Add `HasCallStack` constraint to `ioError`

[bgamari]

I propose that the type of ioError as exposed by Control.Exception and System.IO.Error be augmented with a HasCallStack constraint:

ioError         :: HasCallStack => IOError -> IO a

This will allow HasCallStack constraints to be propagated to exception backtraces from callsites.

Implementation: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12861

[parsonsmatt]

I'm in favor!

[Bodigrim]

Seems fairly uncontroversial to me, especially given that it's usually GHC HQ who are opposed to splashing HasCallStack around ;) Let's wait a few more days and vote.

[Bodigrim]

Dear CLC members, let's vote on the proposal to augment ioError with HasCallStack constraint. This is not a breaking change. It will allow HasCallStack constraints to propagated to exception backtraces, a new feature in GHC 9.10.

@hasufell @velveteer @tomjaguarpaw @mixphix @parsonsmatt @angerman

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+1 from me.

[mixphix]

+1

[angerman]

+1

[velveteer]

+1

[parsonsmatt]

+1

[tomjaguarpaw]

+1

[hasufell]

+1

[Bodigrim]

Thanks all, approved unanimously.