[Haskell-cafe] Any precedent or plan for guaranteed-safe Eq and Ord instances?

[Roman Cheplyaka]

* Stijn van Drongelen <rhymoid at gmail.com> [2013-10-02 15:46:42+0200]
> I do think something has to be done to have an Eq and Ord with more strict
> laws.
> 
> * Operators in Eq and Ord diverge iff any of their parameters are bottom.

This outlaws the Eq instances of lists, trees, and other (co)recursive
types.

Furthermore, in this formulation, even Eq for tuples is illegal, because

  (undefined, something) == somethingElse

is going to diverge.

Roman
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