[Haskell-cafe] Re: Is my code too complicated?

[Ertugrul Soeylemez]

Nils Schweinsberg <ml at n-sch.de> wrote:

> > This requires a bunch of type system extensions, though, most
> > notably the UndecidableInstances extension.  But it's safe to use
> > here.
>
> Probably a bit off topic, but whats wrong with UndecidableInstances?
> Where is it safe to use, when would you avoid it and what can go wrong
> here?

Essentially UndecidableInstances turns the type system into a
Turing-complete programming language.  One direct consequence is that
type checking may not terminate and, because of the halting problem, the
type system is unable to tell when that happens.


Greets,
Ertugrul


-- 
nightmare = unsafePerformIO (getWrongWife >>= sex)
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