Polysemous Values Qustion

[Nathan Reed]

Robert Frser wrote:
> Can someone giv me an example where polysemous values could apply to a class (given the class has (multiple) opImplicitCastTo/From)

Here's another example where polysemous values could come in handy:

interface A { ... }
interface B { ... }

class Foo : A, B { ... }
class Bar : A, B { ... }

void main (string[] args)
{
     bool flag = ...
     auto whatsMyType = flag ? new Foo : new Bar;
}

Here, Foo and Bar both implement A and B, so the variable 'whatsMyType' 
could have either type A or type B.  If you do this in D now, it will 
fail with a compile error, since Foo and Bar have no least upper 
bound...but with polysemous values, whatsMyType could have type "A or B".

Thanks,
Nathan Reed