexFStar.ml
File "_none_", line 1:
Error: Unbound value Sedlexing.__private__next_int
Command exited with code 2.
Compilation unsuccessful after building 113 targets (112 cached) in 00:00:01.
make[1]: *** [Makefile:119: _build/src/fstar/ml/main.native] Error 10
make[1]: Leaving directory '/home/everest/FStar/src/ocaml-output'
make: *** [Makefile:6: all] Error 2

Due to that failure, the people who released sedlex 2.4 had to put a sedlex < 2.4 upper bound on the dependencies for the fstar opam package (ocaml/opam-repository@915bcf6); and I had to pin sedlex to 2.3 on Project Everest for ./everest opam (project-everest/everest@7440073).

[toots]

Hi! As fas as I can tell, sedlex 2.4 has a clean mli interface. This issue is most likely due to a competing mli interface being declared somewhere in the project build tree that is throwing the compiler off.

[toots]

Just debugged a similar issue here: ocaml/opam-repository#19561 (comment) Here's the final comment:

This issue is due to an embedded mli of the module shipped with the projet that prevents it from linking with the new API: https://github.com/frenetic-lang/frenetic/blob/master/src/lib/netkat/Lexer.cppo.ml#L13

I believe that the missing functionalities for tracking source locations were added into Sedlex a while ago. I'd suggest to either update to a recent version or rename the custom module so that the names do not clash.