September 2026 - Haskell-Cafe

GHC 10.0.1-alpha1 is now available
by Zubin Duggal 20 Sep '26

20 Sep '26

The GHC developers are very pleased to announce the availability of the first alpha prerelease of GHC 10.0.1. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org][] and via [GHCup](https://www.haskell.org/ghcup/). GHC 10.0 will bring a number of new features and improvements, including: * The default language edition is now `GHC2024` ([GHC Proposal #632][ghc2024], #26039). * `Type` and `Constraint` are now completely distinct types, just as much as `Int` and `Bool` (#24279). * The new [QualifiedStrings][] language extension ([GHC Proposal #723][qualified-strings]) allows string literals to be qualified using module qualification syntax, so that `M."my string"` desugars to`M.fromString "my string"`. * The treatment of static forms has been simplified, implementing [GHC Proposal #732][static-forms] (#26556). The free term variables of `(static e)` must now be bound at top level. * `-fpolymorphic-specialisation` is now (re)enabled by default (#23559), * Bytecode can now be written to disk with `-fwrite-byte-code` and packaged into bytecode libraries with `-bytecodelib`, which the interpreter can use to satisfy package dependencies (#26298). * Executables can now be properly statically linked with the new `-fully-static` and `-static-external` flags (#26434). * SIMD support in the AArch64 native code generator (#26536). * A new `poll` I/O manager, which is now the default in the single-threaded RTS on all POSIX platforms except macOS (!9677). * Version 2 of the [GHC Jobserver Protocol][jsem] for GHC's `-jsem` jobserver on Linux and other POSIX platforms (#25087, #27253). This is sadly a necessary breaking change. `-jsem` requires cabal-install 3.18 or later, and is otherwise ignored with a warning, falling back to sequential compilation. * Changes to `base`: * `GHC.Num.{BigNat,Integer,Natural}` are no longer exposed ([CLC #359][clc-359]) and GHC internals in `GHC.Num` are deprecated ([CLC #360][clc-360]). * `Data.List.init` and `Data.List.last` now carry an `x-partial` warning ([CLC #292][clc-292]). * The minimum bootstrap compiler is now GHC 9.10, LLVM versions up to 23 are supported (#26813, #27764), and the Debian 9, Debian 10, Ubuntu 18.04 and Ubuntu 20.04 bindists have been dropped in favour of a new Debian 13 bindist (#25876). * ... and many more A full accounting of changes can be found in the [release notes][]. See the [migration guide][] for guidance on migrating programs to this release. As always, GHC's release status, including planned future releases, can be found on the GHC Wiki [status][]. Given the many changes in this major release, we would very much appreciate testing on downstream workloads. GHC development is sponsored by: * [Juspay](https://juspay.com/) * [QBayLogic](https://qbaylogic.com/) * [Channable](https://www.channable.com/) * [Haskell Foundation](https://haskell.foundation/) * [Serokell](https://serokell.io/) * [Well-Typed](https://well-typed.com/) * [Tweag](https://www.tweag.io/) * [Dotcom-Monitor](https://www.dotcom-monitor.com/) * [LoadView](https://www.loadview-testing.com/) * [Web Hosting Buddy](https://webhostingbuddy.com/) * [Find My Electric](https://www.findmyelectric.com/) * [Standard Chartered](https://www.sc.com) * [UpCloud](https://upcloud.com) * [Mercury](https://mercury.com) We would like to thank these sponsors and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. As always, do give this release a try and open a [ticket][] if you see anything amiss. [downloads.haskell.org] https://downloads.haskell.org/ghc/10.0.1-alpha1 [release notes]: https://downloads.haskell.org/ghc/10.0.1-alpha1/docs/users_guide/10.0.1-not… [migration guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/10.0 [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [ghc2024]: https://github.com/ghc-proposals/ghc-proposals/pull/632 [static-forms]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0732-s… [QualifiedStrings]: https://downloads.haskell.org/ghc/10.0.1-alpha1/docs/users_guide/exts/quali… [qualified-strings]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0723-q… [jsem]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0540-j… [clc-292]: https://github.com/haskell/core-libraries-committee/issues/292 [clc-359]: https://github.com/haskell/core-libraries-committee/issues/359 [clc-360]: https://github.com/haskell/core-libraries-committee/issues/360

