If you want superclass instances for GHC 7.4 provide use-cases now!
haskell.org/pipermail/libraries/2011-Septembe...Posted Oct 17, 2011, 8:30 AM UTC
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haskell.org
how about the mess with number classes and containers!
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Posted Oct 17, 2011, 8:30 AM UTC
how about the mess with number classes and containers!
Isn't the Monad/Functor calamity enough motivation?
Submit it!
I get the impression he's looking for use cases that don't involve changes to the standard libraries.
Retrospectively improving the structure of widely used libraries, whilst retaining backwards compatibility with existing code, is the raison d'etre of the various superclass proposals.