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Here is the latest OCaml Weekly News, for the week of June 27 to July 04, 2017.

  1. OCaml version 4.05.0+rc1
  2. Intel Skylake / Kaby Lake hardware bug affects OCaml programs
  3. From the OCaml discourse
  4. Ocaml Github Pull Requests
  5. Other OCaml News

OCaml version 4.05.0+rc1


Damien Doligez announced:
The release of OCaml version 4.05.0 is imminent.  We have
created a release candidate for your testing pleasure.  Please
test your favourite software with it.  Then let me know whether
it works for you.

We want to know about any show-stopping bugs, especially in the
compilation and installation phases.

This release candidate is available as source code at this
address: < >

It is also available as an OPAM switch: 4.05.0+rc1

Happy hacking,

-- Damien Doligez for the OCaml team.

OCaml 4.05.0 :

(Changes that can break existing programs are marked with a "*")

### Language features:

### Code generation and optimizations:

- MPR#7201, GPR#954: Correct wrong optimisation of "0 / <expr>"
  and "0 mod <expr>" in the case when <expr> was a non-constant
  evaluating to zero
  (Mark Shinwell)

- MPR#7357, GPR#832: Improve compilation time for toplevel
  include(struct ... end : sig ... end)
  (Alain Frisch, report by Hongbo Zhang, review by Jacques Garrigue)

- GPR#504: Instrumentation support for fuzzing with afl-fuzz.
  (Stephen Dolan, review by Alain Frisch, Pierre Chambart, Mark
  Shinwell, Gabriel Scherer and Damien Doligez)

- GPR#863, GPR#1068, GPR#1069: Optimise matches with constant
  results to lookup tables.
  (Stephen Dolan, review by Gabriel Scherer, Pierre Chambart,
  Mark Shinwell, and bug report by Gabriel Scherer)

- GPR#1150: Fix typo in arm64 assembler directives
  (KC Sivaramakrishnan)

- PR#7533, GPR#1173: Correctly perform side effects for certain
  cases of "/" and "mod"
  (Mark Shinwell, report by Jan Mitgaard)

### Runtime system:

- MPR#385, GPR#953: Add caml_startup_exn
  (Mark Shinwell)

- PR#7423, GPR#946: expose new exception-raising functions
  `void caml_{failwith,invalid_argument}_value(value msg)`
  in addition to
  `void caml_{failwith,invalid_argument}(char const *msg)`.
  The previous functions would not free their message argument, so
  were inconvient for dynamically-allocated messages; the messages
  passed to the new functions are handled by the garbage collector.
  (Gabriel Scherer, review by Mark Shinwell, request by Immanuel Litzroth)

- PR#7557, GPR#1213: More security for getenv
  (Damien Doligez, reports by Seth Arnold and Eric Milliken, review by
  Xavier Leroy, David Allsopp, Stephen Dolan, Hannes Mehnert)

- GPR#795: remove 256-character limitation on Sys.executable_name
  (Xavier Leroy)

- GPR#891: Use -fno-builtin-memcmp when building runtime with gcc.
  (Leo White)

### Type system:

- PR#6608, GPR#901: unify record types when overriding all fields
  (Tadeu Zagallo and Gabriel Scherer, report by Jeremy Yallop,
  review by David Allsopp, Jacques Garrigue)

* PR#7414, GPR#929: Soundness bug with non-generalized type variables and
  (Jacques Garrigue, report by Leo White)

### Compiler user-interface and warnings:

- PR#7050, GPR#748 GPR#843 GPR#864: new `-args/-args0 <file>` parameters to
  provide extra command-line arguments in a file -- see documentation.
  User programs may implement similar options using the new `Expand`
  constructor of the `Arg` module.
  (Bernhard Schommer, review by Jérémie Dimino, Gabriel Scherer
   and Damien Doligez, discussion with Alain Frisch and Xavier Leroy,
   feature request from the Coq team)