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GHC 9.14.2-rc2 is now available
by Zubin Duggal 17 Sep '26

17 Sep '26

The GHC developers are very pleased to announce the availability of the second release candidate for GHC 9.14.2. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org][] and via [GHCup](https://www.haskell.org/ghcup/). See also the [previous announcement of 9.14.2-rc1][rc1]. The changes since the first release candidate are: * Several fixes to the specialiser and demand analyser for miscompilations causing incorrect runtime results, crashes, or hangs (#27626, #27627, #27629, #27703, #27704, #27705, #27717). * Fixes for a number of runtime system bugs: * a missing memory barrier in the parallel garbage collector, which could crash or silently corrupt the heap on weakly-ordered architectures such as AArch64 (#27477). * a use-after-free with TSOs (#26716, #26717). * an "unknown/strange object" crash in the compacting collector when collecting the large data constructors that the bytecode interpreter allocates (#27649). * a segfault when querying the label of an unlabelled thread (#27618). * a crash when capturing or resuming a delimited continuation that adjusts the asynchronous exception masking state (#27651). * stack corruption when returning large unboxed tuples in GHCi (#27633). * Further fixes to the AArch64 native code generator, addressing bugs that caused incorrect runtime results from subword operations (#27430, #27533, #27537, #27538, #27539, #27550). * `toException` for `SomeException` no longer drops the attached `ExceptionContext`, and a `catchSTM` handler no longer breaks `retry` or asynchronous exception delivery (#27455, #27657). * Reduced memory usage with multiple home units (#26423, #27308, #27500, #27748). * Fixes for panics and spurious out-of-scope errors involving type arguments in pattern synonym right-hand sides (#27440, #27583, #27586). * The pattern-match checker now recognises `considerAccessible` under ticks, and no longer emits a spurious `-Wincomplete-uni-patterns` warning under `-finfo-table-map` (#27314, #27360). * The deprecation warning for static forms, added in rc1, no longer fires on free type variables (#27664). * A fix for a regression preventing modules from being loaded into GHCi after startup (#27202, #27640). * A fix for representation-polymorphism checks producing a coercion that fails Core Lint (#27639). * Support for LLVM up to version 23 (#27764). * Updates for libffi (3.8.0), `directory` (1.3.11.0), `file-io` (0.1.6), `haskeline` (0.8.5.0) and `os-string` (2.0.10). GHC 9.14.2 is a bug-fix release fixing many issues of a variety of severities and scopes, including: * Version 2 of the [GHC Jobserver Protocol][jsem] for GHC's `-jsem` jobserver on Linux and other POSIX platforms (#25087, #27253). This is sadly a necessary breaking change: `-jsem` requires cabal-install 3.18 or later, and is otherwise ignored with a [warning][jsem-warning], falling back to sequential compilation. * A new deprecation warning for static forms that mention nested let-bound variables. This will become an error in GHC 10.0 ([GHC Proposal #732][static-forms], #26718). * A fix for a CorePrep miscompilation that could project a field out of an absent dictionary, resulting in a segfault (#25924). * A fix for demand analysis giving an absent demand to an argument that was still used by the function's stable unfolding, which could cause a runtime crash (#26416). * Numerous fixes for register allocation and Cmm register-conflict analysis bugs, preventing incorrect code generation and corruption of vector registers when spilling and reloading (#26411, #26526, #26537, #26542, #26550, #26668). * Many NCG fixes on AArch64: `MOVK` clobbering live values (#26980), register clobbering and an incorrect overflow bit in `MUL2` (#27046, #27047), and incorrect sign extension (#26978) and unsigned right shift (#26979) at subword widths. * A fix for a stack alignment bug on x86 that could cause segfaults or corrupted registers when using AVX/AVX-512 vector code (#26595, #26822). * Fixes for several black hole handling bugs that could lead to deadlocks or crashes in multithreaded