What languages support covariance on inherited methods' return types?

Question

I originally asked this question , but in finding an answer, discovered that my original problem was a lack of support in C# for covariance on inherited methods' return types. After discovering that, I became curious as to what languages do support this feature.

I will accept the answer of whoever can name the most.

EDIT : John Millikin correctly pointed out that lots of dynamic languages support this. To clarify:

I am only looking for static/strongly typed languages.

Answer 1

• C++
• Java
• REALbasic
• Eiffel
• Sather
• Modula-3

Answer 2

任何动态语言，当然 - Python，Ruby，Smalltalk，Javascript等。

Answer 3

Basically what I'm asking is what languages support what I'm trying to do here.

Does C# let you specify different data types for the get() and set() methods? If not, I would split them into actual Leg get_leg() and set_leg(DogLeg) functions. Otherwise one of two things will happen: 1) overspecification of get_leg() 2) underspecification of set_leg() .

Answer 4

C ++支持协变返回类型。

Answer 5

Java added support for this in 1.5. It will not compile in earlier versions.

Answer 6

As pointed out by Ivan Hamilton and Mat Noguchi, C++ supports the feature. But note that covariant return types are broken for template classes which inherit from some base in MSVC 7.X through 9.X (and probably 6 also). You get error C2555.

Answer 7

but I think thats what I'm asking for..or is it?

I frankly don't know what you're asking. Java apparently has the same support for return-type covariance as C#, so if whatever you're looking for is lacking in C#, it's lacking in Java also.