On Mon, Mar 9, 2015 at 10:33 PM, Rustom Mody <rustompmody@gmail.com> wrote:
My impression is that earlier
[] == []
used to give a type error.  Now it gives True.

So
1. Which instance of == is being used?
2. Is there some option controlling this behavior?

The instance being used is (), and it's controlled by -XExtendedDefaultRules.
https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/interactive-evaluation.html#extended-default-rules

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