programs, showing up as hangs or "END_TSO_QUEUE object entered" errors (#26922, #26936). * Fixes for many other runtime system crashes and races (#26341, #26573, #26640, #27007, #27008, #27009, #27082). * A fix for an "unknown/strange object" crash in the compacting garbage collector (#27434). * Fixes for split sections on Windows (#26696, #26494) and the LLVM backend (#26770). * Fixes for the Wasm backend (#26916, #27257), and the RISC-V (#27300, #27303, #27306) and PowerPC (#23969, #24145, #26828) native code generators. * The JavaScript backend now supports more than 128 registers, fixing runtime `ReferenceError` failures for functions taking very many arguments (#26558). * Correctness and performance improvements in the bytecode interpreter (#12953, #26287, #26946, #26995, #27001). * Fixes for several compiler panics, including issues with SetLevels (#26681), the type-class specialiser (#26682), `mkTick` (#26772, #27121), CoreToStg (#27182, #27386), the pattern-match checker (#25926, #27124), module graph reachability (#26568), and continuation trimming for bottoming functions (#27261). * Fixes for several cases where the compiler could hang or loop, including with negative type literals (#26861), deep subsumption (#26823), and when simplifying the right-hand sides of rewrite rules (#26323, #26826). * A fix for cast worker/wrapper incorrectly firing on INLINE functions (#26903). * A fix for exponential-time desugaring of nested `case` expressions (#27383, #20251). * A fix for a regression that caused overloaded functions to no longer be specialised as effectively as in previous releases, hurting runtime performance (#26831). * A fix for associated type family and data family instance changes not triggering recompilation (#26183, #26705). * Fixes for Explicit Level Imports and Template Haskell staging (#26088, #26098, #26099, #26616, #27385). * Improvements to determinism of compiler output, including the order in which `:info` lists instances (#26846, #26858, #26877, #27532). * Additions for GHCi and GHC API users: the `-fimport-loaded-targets` flag (#26866), custom external interpreter commands (#26652), `decodeStackWithIpe` and related stack-decoding helpers (#27065), an optional `SrcLoc` on `StackAnnotation` (#26806), and a `gc_sync_elapsed_ns` counter in `RTSStats` (#26944). * ... and many more. A full accounting of these fixes can be found in the [release notes][]. As always, GHC's release status, including planned future releases, can be found on the GHC Wiki [status][]. This release candidate will have a two-week testing period. If all goes well the final release will be available the week of 1 October 2026. GHC development is sponsored by: * [Juspay](https://juspay.com/) * [QBayLogic](https://qbaylogic.com/) * [Channable](https://www.channable.com/) * [Haskell Foundation](https://haskell.foundation/) * [Serokell](https://serokell.io/) * [Well-Typed](https://well-typed.com/) * [Tweag](https://www.tweag.io/) * [Dotcom-Monitor](https://www.dotcom-monitor.com/) * [LoadView](https://www.loadview-testing.com/) * [Web Hosting Buddy](https://webhostingbuddy.com/) * [Find My Electric](https://www.findmyelectric.com/) * [Standard Chartered](https://www.sc.com) * [UpCloud](https://upcloud.com) * [Mercury](https://mercury.com) We would like to thank these sponsors and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. As always, do give this release a try and open a [ticket][] if you see anything amiss. [release notes]: https://gitlab.haskell.org/ghc/ghc/-/blob/ghc-9.14/docs/users_guide/9.14.2-… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [downloads.haskell.org] https://downloads.haskell.org/ghc/9.14.2-rc2 [jsem]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0540-j… [static-forms]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0732-s… [jsem-warning]: https://downloads.haskell.org/ghc/9.14.2-rc2/docs/users_guide/using-warning… [rc1]: https://www.haskell.org/ghc/blog/20260730-ghc-9.14.2-rc1-released.html [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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PAgE'27 Call for Papers (co-located with POPL'27)
by Ningning Xie 16 Sep '26

