# Internals & Design

**URL:** https://discourse.julialang.org/c/dev/5.md?no_subcategories=false

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

---

## [About the Internals & Design category](https://discourse.julialang.org/t/about-the-internals-design-category/13)

<div class="topic-metadata">

**Author:** [@vchuravy](https://discourse.julialang.org/u/vchuravy)\
**Replies:** 0\
**Last updated:** [October 19, 2016, 2:58am UTC](https://discourse.julialang.org/t/about-the-internals-design-category/13 "2016-10-19T02:58:29Z")

</div>

Discussion of the development of Julia itself: language design, implementation and standard library. For questions about using Julia, use the Usage category. To reduce noise, users must be at least trust level one (basi…

---

## [Should Julia guarantee semi-monotonic where appropriate (or even monotonic) math? Such as trancendentals](https://discourse.julialang.org/t/should-julia-guarantee-semi-monotonic-where-appropriate-or-even-monotonic-math-such-as-trancendentals/140346)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 18\
**Last updated:** [October 30, 2026, 9:10pm UTC](https://discourse.julialang.org/t/should-julia-guarantee-semi-monotonic-where-appropriate-or-even-monotonic-math-such-as-trancendentals/140346 "2026-10-30T21:10:36Z")

</div>

Continuing the discussion from Formalizing Julia in Lean (and finding 400+ bugs in Base): I see at the Java docs \[see linked from the issue\] even the sine function is guaranteed semi-monotonic… Semi-monotonic doesn’t i…

---

## [What is the intended scope of \`TypeEgal\`'s exposure?](https://discourse.julialang.org/t/what-is-the-intended-scope-of-typeegal-s-exposure/140194)

<div class="topic-metadata">

**Author:** [@kimikage](https://discourse.julialang.org/u/kimikage)\
**Replies:** 1\
**Last updated:** [October 24, 2026, 12:35pm UTC](https://discourse.julialang.org/t/what-is-the-intended-scope-of-typeegal-s-exposure/140194 "2026-10-24T12:35:56Z")

</div>

Julia 1.14.0-alpha1 has been released, so I’d like to ask a question. Starting with Julia 1.14, end-users will easily encounter TypeEgal. julia\> VERSION v"1.14.0-alpha1" julia\> zero(String) ERROR: MethodError: no meth…

---

## [Moving away from "manual JLL packages" in the General registry](https://discourse.julialang.org/t/moving-away-from-manual-jll-packages-in-the-general-registry/135754)

<div class="topic-metadata">

**Author:** [@dilumaluthge](https://discourse.julialang.org/u/dilumaluthge)\
**Replies:** 40\
**Last updated:** [October 21, 2026, 9:20am UTC](https://discourse.julialang.org/t/moving-away-from-manual-jll-packages-in-the-general-registry/135754 "2026-10-21T09:20:45Z")

</div>

By “manual JLL”, I mean a JLL package that does not come from Yggdrasil, the Julia community build tree. In the past, we’ve allowed some manual JLLs to be registered in the General registry. However, after some internal…

---

## [Julia 1.14 feature freeze: Monday, October 12, 2026](https://discourse.julialang.org/t/julia-1-14-feature-freeze-monday-october-12-2026/139560)

<div class="topic-metadata">

**Author:** [@dilumaluthge](https://discourse.julialang.org/u/dilumaluthge)\
**Replies:** 7\
**Last updated:** [October 17, 2026, 7:16pm UTC](https://discourse.julialang.org/t/julia-1-14-feature-freeze-monday-october-12-2026/139560 "2026-10-17T19:16:41Z")

</div>

We have set the feature freeze for Julia 1.14 to Monday, October 12, 2026. If there are any feature PRs that you’d like to get into Julia 1.14, they’ll need to be merged prior to that date. EDIT: We extended the freeze…

---

## [What was the motivation behind Julia's staging (specialization, macro, generated function, etc.) systems design?](https://discourse.julialang.org/t/what-was-the-motivation-behind-julias-staging-specialization-macro-generated-function-etc-systems-design/139978)

