Typechecker / OverloadedStrings question 7.8 vs. 7.10

[Brandon Allbery]

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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