Can anonymous types implement interface?

[voroninp]

I am curious whether any reasons why anonymous types do not implement interfaces.

For example, if all properties of anonymous type have types which implement IComparable, then type could implement comparison as well assuming the same order of comparisons as properties were defined with.

[KennethHoff]

#4301

[voroninp]

No, this is not the same. It's like object expression in F#

I was asking about anonymous objects, so this does not fail. Now it does:

var a = new []
{
	new { x = 1, y = -1},
	new { x = -1, y = 1}
};
a.Order().ToList();

[huoyaoyuan]

F# object expression also requires implementation of IComparable<T> to make Order work correctly.

[HaloFour]

I am curious whether any reasons why anonymous types do not implement interfaces.

Because there has been no accepted proposal to do so.

[voroninp]

Ok, at least no fundamental constraint. ;-)

[HaloFour]

No technical limitation, but there will probably be a question as to whether or not an anonymous type should automatically implement such interfaces. That's especially true given such features have been in the language for 15 years and changing their behavior now could cause subtle breaking changes to existing codebases.

Seems that tuples do implement the IComparable interfaces and should be fine in this scenario. They also have the advantage of not incurring an allocation since they are value types.