[Haskell-cafe] Overlapping instances with "instance F a => G a"

Brandon Allbery allbery.b at gmail.com
Thu Jan 1 22:15:31 UTC 2015

On Thu, Jan 1, 2015 at 4:29 PM, Bryan Gardiner <bog at khumba.net> wrote:

> Doesn't "HostBinaryNum a => HostBinary a" create a HostBinary instance
> for all instances of HostBinaryNum only?  So why would it cause

No, it creates an instance for all types, then checks for HostBinaryNum at
the point where it tries to use the instance.

brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
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