[Haskell-cafe] Is using Data.Dynamic considered a no-go?

[Don Stewart]

bugfact:
> Haskell seems to have pretty strong support for dynamic casting using
> Data.Typeable and Data.Dynamic.
> 
> All kinds of funky dynamic programming seems to be possible with these
> "hacks". 
> 
> Is this considered as being as bad as - say - unsafePerformIO? What kind of
> evil is lurking here?

Inefficiencies and runtime errors?

-- Don