I don’t see a difference between pass by copy and pass by value.
The mutability difference is that part of a struct can be modified in place, which value classes can’t: the value of a complete value-class variable (or array slot) can only be modified (reassigned) as a whole. This is presumably because object references to value-class objects can be created, and those objects should be immutable so their identity doesn’t matter.
The mutability difference is that part of a struct can be modified in place, which value classes can’t: the value of a complete value-class variable (or array slot) can only be modified (reassigned) as a whole. This is presumably because object references to value-class objects can be created, and those objects should be immutable so their identity doesn’t matter.