- PR#7137, GPR#960: "-open" command line flag now accepts a module path
  (not a module name) (Arseniy Alekseyev and Leo White)

- PR#7172, GPR#970: add extra (ocamlc -config) options
  int_size, word_size, ext_exe
  (Gabriel Scherer, request by Daniel Bünzli)

- PR#7315, GPR#736: refine some error locations
  (Gabriel Scherer and Alain Frisch, report by Matej Košík)

- PR#7473, GPR#1025: perform proper globbing for command-line arguments on
  (Jonathan Protzenko)

- PR#7479: make sure "ocamlc -pack" is only given .cmo and .cmi files,
  and that "ocamlopt -pack" is only given .cmx and .cmi files.
  (Xavier Leroy)

- GPR#796: allow compiler plugins to declare their own arguments.
  (Fabrice Le Fessant)

- GPR#829: better error when opening a module aliased to a functor
  (Alain Frisch)

- GPR#911: ocamlc/ocamlopt do not pass warnings-related options to C
  compiler when called to compile third-party C source files
  (Sébastien Hinderer)

- GPR#915: fix -dsource ( bugs
  (Runhang Li, review by Alain Frisch)

* GPR#933: ocamlopt -p now reports an error on platforms that do not
  support profiling with gprof; dummy profiling libraries are no longer
  installed on such platforms.
  This can be tested with ocamlopt -config
  (Sébastien Hinderer)

- GPR#1009: "ocamlc -c -linkall" and "ocamlopt -c -linkall" can now be used
  to set the "always link" flag on individual compilation units.  This
  controls linking with finer granularity than "-a -linkall", which sets
  the "always link" flag on all units of the given library.
  (Xavier Leroy)

- GPR#1015: add option "-plugin PLUGIN" to ocamldep too. Use compilerlibs
  to build ocamldep.
  (Fabrice Le Fessant)

- GPR#1027: various improvements to -dtimings, mostly including time
  spent in subprocesses like preprocessors
  (Valentin Gatien-Baron, review by Gabriel Scherer)

- GPR#1098: the compiler now takes the boolean "OCAML_COLOR" environment
  variable into account if "-color" is not provided.  This allows users
  to override the default behaviour without modifying invocations of ocaml
  (Hannes Mehnert, Guillaume Bury,
   review by Daniel Bünzli, Gabriel Scherer, Damien Doligez)

### Standard library:

- PR#6975, GPR#902: Truncate function added to stdlib Buffer module
  (Dhruv Makwana, review by Alain Frisch and Gabriel Scherer)

- PR#7279 GPR#710: `Weak.get_copy` `Ephemeron.*_copy` doesn't copy
  custom blocks anymore
  (François Bobot, Alain Frisch, bug reported by Martin R. Neuhäußer,
  review by Thomas Braibant and Damien Doligez)

* PR#7500, GPR#1081: Remove Uchar.dump
  (Daniel Bünzli)

- GPR#760: Add a functions List.compare_lengths and
  List.compare_length_with to avoid full list length computations
  (Fabrice Le Fessant)

- GPR#778: Arg: added option Expand that allows to expand a string
  argument to a string array of new arguments
  (Bernhard Schommer)

- GPR#849: Exposed Spacetime.enabled value
  (Leo White)

- GPR#885: Option-returning variants of stdlib functions
  (Alain Frisch, review by David Allsopp and Bart Jacobs)

- GPR#869: Add find_first, find_first_opt, find_last, find_last_opt to
  maps and sets.  Find the first or last binding or element
  satisfying a monotonic predicate.
  (Gabriel de Perthuis, with contributions from Alain Frisch, review by
  Hezekiah M. Carty and Simon Cruanes, initial report by Gerd Stolpmann)

- GPR#875: Add missing functions to ArrayLabels, BytesLabels,
  ListLabels, MoreLabels, StringLabels so they are compatible with
  non-labeled counterparts.
  (Roma Sokolov)

- GPR#999: Arg, do not repeat thrice usage_msg when reporting an error
  (Florian Angeletti, review by Gabriel Scherer)

