CS0165 Use of unassigned local variable after [DoesNotReturn] method

[D0ctorWh0]

If I have method, that never return

[DoesNotReturn]
public void Exit()
{
    Environment.Exit(1);
}

than if I write this code

int? i = 0;

if(i is not int val)
{
    Exit();
}

int t = val;

the compiler shows error CS0165 "Use of unassigned local variable" on line int t = val;. But as "Exit" method never returns it should not show error. The workaround for it is to add return; after calling "Exit" method, but that not feel right...

[333fred]

See #538. The DoesNotReturnAttribute cannot give the guarantees needed to make this work.