Changes to Typeable
Christian.Maeder at dfki.de
Thu Nov 1 09:28:35 CET 2012
Am 29.10.2012 10:05, schrieb José Pedro Magalhães:
> It's been proposed to remove the possibility to derive Typeable or write
> instances for it.
> I'm supposing the way that this would be implemented would be:
> 7.8: Any uses of "deriving Typeable" would give rise to a warning saying
> that it is no longer
> necessary. Any instances of Typeable would give rise to a warning saying
> that this code
> is being ignored, and replaced by an internal Typeable instance.
> Packages might break,
> or change runtime behaviour due to this change.
> 7.10: Explicit uses of "deriving Typeable" or instances are an error.
I would vote against making "deriving Typeable" an error as this would
break a lot of existing code (and is recommended by current deprecation
Ignoring it (with or without warning) is the right thing to do (IMHO).
Furthermore there's a language flag DerivingTypeable, that should be
ignored, too, then.
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