- GPR#1042: Fix escaping of command-line arguments in
  Unix.create_process{,_env} under Windows.  Arguments with tabs should now
  be received verbatim by the child process.
  (Nicolas Ojeda Bar, Andreas Hauptmann review by Xavier Leroy)

### Debugging and profiling:

- PR#7258: ocamldebug's "install_printer" command had problems with
  module aliases
  (Xavier Leroy)

- GPR#378: Add [Printexc.raise_with_backtrace] to raise an exception using
  an explicit backtrace
  (François Bobot, review by Gabriel Scherer, Xavier Leroy, Damien Doligez,
   Frédéric Bour)

### Manual and documentation:

- PR#6597, GPR#1030: add forward references to language extensions
  that extend non-terminal symbols in the language reference section.
  (Florian Angeletti, review by Gabriel Scherer)

- PR#7497, GPR#1095: manual, enable numbering for table of contents
  (Florian Angeletti, request by Daniel Bünzli)

- PR#7539, GPR#1181: manual, update dead links in ocamldoc chapter
  (Florian Angeletti)

- GPR#633: manpage and manual documentation for the `-opaque` option
  (Konstantin Romanov, Gabriel Scherer, review by Mark Shinwell)

- GPR#916: new tool lintapidiff, use it to update the manual with
  @since annotations for API changes introduced between 4.00-4.05.
  (Edwin Török, review by Gabriel Scherer, discussion with Alain Frisch,
   David Allsopp, Sébastien Hinderer, Damien Doligez and Xavier Leroy)

- GPR#939: activate the caml_example environment in the language
  extensions section of the manual. Convert some existing code
  examples to this format.
  (Florian Angeletti)

- GPR#1082: clarify that the use of quoted string for preprocessed
  foreign quotations still requires the use of an extension node
  [%foo ...] to mark non-standard interpretation.
  (Gabriel Scherer, request by Matthew Wahab in GPR#1066,
   review by Florian Angeletti)

- add a HACKING.adoc file to contain various tips and tricks for
  people hacking on the repository. See also for
  advice on sending contributions upstream.
  (Gabriel Scherer and Gabriel Radanne, review by David Allsopp,
  inspired by John Whitington)

### Other libraries:

- PR#7158: Event.sync, Mutex.create, Condition.create cause too many GCs.
  The fix is to no longer consider mutexes and condition variables
  as rare kernel resources.
  (Xavier Leroy)

- PR#7264: document the different behaviors of Unix.lockf under POSIX
  and under Win32.
  (Xavier Leroy, report by David Allsopp)

- MPR#7339, GPR#787: Support the '0 dimension' case for bigarrays
  (see Bigarray documentation)
  (Laurent Mazare,
   review by Gabriel Scherer, Alain Frisch and Hezekiah M. Carty)

* PR#7342, GPR#797: fix on pipes with no data left on Windows
  it previously raised an EPIPE error, it now returns 0 like other OSes
  (Jonathan Protzenko)

- GPR#650: in the Unix library, add `?cloexec:bool` optional arguments to
  functions that create file descriptors (`dup`, `dup2`, `pipe`, `socket`,
  `socketpair`, `accept`).  Implement these optional arguments in the
  most atomic manner provided by the operating system to set (or clear)
  the close-on-exec flag at the same time the file descriptor is created,
  reducing the risk of race conditions with `exec` or `create_process`
  calls running in other threads, and improving security.  Also: add a
  `O_KEEPEXEC` flag for `openfile` by symmetry with `O_CLOEXEC`.
  (Xavier Leroy)

- GPR#996: correctly update caml_top_of_stack in systhreads
  (Fabrice Le Fessant)

### Toplevel:

- PR#7060, GPR#1035: Print exceptions in installed custom printers
  (Tadeu Zagallo, review by David Allsopp)

### Tools:

- PR#5163: ocamlobjinfo, dump globals defined by bytecode executables
  (Stéphane Glondu)

