Operator "==" not working when the attributed class is in the same assembly as call site

[imacek]

Hi, it seems to me that the Fody generated operator "==" is not working when the attributed class with [Equals] is in the same assembly as call site.

I've done a runnable example which demonstrates the issue: https://github.com/IvanMacek/FodyEqualsFailExample

Call to the Equals method works as expected.
When the class is implemented in the another assembly operator "==" works as expected.

Thank you for your time!

Cheers,
Ivan

[SimonCropp]

i am not likely to get to this one. any chance of a PR?

[rjasica]

I thought about this. C# compiler do not emit call to operator==, so it is not easy to implement. It have to guest type on stack to replace normal compare operation. Any other idea?

Workaround: add empty operators to class, but is not beautiful solution...

[SimonCropp]

@rjasica if this cant be fixed should a compile time exception be thrown to explain it is not a supported scenario?

[SimonCropp]

@rjasica thoughts?

[rjasica]

My only idea: generatig operators require passing some parameter to Equals attribute. In this case if empty operators are not created, exception will be throw.

[SimonCropp]

@rjasica still working on this? @IvanMacek any chance you want to try for a PR?

[imacek]

@SimonCropp sorry I don't have an active project using Fody anymore so I don't have time to play with this :(

[mikhailshilkov]

Do you guys have an example of a workaround?

[rjasica]

Sorry for inconvenience, but it is not easy to implement this feature.

Workaround: Move type to new/other assembly.

[SimonCropp]

@rjasica so what do we do with this one? Close as not possible to fix?

[markusamshove]

Hi guys,

I just stumbled over this (after not being able to figure out what the problem was :) ).

Is there any chance this might be supported in the future?

The following workaround is working btw:

[Equals(DoNotAddEqualityOperators =true)]
public class Point
{
    ...

    public static operator==(Point left, Point right) => left.Equals(right);
    public static operator!=(Point left, Point right) => !left.Equals(right);
}

[mutzl]

What a bummer!
This is really, really dangerous.
Even analyzing the decompiled class containing the [Equals] attribute will not point to the issue, because the issue is hidden in the usage of the operator by this unwanted cast to (object).

return (object)a == (object)b;
instead of
return a == b;

So I suggest, making the default of DoNotAddEqualityOperators = true;
(Which is of course a breaking change.)

Nevertheless: there needs to be a highlyvisible warning on the first page about this unpredictable behaviour.
(I personally lost a day due to this.)

[ivorco]

How can the developer not fixed it yet?