Comment 7 for bug 1051847

Hello Simone

As I wrote, I'm trying to infer the correct behavior of Contains from the current documentation.
As Contains is now documented as identity assertion, yes, I expect it should check identity equality.

I guess that if it was implemented like this, this bug would disappear.

Whether Contains does identity or equality checking is a design decision. Apparently, equality checking is more difficult to do.

The implementation now seems to perform equality checking, where the documentation indicates it should do identity checking. If the final resolution was to stick with equality checking, I'd expect Contains to be documented in the equality asserts section, no longer in the identity asserts section.

Checking for identity is easier to implement. But doing so is a breaking change. So I cannot give a final suggestion.