Re: How to user-define a type equality constraint?

On Apr 1, 2021, at 8:12 PM, Anthony Clayden wrote:

Can I user-define a conventional type-class that behaves more like `(~)`?

I don't think so. But why does this matter? I can't define `Char` in user code, but it's exported from the Prelude and requires no extensions. While I can define Eq in user code, I can't make `deriving` work with my version. I can't define `error` in user code. There are many others, I'm sure. So: why does this matter? Thanks, Richard