Typechecker / OverloadedStrings question 7.8 vs. 7.10

Brandon Allbery allbery.b at gmail.com
Mon Aug 3 16:47:44 UTC 2015

On Mon, Aug 3, 2015 at 12:45 PM, Daniel Bergey <bergey at teallabs.org> wrote:

> I thought GHC would infer the type when only one instance is in scope,
> at least in some cases, like IsString.  But I could well be wrong about
> that.

Typeclasses are open-world; this is not a safe assumption, since instances
are global and an instance added elsewhere at some point in the future
could therefore break your program.

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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