System.TimeZoneInfo.AdjustmentRule is missing object.Equals(object) override

[ViktorHofer]

Applies to both netfx and corefx.

Netfx: https://referencesource.microsoft.com/#mscorlib/system/timezoneinfo.cs,3066
Core: https://github.com/dotnet/coreclr/blob/master/src/mscorlib/src/System/TimeZoneInfo.AdjustmentRule.cs#L46

Repro

var a = TimeZoneInfo.AdjustmentRule.CreateAdjustmentRule(new DateTime(1900, 1, 1), 
    new DateTime(1955, 12, 31),
    TimeSpan.FromHours(2), 
    TimeZoneInfo.TransitionTime.CreateFixedDateRule(new DateTime(1, 1, 1, 2, 0, 0), 2, 3), 
    TimeZoneInfo.TransitionTime.CreateFixedDateRule(new DateTime(1, 1, 1, 2, 0, 0), 3, 4));

var b = TimeZoneInfo.AdjustmentRule.CreateAdjustmentRule(new DateTime(1900, 1, 1), 
    new DateTime(1955, 12, 31),
    TimeSpan.FromHours(2), 
    TimeZoneInfo.TransitionTime.CreateFixedDateRule(new DateTime(1, 1, 1, 2, 0, 0), 2, 3), 
    TimeZoneInfo.TransitionTime.CreateFixedDateRule(new DateTime(1, 1, 1, 2, 0, 0), 3, 4));

Console.WriteLine("ReferenceEquals: " + ReferenceEquals(a, b)); // false
Console.WriteLine("a == null: " + (a == null)); // false
Console.WriteLine("b == null: " + (b == null)); // false
Console.WriteLine("a == b: " + (a == b)); // false
Console.WriteLine("a.equals(b): " + a.Equals(b)); // true
Console.WriteLine("Object.Equals: " + Object.Equals(a, b)); // false

cc @danmosemsft

[ViktorHofer]

cc @stephentoub

[stephentoub]

@tarekgh?

[tarekgh]

I think this will apply to many types and not just AdjustmentRule. I would hesitate to change anything in TZ in general before we figure out the plans for the other requests. there is a possibility we deprecate AdjustmentRule for the sake more fixable way in handling TZ and its rules.