Suppose I have a base class where one of the methods has an in-contract, and a
derived class that overrides it:
/////////////////////////////////////////
import std.stdio;
abstract class Base
{
abstract void foo(int n)
in
{
assert(n > 5);
}
body
{
assert(false, "Shouldn't get here");
}
}
class Deriv : Base
{
override void foo(int n)
{
writeln("n = ", n);
}
}
void main()
{
Base b = new Deriv;
b.foo(7);
b.foo(3);
}
/////////////////////////////////////////
This outputs,
n = 7
n = 3
In other words, the lack of explicit in-contract on Deriv.foo is being taken as
an _empty_ in-contract, which is being interpreted as per the rule that a
derived class can have a less restrictive contract than its base (cf. TDPL
pp.329-331).
Question: is there any way of indicating that Deriv.foo should inherit the
in-contract from the base method, without actually calling super.foo ... ?
Following the example on p.331, I did try calling super.__in_contract_format(n)
(... or this.Base.__in_contract_format(n) or other variants), but that doesn't
seem to work:
Error: no property '__in_contract_foo' for type 'incontract.Base'
... so can anyone advise if there is a reasonable way of achieving this?
Thanks,
-- Joe