- PR#7333: ocamldoc, use the first sentence of text file as
  a short description in overviews.
  (Florian Angeletti)

- GPR#848: ocamldoc, escape link targets in HTML output
  (Etienne Millon, review by Gabriel Scherer, Florian Angeletti and
  Daniel Bünzli)

- GPR#986: ocamldoc, use relative paths in error message
  to solve ocamlbuild+doc usability issue (ocaml/ocamlbuild#79)
  (Gabriel Scherer, review by Florian Angeletti, discussion with Daniel Bünzli)

- GPR#1017: ocamldoc, add an option to detect code fragments that could be
  transformed into a cross-reference to a known element.
  (Florian Angeletti, review and suggestion by David Allsopp)

- clarify ocamldoc text parsing error messages
  (Gabriel Scherer)

### Compiler distribution build system:

- PR#7377: remove -std=gnu99 for newer gcc versions
  (Damien Doligez, report by ygrek)

- GPR#693: fail on unexpected errors or warnings within caml_example
  (Florian Angeletti)

- GPR#803: new ocamllex-based tool to extract bytecode compiler
  opcode information from C headers.
  (Nicolas Ojeda Bar)

- GPR#827: install missing mli and cmti files, new make target
  install-compiler-sources for installation of compiler-libs ml files
  (Hendrik Tews)

- GPR#887: allow -with-frame-pointers if clang is used as compiler on Linux
  (Bernhard Schommer)

- GPR#898: fix locale-dependence of primitive list order,
  detected through
  (Hannes Mehnert, review by Gabriel Scherer and Ximin Luo)

- GPR#907: Remove unused variable from the build system
  (Sébastien Hinderer, review by whitequark, Gabriel Scherer, Adrien Nader)

- GPR#911: Clarify the use of C compiler related variables in the build system.
  (Sébastien Hinderer, review by Adrien Nader, Alain Frisch, David Allsopp)

- GPR#919: use clang as preprocessor assembler if clang is used as compiler
  (Bernhard Schommer)

- GPR#927: improve the detection of hashbang support in the configure script
  (Armaël Guéneau)

- GPR#932: install ocaml{c,lex}->ocaml{c,lex}.byte symlink correctly
  when the opt target is built but opt.opt target is not.

- GPR#935: allow build in Android's termux
  (ygrek, review by Gabriel Scherer)

- GPR#984: Fix compilation of compiler distribution when Spacetime
  (Mark Shinwell)

- GPR#991: On Windows, fix installation when native compiler is not
  (Sébastien Hinderer, review by David Allsopp)

- GPR#1033: merge Unix and Windows build systems in the root directory
  (Sébastien Hinderer, review by Damien Doligez and Adrien Nader)

- GPR#1047: Make .depend files generated for C sources more portable
  (Sébastien Hinderer, review by Xavier Leroy and David Allsopp)

- GPR#1076: Simplify ocamlyacc's build system
  (Sébastien Hinderer, review by David Allsopp)

### Compiler distribution build system: Makefile factorization

The compiler distribution build system (the set of Makefiles used to
build the compiler distribution) traditionally had separate Makefiles
for Unix and Windows, which lead to some amount of duplication and
subtle differences and technical debt in general -- for people working
on the compiler distribution, but also cross-compilation or porting to
new systems. During the 4.05 development period, Sébastien Hinderer
worked on harmonizing the build rules and merging the two build

* Some changes were made to the config/Makefile file which
  is exported as $(ocamlc -where)/Makefile.config, and on
  which some advanced users might rely. The changes are
  as follows:
  - a BYTERUN variable was added that points to the installed ocamlrun
  - the PARTIALLD variable was removed (PACKLD is more complete)
  - the always-empty DLLCCCOMPOPTS was removed
  - the SHARED variable was removed; its value is "shared" or "noshared",
    which duplicates the existing and more convenient
    SUPPORTS_SHARED_LIBRARIES variable whose value is "true" or "false".

