Why can '=' not be overloaded in C#?

Question

I was wondering, why can\'t I overload \'=\' in C#? Can I get a better explanation?

Answer 1

Being able to define special semantics for assignment operations would be useful, but only if such semantics could be applied to all situations where one storage location of a given type was copied to another. Although standard C++ implements such assignment rules, it has the luxury of requiring that all types be defined at compile time. Things get much more complicated when Reflection and and generics are added to the list.

Presently, the rules in .net specify that a storage location may be set to the default value for its type--regardless of what that type is--by zeroing out all the bytes. They further specify that any storage location can be copied to another of the same type by copying all the bytes. These rules apply to all types, including generics. Given two variables of type KeyValuePair, the system can copy one to another without having to know anything but the size and alignment requirements of that type. If it were possible for t1, t2, or the type of any field within either of those types, to implement a copy constructor, code which copied one struct instance to another would have to be much more complicated.

That's not to say that such an ability offer some significant benefits--it's possible that, were a new framework being designed, the benefits of custom value assignment operators and default constructors would exceed the costs. The costs of implementation, however, would be substantial in a new framework, and likely insurmountable for an existing one.