partially applied type synonyms

Herbert Valerio Riedel hvr at
Mon Mar 5 12:55:16 CET 2012

Arie Peterson writes:

> Is there a good reason that partially applied type synonyms cannot be made
> instances of classes?


> Partially applied type synonyms are, in a sense, the anonymous functions
> at the type level, and one might argue that they deserve the same
> 'first-class member status' as the lambda at the value level.

According to SPJ, the problem seems to be requiring higher-order
unification for this to happen:

Does anyone here know (as SPJ's response is quite a few years old) if
there's been made any progress since back then?


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