I think that a lot of those bugs can be explained as an incomplete understanding of variance for many people: it's really hard to get your head around it!
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Any reason why ppl prefer not to use variance? I thought it would always provide benefit of relaxing type hierarchy restrictions, which would be something desired in fp libs
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It's a trade-off between several constraints. Invariance is easier at the definition-site, but has a cost at every use-site. But I have too much to say about this to put into a tweet... ;)
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It is unexpectedly expressive even in the absence of any subtyping.
Thanks. Twitter will use this to make your timeline better. UndoUndo
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