I had a bug in my code that was messing me up for a while, and it
boiled down to an identity check between two Object references
with unrelated static types, like below:
class A {}
class B {}
void main() {
A a = new A;
B b = new B;
if (a is b) {} // compiles
}
I was surprised that the type system failed me here. It's true
that A and B could be upcast to Object and then comparisons would
make sense type-wise, but the comparison should never pass (and
the compiler should know it won't since they are in separate
inheritance subtrees) unless the programmer is intentionally
breaking the type system.
Is there reasoning for this? If not, should it be a warning or
error, as it is for example when comparing two pointers to
structs of different types?