<div class="topic-metadata">

**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 7\
**Last updated:** [October 14, 2026, 7:00am UTC](https://discourse.julialang.org/t/what-was-the-motivation-behind-julias-staging-specialization-macro-generated-function-etc-systems-design/139978 "2026-10-14T07:00:20Z")

</div>

▶ Background (what I learned trying to make a language even though it didn't work out due to unforeseen difficulty my naive mind didn't see coming.) So, the key to performance in a dynamic language is staging. Runtime cod…

---

## [Should zipping with an infinite iterator preserve iterator shape?](https://discourse.julialang.org/t/should-zipping-with-an-infinite-iterator-preserve-iterator-shape/140009)

<div class="topic-metadata">

**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 0\
**Last updated:** [October 13, 2026, 7:44pm UTC](https://discourse.julialang.org/t/should-zipping-with-an-infinite-iterator-preserve-iterator-shape/140009 "2026-10-13T19:44:57Z")

</div>

Currently, Base.IteratorSize(zip(iterators...)) is never Base.HasShape when any iterator in iterators is infinite (when its IteratorSize is Base.IsInfinite). At best the IteratorSize is HasLength. I feel it may make sen…

---

## [Use of MurmurHash3 for hashing strings](https://discourse.julialang.org/t/use-of-murmurhash3-for-hashing-strings/9818)

<div class="topic-metadata">

**Author:** [@ScottPJones](https://discourse.julialang.org/u/ScottPJones)\
**Replies:** 33\
**Last updated:** [October 12, 2026, 4:44pm UTC](https://discourse.julialang.org/t/use-of-murmurhash3-for-hashing-strings/9818 "2026-10-12T16:44:35Z")

</div>

Julia uses the 128 bit MurmurHash3 algorithm for the hash function for AbstractString. There are two serious issues with that: It is not possible to build up a hash value for a string in chunks: julia\> hash("bar",has…

---

## [Invalidations caused by FixedPointNumbers and GeometryBasics](https://discourse.julialang.org/t/invalidations-caused-by-fixedpointnumbers-and-geometrybasics/139232)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 6\
**Last updated:** [October 11, 2026, 8:38pm UTC](https://discourse.julialang.org/t/invalidations-caused-by-fixedpointnumbers-and-geometrybasics/139232 "2026-10-11T20:38:04Z")

</div>

The FixedPointNumbers package is causing many invalidations, even though it does not engage in type piracy. For details, see: Loading FixedPointNumbers invalidates ~7,700 precompiled method instances (7x slower first mtk…

---

## [Building an incremental sysimage in seconds instead of minutes](https://discourse.julialang.org/t/building-an-incremental-sysimage-in-seconds-instead-of-minutes/139352)

<div class="topic-metadata">

**Author:** [@melevy](https://discourse.julialang.org/u/melevy)\
**Replies:** 1\
**Last updated:** [October 7, 2026, 3:52am UTC](https://discourse.julialang.org/t/building-an-incremental-sysimage-in-seconds-instead-of-minutes/139352 "2026-10-07T03:52:13Z")

</div>

Disclaimer: this post was written using AI, but I did my best to make this informative and useful for others. The post has been flagged for being an advertisement, it is not. I hope it passes this time. This is a resear…

---

## [\[a,b,c,d\] for a,b,c,d::Union{Float64,Int} fails type prediction at seemingly no benefit](https://discourse.julialang.org/t/a-b-c-d-for-a-b-c-d-union-float64-int-fails-type-prediction-at-seemingly-no-benefit/139515)

<div class="topic-metadata">

**Author:** [@skraemer](https://discourse.julialang.org/u/skraemer)\
**Replies:** 2\
**Last updated:** [October 2, 2026, 2:24pm UTC](https://discourse.julialang.org/t/a-b-c-d-for-a-b-c-d-union-float64-int-fails-type-prediction-at-seemingly-no-benefit/139515 "2026-10-02T14:24:56Z")

</div>

I have recently already asked related questions, but type prediction for union types has unfortunately become a gift for me that keeps on giving. Replacing Base.promote\_typeof by a simpler implementation seems at no los…

