Language extension histories

Takenobu Tani takenobu.hs at
Sun Nov 1 01:34:50 UTC 2020


Maybe the next page is what you want? :

PatternSynonyms was implemented in GHC 7.8, and TypeFamilyDependencies
was implemented in GHC 8.0.


On Sun, Nov 1, 2020 at 2:08 AM David Feuer <david.feuer at> wrote:
> I'm working on some code I want to be compatible with multiple GHC versions and I'm trying to figure out which language extensions I can reasonably use. I definitely need usable fancy pattern synonyms (not the bare-bones ones in 7.8). So that should set a lower bound, but I don't remember where. 7.10? 8.0? I'd also *like* to use an injective type family, but I can work around that pretty easily with a data family if necessary. When did PatternSynonyms and TypeFamilyDependencies each become reasonably usable?
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