Containers

[Kagamin]

On Wednesday, 1 September 2021 at 12:32:36 UTC, Steven 
Schveighoffer wrote:
> To further explain for readers, the issue is:
>
> ```d
> void foo(T)(Vector!(const(T)) arg);
> ```

This compiles:
```d
struct Vector(T){}
void f(T:const(U),U)(Vector!T arg);
void f1()
{
     Vector!(const int) a;
     f(a);
}
```