# A possible change for Julia 2.0: per-argument mutation ! marks?

**URL:** <https://discourse.julialang.org/t/a-possible-change-for-julia-2-0-per-argument-mutation-marks/119631>\
**Category:** Internals & Design\
**Created:** [September 20, 2024, 12:26am UTC](https://discourse.julialang.org/t/a-possible-change-for-julia-2-0-per-argument-mutation-marks/119631 "2024-09-20T00:26:34Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [September 20, 2024, 12:30am UTC](https://discourse.julialang.org/t/a-possible-change-for-julia-2-0-per-argument-mutation-marks/119631/2 "2024-09-20T00:30:45Z")

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> [@xiaodai](#):
>
> `function change(!a, b)` is a function that mutates `a` and must be called by `change(!a, b)`

That would be such an enormous change to how the language works that I think this applies: [PSA: Julia is not at that stage of development anymore](https://discourse.julialang.org/t/psa-julia-is-not-at-that-stage-of-development-anymore/44872)

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