---

## [Extending Linear Algebra for Units](https://discourse.julialang.org/t/extending-linear-algebra-for-units/139761)

<div class="topic-metadata">

**Author:** [@Deduction42](https://discourse.julialang.org/u/Deduction42)\
**Replies:** 2\
**Last updated:** [October 1, 2026, 3:04pm UTC](https://discourse.julialang.org/t/extending-linear-algebra-for-units/139761 "2026-10-01T15:04:28Z")

</div>

I’m the author of the FlexUnits.jl library and I’ve currently built some functionality around linear algebra and unitful matrices. The key behind efficient linear algebra is to factor the units of an MxN matrix into a Li…

---

## [Slurping on non-final argument](https://discourse.julialang.org/t/slurping-on-non-final-argument/79225)

<div class="topic-metadata">

**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 5\
**Last updated:** [September 28, 2026, 11:56pm UTC](https://discourse.julialang.org/t/slurping-on-non-final-argument/79225 "2026-09-28T23:56:04Z")

</div>

why can i define this function? julia\> f(y,x...)=+(x...).\*y f (generic function with 1 method) and can’t I define this other one? julia\> f1(x...,y)=+(x...).\*y ERROR: syntax: invalid "..." on non-final Couldn’t we g…

---

## [Consider adding splat and slurp functions](https://discourse.julialang.org/t/consider-adding-splat-and-slurp-functions/34606)

<div class="topic-metadata">

**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 2\
**Last updated:** [September 28, 2026, 9:26am UTC](https://discourse.julialang.org/t/consider-adding-splat-and-slurp-functions/34606 "2026-09-28T09:26:18Z")

</div>

Already several times it was discussed that we might add the splat function to Base that would have the following definition: splat(f) = x -\> f(x...) then we could also consider adding: slurp(f) = (x...) -\> f(x) (the…

---

## [Type Constructors (=multiple dispatch for \`UnionAll\`)](https://discourse.julialang.org/t/type-constructors-multiple-dispatch-for-unionall/139622)

<div class="topic-metadata">

**Author:** [@PatrickHaecker](https://discourse.julialang.org/u/PatrickHaecker)\
**Replies:** 13\
**Last updated:** [September 27, 2026, 7:58pm UTC](https://discourse.julialang.org/t/type-constructors-multiple-dispatch-for-unionall/139622 "2026-09-27T19:58:08Z")

</div>

TL;DR Let’s use (static) multiple dispatch for UnionAll type application! This would introduce type constructors. They would take a UnionAll to construct a type similar to how inner (object/value) constructors take a ty…

---

## [Julia master is not responsive on startup](https://discourse.julialang.org/t/julia-master-is-not-responsive-on-startup/139651)

<div class="topic-metadata">

**Author:** [@matthias314](https://discourse.julialang.org/u/matthias314)\
**Replies:** 3\
**Last updated:** [September 25, 2026, 8:37pm UTC](https://discourse.julialang.org/t/julia-master-is-not-responsive-on-startup/139651 "2026-09-25T20:37:41Z")

</div>

For some time now, I’ve been noticing that both Julia master (compiled locally) and Julia nightly do not respond to key strokes when I run the Julia binary (with or without --startup-file=no). Once I press Ctrl-C, the pr…

---

## [Prospective changes to AnnotatedString and StyledStrings](https://discourse.julialang.org/t/prospective-changes-to-annotatedstring-and-styledstrings/134847)

<div class="topic-metadata">

**Author:** [@tecosaur](https://discourse.julialang.org/u/tecosaur)\
**Replies:** 22\
**Last updated:** [September 21, 2026, 5:46pm UTC](https://discourse.julialang.org/t/prospective-changes-to-annotatedstring-and-styledstrings/134847 "2026-09-21T17:46:56Z")

</div>

A request for feedback and testing for a large piece of work I’ve undertaken Background The StyledStrings was first conceptualised in June 2021, PR’d in May 2023, merged in Oct 2023, and shipped in Julia v1.11. Since t…

---

## [JuliaSyntax.jl vs flisp julia-parser](https://discourse.julialang.org/t/juliasyntax-jl-vs-flisp-julia-parser/139554)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [September 18, 2026, 5:51pm UTC](https://discourse.julialang.org/t/juliasyntax-jl-vs-flisp-julia-parser/139554 "2026-09-18T17:51:54Z")

