# () Enum Intstance Intentionally Throws Runtime Error

**URL:** <https://discourse.haskell.org/t/enum-intstance-intentionally-throws-runtime-error/9899>\
**Category:** Learn\
**Created:** [July 5, 2024, 3:51pm UTC](https://discourse.haskell.org/t/enum-intstance-intentionally-throws-runtime-error/9899 "2024-07-05T15:51:04Z")\
**Posts on this page:** 1\
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**Author:** ![jaror](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/jaror/32/3271_2.png) [@jaror](https://discourse.haskell.org/u/jaror)\
**Post date:** [July 5, 2024, 4:19pm UTC](https://discourse.haskell.org/t/enum-intstance-intentionally-throws-runtime-error/9899/4 "2024-07-05T16:19:17Z")

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I think `Enum` was/is primarily intended to be used through list comprehension notation. Even with that strange instance it does not go wrong, e.g. `[() .. ()]` and `[() ..]` both work fine.

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