Proposal: Add Eq instance for Control.Exception.ErrorCall

[Henning Thielemann]

On Tue, 27 Nov 2012, Michael Snoyman wrote:

> +1 on the proposal. Even if I'm opposed to partial functions, I'm in 
> favor of making it easier to test them reliably.

How can you be sure that you get a certain error? Depending on the order 
of evaluation you might get different error messages if there are multiple 
possible ways to fail. I think automated testing against specific error 
messages will not work reliably.