On 16.07.2017 21:49, Guillaume Boucher wrote:
I'd say a function with return type Bottom can override any function
in the base class.
That solves the "Penguin : Bird" step, but not "EvolvedPenguin :
Penguin" (which can fly).
Andrei argues that my example don't comply with a puristic understanding
of inheritance. Maybe that's enough of a reason to not optimize such
use cases, but it still shows that pragma(noreturn) is somehow stronger
than Bottom.
The issue isn't purism, it is type safety. If you create an
EvolvedPenguin, upcast it to a Penguin and call the fly method you get
UB. So noreturn would indeed need to enforce that all overrides are also
noreturn.