16 Sep '26

PAgE 2027 Call for Papers https://popl27.sigplan.org/home/page-2027 PAgE (Principles of Agentic Engineering) aims to bring together the formal methods and AI communities to advance the principles of safe agentic engineering. It will feature peer-reviewed papers and invited talks from experts in the field. We welcome submissions describing research results, artifacts, datasets, case studies, and experience reports. Topics of interest include, but are not limited to: - Specifications and type-safe interfaces for tool use - Memory and state management for agents - Reliability & groundedness in planning and tool use - Static & dynamic analysis and verification of agentic plans - Safe integration with software engineering workflows - Testing and debugging of agentic workflows - Runtimes, compilers and virtual machines for agentic programs - Evaluation methods and benchmarks for trustworthy agents and agentic software, including safety, reliability, and cost/latency tradeoffs - Safety, security, and privacy of multi-agent systems - Neuro-symbolic and formal methods approaches for agent reasoning and control We also welcome submissions that explore the use of AI agents in the research and development process itself, including agent-assisted ideation, implementation, experimentation, artifact generation, and writing. Such submissions should clearly describe the workflow used, the extent of human oversight, and any lessons learned regarding reliability, reproducibility, and safety. We encourage submissions describing work in progress, position papers, experience reports, negative results (with detailed analysis and hypotheses for future improvements), demos, artifact or dataset descriptions, and talk proposals. Accepted submissions will be presented at the workshop but will not appear in the ACM Digital Library. You are free to submit work for presentation that is or will be published elsewhere. Please ensure that all submissions are anonymized for review. Submissions may be up to 8 pages, excluding bibliography, and should use the standard SIGPLAN conference two-column format.

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FPBT'27 Call for Papers (co-located with POPL'27)
by Ningning Xie 16 Sep '26

16 Sep '26

Call for Papers https://popl27.sigplan.org/home/fpbt-2027 We are excited to announce that the first annual Future of Property-Based Testing Workshop (FPBT'27) will be happening in Mexico City on January 12th (co-located with POPL'27)! FPBT will bring together researchers and educators who work on and teach PBT to talk about what technical advances the research community should focus on in the coming years, and how we can best bring PBT to the next generation of software developers. Submissions are open now (deadline October 23rd); see https://popl27.sigplan.org/home/fpbt-2027 for details.

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[TFP 2027] Call for Papers for the 28th International Symposium on Trends in Functional Programming, Kyoto, Japan, March 2027
by Peter Achten 14 Sep '26