</div>

JuliaSyntax.jl not mentioned, and “constructed by julia-parser.scm” is outdated? It’s no longer used right, at least by default? There is another document mentioning both. I think I could clarify this document, I want …

---

## [New syntax for function decoration with macros](https://discourse.julialang.org/t/new-syntax-for-function-decoration-with-macros/139512)

<div class="topic-metadata">

**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 2\
**Last updated:** [September 17, 2026, 10:40am UTC](https://discourse.julialang.org/t/new-syntax-for-function-decoration-with-macros/139512 "2026-09-17T10:40:31Z")

</div>

I have noticed, that the Base functions now use a new syntax, where the decorator macros such as @inline or @propagate\_inbounds appear as the first line of the body of the function. What version of Julia was this synta…

---

## [Compiled application startup time under 10ms for 368MB sysimage](https://discourse.julialang.org/t/compiled-application-startup-time-under-10ms-for-368mb-sysimage/139313)

<div class="topic-metadata">

**Author:** [@melevy](https://discourse.julialang.org/u/melevy)\
**Replies:** 0\
**Last updated:** [September 9, 2026, 3:14pm UTC](https://discourse.julialang.org/t/compiled-application-startup-time-under-10ms-for-368mb-sysimage/139313 "2026-09-09T15:14:08Z")

</div>

I build compiled binaries for a network simulator and the process startup time really bugged me. Investigation showed that it is not really inherent to the problem. The image is mmapped fine, but then the loader walks tw…

---

## [Why open-source timelines/roadmaps don't work](https://discourse.julialang.org/t/why-open-source-timelines-roadmaps-dont-work/99518)

<div class="topic-metadata">

**Author:** [@tim.holy](https://discourse.julialang.org/u/tim.holy)\
**Replies:** 41\
**Last updated:** [September 7, 2026, 6:48pm UTC](https://discourse.julialang.org/t/why-open-source-timelines-roadmaps-dont-work/99518 "2026-09-07T18:48:09Z")

</div>

In my time working on Julia, I’ve seen a lot of requests for estimates of when some feature will be finished, or a roadmap for how it’s going to be accomplished. This post is intended to summarize why satisfying these re…

---

## [Pretty sure this is a severe compiler bug breaking typeof via just a simple parametrized type](https://discourse.julialang.org/t/pretty-sure-this-is-a-severe-compiler-bug-breaking-typeof-via-just-a-simple-parametrized-type/139145)

<div class="topic-metadata">

**Author:** [@skraemer](https://discourse.julialang.org/u/skraemer)\
**Replies:** 17\
**Last updated:** [September 6, 2026, 1:44pm UTC](https://discourse.julialang.org/t/pretty-sure-this-is-a-severe-compiler-bug-breaking-typeof-via-just-a-simple-parametrized-type/139145 "2026-09-06T13:44:47Z")

</div>

The following short code yields an incorrect false (in both v1.12.6/7) from a typeof call, or respectively, typeof(x) changes during runtime even though x does not. Short version struct PT{X} field::X PT(x::X)…

---

## [Security of Julia, since possible to change the compiler at runtime](https://discourse.julialang.org/t/security-of-julia-since-possible-to-change-the-compiler-at-runtime/139199)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 3\
**Last updated:** [September 4, 2026, 1:29pm UTC](https://discourse.julialang.org/t/security-of-julia-since-possible-to-change-the-compiler-at-runtime/139199 "2026-09-04T13:29:00Z")

</div>

Continuing the discussion from This month in Julia World - 2026-08: Slide 48 Not too surprising. If you have access to the compiler (or infrastructure), then you can change the generated code: We can already change …

---

## [Why does base not include Float128?](https://discourse.julialang.org/t/why-does-base-not-include-float128/139092)

<div class="topic-metadata">

**Author:** [@rokke](https://discourse.julialang.org/u/rokke)\
**Replies:** 3\
**Last updated:** [August 29, 2026, 12:38am UTC](https://discourse.julialang.org/t/why-does-base-not-include-float128/139092 "2026-08-29T00:38:55Z")

