# [Agda] Type decidability

Daniel Peebles pumpkingod at gmail.com
Mon Jan 21 20:01:15 CET 2013

I'm pretty sure it shouldn't be possible to do that in Idris (if it is,
it's probably a bug), and I don't think most people want it in Agda either.
The main reason it's undesriable is that it violates parametricity, which
is a property most FP people really want.

On Mon, Jan 21, 2013 at 12:58 PM, Dmytro Starosud <d.starosud at gmail.com>wrote:

> Hello guys,
>
> In Idris one can write:
>
> g : Type -> Bool
> g Int = True
> g _ = False
>
> Is it possible to do the same in Agda, in particular:
>
> type-dec : (A B : Set) -> Dec (A \equiv B)
> type-dec = ?
>
>
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>
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