  Note that Makefile.config may change further in the future and relying
  on it is a bit fragile. We plan to make `ocamlc -config` easier to use
  for scripting purposes, and have a stable interface there. If you rely
  on Makefile.config, you may want to get in touch with Sébastien Hinderer
  or participate to MPR#7116 (Allow easy retrieval of Makefile.config's values)
  or MPR#7172 (More information in ocamlc -config).

The complete list of changes is listed below.

- GPR#705: update Makefile.nt so that ocamlnat compiles
  for non-Cygwin Windows ports.
  (Sébastien Hinderer, review by Alain Frisch)

- GPR#729: Make sure ocamlnat is built with a $(EXE) extension, merge
  rules between Unix and Windows Makefiles
  (Sébastien Hinderer, review by Alain Frisch)

- GPR#762: Merge build systems in the yacc/ directory.
  (Sébastien Hinderer, review by David Allsopp, Alain Frisch)

- GPR#764: Merge build systems in the debugger/ directory.
  (Sébastien Hinderer, review by Alain Frisch)

- GPR#785: Merge build systems in otherlibs/systhreads/
  (Sébastien Hinderer, review by Alain Frisch, David Allsopp,
   testing and regression fix by Jérémie Dimino)

- GPR#788: Merge build systems in subdirectories of otherlibs/.
  (Sébastien Hinderer, review by Alain Frisch)

- GPR#808, GPR#906: Merge Unix and Windows build systems
  in the ocamldoc/ directory
  (Sébastien Hinderer, review by Alain Frisch)

- GPR#812: Merge build systems in the tools/ subdirectory
  (Sébastien Hinderer, review by Alain Frisch)

- GPR#866: Merge build systems in the stdlib/ directory
  (Sébastien Hinderer, review by David Allsopp and Adrien Nader)

- GPR#941: Merge Unix and Windows build systems in the asmrun/ directory
  (Sébastien Hinderer, review by Mark Shinwell, Adrien Nader,
   Xavier Leroy, David Allsopp, Damien Doligez)

- GPR#981: Merge build systems in the byterun/ directory
  (Sébastien Hinderer, review by Adrien Nader)

- GPR#1033, GPR#1048: Merge build systems in the root directory
  (Sébastien Hinderer, review by Adrien Nader and Damien Doligez,
   testing and regression fix by Andreas Hauptmann)

### Internal/compiler-libs changes:

- GPR#673: distinguish initialization of block fields from mutation in lambda.
  (Frédéric Bour, review by Xavier Leroy, Stephen Dolan and Mark Shinwell)

- GPR#744, GPR#781: fix duplicate self-reference in imported cmi_crcs
  list in .cmti files + avoid rebuilding cmi_info record when creating
  .cmti files
  (Alain Frisch, report by Daniel Bünzli, review by Jérémie Dimino)

- GPR#881: change `Outcometree.out_variant` to be more general.
  `Ovar_name of out_ident * out_type list` becomes `Ovar_type of out_type`.
  (Valentin Gatien-Baron)

- GPR#908: refactor PIC-handling in the s390x backend
  (Gabriel Scherer)

### Bug fixes

- PR#5115: protect all byterun/fail.c functions against
  uninitialized caml_global_data (only changes the bytecode behavior)
  (Gabriel Scherer, review by Xavier Leroy)

- PR#6136, GPR#967: Fix Closure so that overapplication evaluation order
  matches the bytecode compiler and Flambda.
  (Mark Shinwell, report by Jeremy Yallop, review by Frédéric Bour)

- PR#6550, GPR#1094: Allow creation of empty .cmxa files on macOS
  (Mark Shinwell)

- PR#6594, GPR#955: Remove "Istore_symbol" specific operation on x86-64.
  This is more robust and in particular avoids assembly failures on Win64.
  (Mark Shinwell, review by Xavier Leroy, testing by David Allsopp and
   Olivier Andrieu)

- PR#6903: Unix.execvpe doesn't change environment on Cygwin
  (Xavier Leroy)