</div>

I always thought it was weird that Base supports Float16 but doesn’t include Float128, even though IEE754 considers quads a basic format, while half is just an interchange format: the other benefit of including 128 in…

---

## [Precompilation and trimming a discrete event simulator for communication networks](https://discourse.julialang.org/t/precompilation-and-trimming-a-discrete-event-simulator-for-communication-networks/139010)

<div class="topic-metadata">

**Author:** [@melevy](https://discourse.julialang.org/u/melevy)\
**Replies:** 7\
**Last updated:** [August 24, 2026, 9:46pm UTC](https://discourse.julialang.org/t/precompilation-and-trimming-a-discrete-event-simulator-for-communication-networks/139010 "2026-08-24T21:46:47Z")

</div>

Hi! I’m new here and maybe I’m not doing it the right way, if so I’m sorry for my ignorance. So I’m interested in precompiling and trimming a Julia program to decrease the startup time and avoid compilation during exec…

---

## [Manual control of overloading existing methods](https://discourse.julialang.org/t/manual-control-of-overloading-existing-methods/133836)

<div class="topic-metadata">

**Author:** [@frankwswang](https://discourse.julialang.org/u/frankwswang)\
**Replies:** 19\
**Last updated:** [August 15, 2026, 5:19pm UTC](https://discourse.julialang.org/t/manual-control-of-overloading-existing-methods/133836 "2026-08-15T17:19:25Z")

</div>

I am curious to know how much people want to have a feature/mechanism in Julia to manually control function overloading. Specifically, to disallow overloading already defined methods when intended. One direct motivation…

---

## [Pkg.resolve() fails](https://discourse.julialang.org/t/pkg-resolve-fails/138702)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 10\
**Last updated:** [August 10, 2026, 9:02am UTC](https://discourse.julialang.org/t/pkg-resolve-fails/138702 "2026-08-10T09:02:47Z")

</div>

It is not clear to me how resolve is supposed to work. Scenario: I have a package A it depends on package B There is a new version of package B In package A I increase the compat entry of package B to the new versio…

---

## [Is the development of 1.13 stuck?](https://discourse.julialang.org/t/is-the-development-of-1-13-stuck/138693)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 4\
**Last updated:** [August 8, 2026, 8:58pm UTC](https://discourse.julialang.org/t/is-the-development-of-1-13-stuck/138693 "2026-08-08T20:58:09Z")

</div>

The same three open issues for more than two weeks: OK, it is summer, and everyone is on holiday. But I thought in the US you don’t have as many holidays as in Europe. Are there any blockers?

---

## [Up requirement from 2.6.24+ to Linux 4.18 - for restartable sequences?](https://discourse.julialang.org/t/up-requirement-from-2-6-24-to-linux-4-18-for-restartable-sequences/138685)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [August 8, 2026, 2:09pm UTC](https://discourse.julialang.org/t/up-requirement-from-2-6-24-to-linux-4-18-for-restartable-sequences/138685 "2026-08-08T14:09:51Z")

</div>

Linux kernel 4.18 was officially released on August 12, 2018, already 8 years old EDIT: that was 4.8: October 2, 2016, soon a decade old, but the 4.18 Linux kernel, and older, are EOLed anyway already. After this year 6.…

---

## [Phasing out Julia support for 32-bit Windows](https://discourse.julialang.org/t/phasing-out-julia-support-for-32-bit-windows/137912)

<div class="topic-metadata">

**Author:** [@dilumaluthge](https://discourse.julialang.org/u/dilumaluthge)\
**Replies:** 3\
**Last updated:** [August 6, 2026, 12:57am UTC](https://discourse.julialang.org/t/phasing-out-julia-support-for-32-bit-windows/137912 "2026-08-06T00:57:17Z")

</div>

Currently, we use the msys2 toolchain to build Julia for Windows. Unfortunately, msys2 has stopped supporting 32-bit Windows, and they are in the process of removing all of their 32-bit Windows packages. This means that …

[Next page](https://discourse.julialang.org/c/dev/5.md?no_subcategories=false&page=1)