The code in `tagged` has been generalized for a couple of years now, but Data.Proxy either forked off of it before we made that generalization or simply didn't get the more generalized type when it was moved into base. I'm strongly +1 on this generalization for consistency with the tagged package and with the other combinators already in base. -Edward On Sun, Nov 6, 2016 at 2:31 PM, David Feuer wrote:

I think flexibility about the proxy type has become the norm, and we should probably follow that guideline. However, it could theoretically break code.

asProxyTypeOf x (pure "I'm a string")

is currently accepted but would be rejected with the proposed change (since the proxy type isn't fixed, GHC doesn't know that it's Applicative).

On Nov 6, 2016 12:37 PM, "Tom Ellis" wrote:

...

Did anything ever come of this proposal to relax the type of asProxyType of?

https://mail.haskell.org/pipermail/libraries/2014-December/ 024462.html

i.e. change

asProxyTypeOf :: a -> Proxy a -> a

to

asProxyTypeOf :: a -> proxy a -> a

I posted this issue on the Trac

https://ghc.haskell.org/trac/ghc/ticket/12805

but it was suggested I ask on the libraries list.

Tom _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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