14 Sep '26

# TFP 2027 - Call for Papers (https://trendsfp.github.io/2027/) ## Important Dates Submission deadline (pre-symposium, full papers): Thu 3rd Dec 2026 (AOE) Notification (pre-symposium, full papers): Thu 14th Jan 2027 Submission deadline (pre-symposium, draft papers): Thu 28th Jan 2027 (AOE) Notification (pre-symposium, draft papers): Thu 4th Feb 2027 Submission deadline (post-symposium review): Thu 29th Apr 2027 (AOE)* Notification (post-symposium submissions): Thu 10th Jun 2027* TFPiE Workshop: Mon 12th Mar 2027 TFP Symposium: Sat 13th to Mon 15th Mar 2027 (* tentative) The Symposium on Trends in Functional Programming (TFP) is an international forum for researchers with interests in all aspects of functional programming, taking a broad view of current and future trends in the area. It aspires to be a lively environment for presenting the latest research results, and other contributions. This year, TFP will take place in-person in Kyoto, Japan, held by the Special Interest Group on Programming and Programming Languages (SIG-PPL), Japan Society for Software Science and Technology (JSSST). It is co-located with the Trends in Functional Programming in Education (TFPIE) workshop, which will take on the day before the main symposium. Please be aware that TFP has several submission deadlines. The first, 3rd of December, is for authors who wish to have their full paper reviewed prior to the symposium. Papers that are accepted in this way must also be presented at the symposium. The second, 28th January, is for authors who wish to present their work or work-in-progress at the symposium first without submitting to the full review process for publication. These authors can then take into account feedback received at the symposium and submit a full paper for review by the third deadline, Thu 29th Apr 2027 (AOE) (tentative). ## Scope The symposium recognizes that new trends may arise through various routes. As part of the Symposium's focus on trends we therefore identify the following five paper categories. High-quality submissions are solicited in any of these categories: * Research Papers: Leading-edge, previously unpublished research work * Position Papers: On what new trends should or should not be * Project Papers: Descriptions of recently started new projects * Evaluation Papers: What lessons can be drawn from a finished project * Overview Papers: Summarizing work with respect to a trendy subject Papers must be original and not simultaneously submitted for publication to any other forum. They may consider any aspect of functional programming: theoretical, implementation-oriented, or experience-oriented. Applications of functional programming techniques to other languages are also within the scope of the symposium. Topics suitable for the symposium include, but are not limited to: * Functional programming and multicore/manycore computing * Functional programming in the cloud * High performance functional computing * Extra-functional (behavioural) properties of functional programs * Dependently typed functional programming * Validation and verification of functional programs * Debugging and profiling for functional languages * Functional programming in different application areas: security, mobility, telecommunications applications, embedded systems, global computing, grids, etc. * Interoperability with imperative programming languages * Novel memory management techniques * Program analysis and transformation techniques * Empirical performance studies * Abstract/virtual machines and compilers for functional languages * (Embedded) domain specific languages * New implementation strategies * Any new emerging trend in the functional programming area If you are in doubt on whether your paper is within the scope of TFP, please contact the programme chairs, Alex Gerdes and Kazutaka Matsuda. ## Best Paper Awards TFP awards two prizes for the best papers each year. First, to reward excellent contributions, TFP awards a prize for the best overall paper accepted for the post-conference formal proceedings. Second, each year TFP also awards a prize for the best student paper. TFP traditionally pays special attention to research students, acknowledging that students are almost by definition part of new subject trends. A student paper is one for which the authors state that the paper is mainly the work of students, the students are the paper's first authors, and a student would present the paper. In both cases, it is the PC of TFP that awards the prize. In case the best paper happens to be a student paper, then that paper will receive both prizes. ## Instructions to Authors Submission is via EasyChair: <https://easychair.org/conferences/?conf=tfp2027>. Authors of papers have the choice of having their contributions formally reviewed either before or after the Symposium. Further, pre-symposium submissions may either be full (earlier deadline) or draft papers (later deadline). ## Pre-symposium formal review Papers to be formally reviewed before the symposium should be submitted before the early deadline and will receive their reviews and notification of acceptance for both presentation and publication before the symposium. A paper that has been rejected for publication but accepted for presentation may be revised and resubmitted for the post-symposium formal review. ## Post-symposium formal review Draft papers will receive minimal reviews and notification of acceptance for presentation at the symposium. Authors of draft papers will be invited to submit revised papers based on the feedback received at the symposium. A post-symposium refereeing process will then select a subset of these papers for formal publication. ## Paper categories Draft papers and papers submitted for formal review are submitted as extended abstracts (4 to 10 pages in length) or full papers (up to 20 pages). The submission must clearly indicate which category it belongs to: research, position, project, evaluation, or overview paper. It should also indicate which authors are research students, and whether the main author(s) are students. A draft paper for which all authors are students will receive additional feedback by one of the PC members shortly after the symposium has taken place. ## Format Papers must be written in English, and written using the LNCS style. For more information about formatting please consult the Springer LNCS Guidelines web site (https://www.springer.com/gp/computer-science/lncs/conference-proceedings-gu…) ## Organizing Committee Alex Gerdes University of Gothenburg and Chalmers, SE Program Co-Chair Kazutaka Matsuda Tohoku University, JP Program Co-Chair SIG-PPL Coordination Atsushi Igarashi Kyoto University, JP Local Arrangements Chair Kota Mizushima nextbeat Co., Ltd Sponsorship Chair Casper Bach University of South Denmark, DK General Chair Peter Achten Radboud University Nijmegen, NL Publicity Chair Marco T. Morazán Seton Hall University, US Steering Committee Chair ## Programme Committee <TBA>

