# Provide an option to require explicit \`var\` declarations

**URL:** <https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207>\
**Category:** Mojo 1.0 Beta\
**Tags:** discussion\
**Created:** [June 7, 2026, 6:22am UTC](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207 "2026-06-07T06:22:57Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![christoph\_schlumpf](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/christoph_schlumpf/32/274_2.png) [@christoph\_schlumpf](https://forum.modular.com/u/christoph_schlumpf)\
**Post date:** [July 6, 2026, 10:56am UTC](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207/21 "2026-07-06T10:56:02Z")

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I think the main "friction“ here is the mixture of “explicit block-scoped” and “implicit function-scoped” declarations in Mojo functions. This adds some complexity to the language. Having just one declaration style would make Mojo less complex and easier to read and understand.

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**Author:** ![christoph\_schlumpf](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/christoph_schlumpf/32/274_2.png) [@christoph\_schlumpf](https://forum.modular.com/u/christoph_schlumpf)\
**Post date:** [July 28, 2026, 4:50am UTC](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207/22 "2026-07-28T04:50:02Z")

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FYI 🔥:

> [@Requiring \`var\` for variable declarations](https://forum.modular.com/t/requiring-var-for-variable-declarations/3351):
>
> We’re making a fairly major change in Mojo syntax leading up to 1.0: var will now be required before new variable declarations. Previously, you could declare a new variable either through the use of an explicit var variable = ... or through variable = .... We will start warning about the use of the latter in the next nightly, and then make it an error to use that syntax before 1.0. The two ways of declaring a new variable in Mojo have been the subject of [lengthy](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207) [prior discussions](https://forum.modular.com/t/def-fn-and-var/90) and we know th…

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**Author:** ![jbemmel](https://avatars.discourse-cdn.com/v4/letter/j/5daacb/32.png) [@jbemmel](https://forum.modular.com/u/jbemmel)\
**Post date:** [July 29, 2026, 8:45pm UTC](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207/23 "2026-07-29T20:45:17Z")

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May I suggest to update the Mojo skills to proactively include this change, if not already done?

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**Author:** ![BradLarson](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/bradlarson/32/62_2.png) [@BradLarson](https://forum.modular.com/u/BradLarson)\
**Post date:** [July 30, 2026, 4:03pm UTC](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207/24 "2026-07-30T16:03:35Z")

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Great suggestion, we’ll try to call this out in there.

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**Author:** ![dunnoconnor](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/dunnoconnor/32/1093_2.png) [@dunnoconnor](https://forum.modular.com/u/dunnoconnor)\
**Post date:** [July 31, 2026, 4:16pm UTC](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207/25 "2026-07-31T16:16:02Z")

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Just pushed an update to the skills that will go out with the next release

[Previous page](https://forum.modular.com/t/provide-an-option-to-require-explicit-var-declarations/3207.md?page=1)