On Mon, Aug 3, 2015 at 12:45 PM, Daniel Bergey <bergey@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.

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