- PR#6987: Strange error message probably caused by universal variable escape
  (with polymorphic variants)
  (report by Leo White)

- PR#7216, GPR#949: don't require double parens in Functor((val x))
  (Jacques Garrigue, review by Valentin Gatien-Baron)

- PR#7331: ocamldoc, avoid infinite loop in presence of self alias,
  i.e. module rec M:sig end = M
  (Florian Angeletti, review Gabriel Scherer)

- PR#7346, GPR#966: Fix evaluation order problem whereby expressions could
  be incorrectly re-ordered when compiling with Flambda.  This also fixes one
  example of evaluation order in the native code compiler not matching the
  bytecode compiler (even when not using Flambda)
  (Mark Shinwell, Leo White, code review by Pierre Chambart)

- PR#7348: Private row variables can escape their scope
  (Jacques Garrigue, report by Leo White)

- PR#7407: Two not-quite-standard C idioms rejected by SUNWSPro compilers
  (Xavier Leroy)

- PR#7421: Soundness bug with GADTs and lazy
  (Jacques Garrigue, report by Leo White)

- PR#7424: Typechecker diverges on unboxed type declaration
  (Jacques Garrigue, report by Stephen Dolan)

- PR#7426, GPR#965: Fix fatal error during object compilation (also
  introduces new [Pfield_computed] and [Psetfield_computed] primitives)
  (Mark Shinwell)

- PR#7427, GPR#959: Don't delete let bodies in Cmmgen
  (Mark Shinwell)

- PR#7432: Linking modules compiled with -labels and -nolabels is not safe
  (Jacques Garrigue, report by Jeremy Yallop)

- PR#7437: typing assert failure with nonrec priv
  (Jacques Garrigue, report by Anil Madhavapeddy)

- PR#7438: warning +34 exposes #row with private types
  (Alain Frisch, report by Anil Madhavapeddy)

- PR#7443, GPR#990: spurious unused open warning with local open in patterns
  (Florian Angeletti, report by Gabriel Scherer)

- PR#7504: fix warning 8 with unconstrained records
  (Florian Angeletti, report by John Whitington)

- PR#7456, GPR#1092: fix slow compilation on source files containing a lot
  of similar debugging information location entries
  (Mark Shinwell)

- GPR#805, GPR#815, GPR#833: check for integer overflow in String.concat
  (Jeremy Yallop,
   review by Damien Doligez, Alain Frisch, Daniel Bünzli, Fabrice Le Fessant)

- GPR#810: check for integer overflow in Array.concat
  (Jeremy Yallop)

- GPR#814: fix the Buffer.add_substring bounds check to handle overflow
  (Jeremy Yallop)

- GPR#881: short-paths did not apply to some polymorphic variants
  (Valentin Gatien-Baron, review by Leo White)

- GPR#886: Fix Ctype.moregeneral's handling of row_name
  (Leo White)

- GPR#934: check for integer overflow in Bytes.extend
  (Jeremy Yallop, review by Gabriel Scherer)

- GPR#956: Keep possibly-effectful expressions when optimizing multiplication
  by zero.
  (Jeremy Yallop)

- GPR#977: Catch Out_of_range in ocamldebug's "list" command
  (Yunxing Dai)

- GPR#983: Avoid removing effectful expressions in Closure, and
  eliminate more non-effectful ones
  (Alain Frisch, review by Mark Shinwell and Gabriel Scherer)

- GPR#987: alloc_sockaddr: don't assume a null terminator. It is not inserted
  on macOS by system calls that fill in a struct sockaddr (e.g. getsockname).
  (Anton Bachin)

- GPR#998: Do not delete unused closures in
  (Leo White)

- GPR#1019: Fix fatal error in Flambda mode "[functions] does not map set of
  closures ID"
  (Pierre Chambart, code review by Mark Shinwell and Leo White)

- GPR#1075: Ensure that zero-sized float arrays have zero tags.
  (Mark Shinwell, Leo White)

