# Idea: Extensible Union types and benefits they bring for real world Elm code

**URL:** <https://discourse.elm-lang.org/t/idea-extensible-union-types-and-benefits-they-bring-for-real-world-elm-code/6118>\
**Category:** Request Feedback\
**Created:** [August 3, 2020, 3:57am UTC](https://discourse.elm-lang.org/t/idea-extensible-union-types-and-benefits-they-bring-for-real-world-elm-code/6118 "2020-08-03T03:57:20Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![bob-shelline](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.elm-lang.org/bob-shelline/32/465_2.png) [@bob-shelline](https://discourse.elm-lang.org/u/bob-shelline)\
**Post date:** [August 3, 2020, 9:27pm UTC](https://discourse.elm-lang.org/t/idea-extensible-union-types-and-benefits-they-bring-for-real-world-elm-code/6118/5 "2020-08-03T21:27:08Z")

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This puts into words the discomfort with “Msg” types that I’ve run up against time and time again as I take on increasingly complex Elm apps. I think what really resonates with me is how you address the problem we have trying to follow the instructions in the [Structure](https://guide.elm-lang.org/webapps/structure.html) section of the Elm guide. I love those guidelines, but have found them impossible to follow with our current tools, and I think you’ve hit it on the head with extensible union types filling that gap.

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