Can we just have struct inheritence already?

[XavierAP]

On Friday, 14 June 2019 at 14:47:15 UTC, XavierAP wrote:
> On Thursday, 13 June 2019 at 22:13:51 UTC, Manu wrote:
>>
>> So don't implicitly convert to the base type?
>> B extends A, but I don't think it's a kind of A as for 
>> polymorphic classes.
>
> Less typing is good but stuff happening magically/unexpectedly 
> for a neutral reader of the code (e.g. implicit casts) is not. 
> And if on the other hand, !is(B:A), then what is the advantage, 
> and the use case?

Moreover, even if your inheritance did not produce (static) 
polymorphism in the hard sense i.e. !is(B:A), it would in the 
duck-typed sense, in templates! So inheritance without 
polymorphism is inconsistent.

	struct A { void fun(); };
	struct B :A {};
	
	void gun(A x)    { x.fun; }
	void hun(T)(T x) { x.fun; }
	
	B b;
	b.gun; // error?
	b.hun; // ok