* GPR#1088: Gc.minor_words now returns accurate numbers.
  (Stephen Dolan)

Intel Skylake / Kaby Lake hardware bug affects OCaml programs


Xavier Leroy announced:
It was recently made public that Intel processors of the Skylake and Kaby Lake
families have a nasty hardware bug concerning hyperthreading. See, for example

I wanted to draw the attention of all OCaml users to this issue, because this
hardware bug is triggered by the OCaml runtime under fairly common conditions.
Random crashes caused by this bug were observed at Ahrefs and another industrial
user of OCaml, and also by users of Coccinelle and of Coq. (*)

Your OCaml installation may be affected if the following three conditions are met:

1- You're using an Intel processor of the Skylake or Kaby Lake family.
   (AMD processors and older Intel processors are not affected.)
2- The processor support hyperthreading (HT) and hyperthreading is enabled in
   the BIOS.

3- The OCaml runtime system was compiled with certain versions of GCC.
   (We don't know exactly which versions of GCC triggers the issue, but
    it seems that it is never triggered by clang-generated code.
    In particular, this means that Mac OS X users should be safe.)

See for help in
determining if your processor is vulnerable, and for instructions on how to
address the issue. Possible fixes include:

- Apply the microcode update recently released by Intel for Skylake processors.
(No such update exists yet for Kaby Lake processors.)
- Disable hyperthreading in the BIOS.
- Reinstall OCaml using clang instead of GCC.

Kind regards,

- Xavier Leroy

(*) It is likely that we OCaml folks were the first to pinpoint this Intel bug.
For more information, see the narratives at
Xavier Leroy then added:

> Possible fixes include:
> - Apply the microcode update recently released by Intel [...]

Contradicting what I wrote before, microcode updates are available both for
Skylake and for Kaby Lake processors. It's only how to apply those updates that
differs slightly between Skylake and Kaby Lake. Again, see the excellent
instructions at

Sorry for the confusion.
Gabriel Scherer then said:
Here is my list of affected OCaml projects known so far (it seems
surprisingly less rare than I thought at first):

- an (unnamed) industrial user noticed the issue in Spring 2016, as
  reported by Xavier on the bugtracker:

- ahrefs noticed issues in late 2016, as reported by Joris
  Giovannangeli on the bugtracker issue or his longer piece

- Lwt users were also affected (first report from Sebastien Mondet in
  February 2017):

- Julia Lawall reported segfaults from a downstream user on the caml-list,
  that seem extreley likely to be related to this issue (they
  disappear with hyperthreading disabled)

At this point it seems reasonable to assume that any
computation-intensive OCaml program that is run in parallel may be
Emilio Jesús Gallego Arias also added:
Here is the only Coq bug that I know of:

but as Maxime pointed out, the problem was observed by other people

From the OCaml discourse

The editor compiled this list:
Here are some links to messages at that may
be of interest to the readers.

- Jochen Bartl talks about "Functional Geekery Episode 99 - Christiano
- Louis Gesbert talks about "opam-bundle 0.1: generate self-contained,
  distributable source package bundles"
- Louis Gesbert talks about "opam-package-upgrade 0.1: a small tool to migrate
  `opam` files to 2.0 format"
- Anton Bachin talks about "Lwt core refactored and documented to be
- Joris Giovannangeli talks about "Skylake bug: a detective story"
- kevingray talks about "OPAM Experiment and future Developer Experience

Ocaml Github Pull Requests

Gabriel Scherer and the editor compiled this list:
Here is a sneak peek at some potential future features of the Ocaml
compiler, discussed by their implementers in these Github Pull Requests.

- Restrict Unix.environment in privileged contexts; add Unix.unsafe_environment

Other OCaml News

From the ocamlcore planet blog:
Here are links from many OCaml blogs aggregated at OCaml Planet,

How I found a bug in Intel Skylake processors

OCaml server-side developer at Ahrefs (Full-time)

Old cwn

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Alan Schmitt