[Haskell-cafe] Applying typed hole proposal leads to compilation failure

mniip 14 at mniip.com
Sat Aug 25 10:43:07 UTC 2018

On Fri, Aug 24, 2018 at 06:25:34PM -0400, Brandon Allbery wrote:
> Note that this also requires ScopedTypeVariables; the Haskell standard
> specifies that type variables are only in scope within the type signature,
> not the accompanying binding. Which is also why the explicit "forall" is
> required, to tell it to use the modified rules here, which otherwise could
> cause other code that expects standard Haskell behavior to fail to compile
> if it happens to reuse type variables from the signature.

I had thought of mentioning this but their original snippet included the
extension so I thought they already knew.

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