False positive error CS9503 "Required member cannot be less visible than the containing type" for member in nested type

[sirduke]

Version Used:
features/required-members

Steps to Reproduce:

internal class InternalOuterCsass
{
    public  class PublicInnerClass
    {
        internal required int field;
    }
}

Expected Behavior:
no error because effective accessibility of containing type is "internal"

Actual Behavior:

error CS9503: Required member 'InternalOuterCsass.PublicInnerClass.field' cannot be less visible or have a setter less visible than the containing type

[jcouv]

I'm failing to see what the error protects in this scenario. We might consider tweaking the rules a bit.

[333fred]

IMO, this is pretty analogous to how interface methods must be public in such a scenario, even though PublicInnerClass is effectively internal.

[333fred]

It turned out to be easier to fix #61528 by specifying in terms of effective visibility, which changes the behavior in this bug as requested.