# The Haskell Unfolder Episode 43: monomorphism restriction and defaulting

**URL:** <https://discourse.haskell.org/t/the-haskell-unfolder-episode-43-monomorphism-restriction-and-defaulting/12040>\
**Category:** Links\
**Created:** [May 7, 2025, 4:05pm UTC](https://discourse.haskell.org/t/the-haskell-unfolder-episode-43-monomorphism-restriction-and-defaulting/12040 "2025-05-07T16:05:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![kosmikus](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/kosmikus/32/372_2.png) [@kosmikus](https://discourse.haskell.org/u/kosmikus)\
**Post date:** [May 7, 2025, 4:05pm UTC](https://discourse.haskell.org/t/the-haskell-unfolder-episode-43-monomorphism-restriction-and-defaulting/12040/1 "2025-05-07T16:05:11Z")

</div>

https://www.youtube.com/embed/nD93M2qlwMk?feature=oembed&wmode=opaque&list=PLD8gywOEY4HaG5VSrKVnHxCptlJv2GAn7

Will be streamed today, 2025-05-07, at 1830 UTC, live on YouTube.

Abstract:

_In this episode, we are going to look at two interacting “features” of the Haskell language (the monomorphism restriction and defaulting) that can be somewhat surprising, in particular to newcomers: there are situations where Haskell’s type inference algorithm deliberately refuses to infer the most general type. We are going to look at a number of examples, explain what exactly is going on, and why._