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Call for Contributions: BOB 2027 (Berlin, Feb 26 - Deadline Nov 2)
by Michael Sperber 03 Sep '26

03 Sep '26

================================================================================ BOB Conference 2027 "What happens when we use what's best for a change?" https://bobkonf.de/2027/cfc.html Berlin, Feb 26 Call for Contributions Deadline: November 2, 2026 ================================================================================ You are actively engaged in advanced software engineering methods, solve ambitious problem with software and are open to cutting-edge innovation? Attend this conference, meet people that share your goals, and get to know the best software tools and technologies available today. We strive to offer a day full of new experiences and impressions that you can use to immediately improve your daily life as a software developer. If you share our vision and want to contribute, submit a proposal for a talk or tutorial! NOTE: The conference fee will be waived for presenters. Travel expenses will not be covered (for exceptions see "Speaker Grants"). Shepherding ----------- The program committee offers shepherding to all speakers. Shepherding provides speakers assistance with preparing their sessions. Specifically: - advice on structure and presentation - review of talk slides Speaker Grants -------------- BOB has Speaker Grants available to support speakers from groups under-represented in technology. We specifically seek women speakers, speakers of color, and speakers who are not able to attend the conference for financial reasons. Topics ------ We are looking for talks about best-of-breed software technology, e.g.: - functional programming - persistent data structures and databases - event-based modelling and architecture - "fancy types" (dependent types, gradual typing, linear types, ...) - formal methods for correctness and robustness - abstractions for concurrency and parallelism - metaprogramming - probabilistic programming - math and programming - controlled side effects - program synthesis - AI beyond chatbots, vibecoding, and agents - linked data - symbolic AI - next-generation IDEs - effective abstractions for data analytics - ... everything really that isn’t mainstream, but you think should be - ... including rough ideas that are worth discussing. Presenters should provide the audience with information that is practically useful for software developers. Challenges ---------- Furthermore, we seek contributions on successful approaches for solving hard problems, for example: - bias in machine-learning systems - digital transformation in difficult settings - accessibiltity - systems with critical reliability requirements - ecologically sustainable software development We're especially interested in experience reports. Other topics are also relevant, e.g.: - introductory talks on technical background - overviews of a given field - demos and how-tos Requirements ------------ We accept proposals for presentations of 45 minutes (40 minutes talk + 5 minutes questions), as well as 90 minute tutorials for beginners. The language of presentation should be either English or German. Your proposal should include (in your presentation language of choice): - An abstract of max. 1500 characters. - A short bio/cv - Contact information (including at least email address) - A list of 3-5 concrete ideas of how your work can be applied in a developer's daily life - additional material (websites, blogs, slides, videos of past presentations, …) Organisation ------------ - Direct questions to konferenz at bobkonf dot de - Proposal deadline: November 2, 2026 - Notification: November 23, 2026 - Program: November 30, 2026 Submit here: https://pretalx.com/bob-2027/submit/ Program Committee ----------------- (more information here: https://bobkonf.de/2027/programmkomitee.html) - Matthias Fischmann, Wire - Matthias Neubauer, SICK AG - Nicole Rauch, Softwareentwicklung und Entwicklungscoaching - Michael Sperber, Active Group - Stefan Wehr, Hochschule Offenburg Scientific Advisory Board - Annette Bieniusa, TU Kaiserslautern - Torsten Grust, Uni Tübingen - Peter Thiemann, Uni Freiburg

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