Templates convariance

[Sean Fritz]

In article <e799ce$2idm$1 at digitaldaemon.com>, michal.minich at gmail.com says...

A list!(Shape) is not the same a a list!(Square).  It sounds like you want some
sort of wildcard matching or something to enforce type bounding like Java/C#
have, but casts are definitely unsafe.

Example code (I'm going to blotch various syntax, sorry in advance):

void foo(List!(Shape) ls) {
ls.add(new Circle) //passes type check locally?
}

..
List!(Square) ls = new List!(Square);
foo(ls);
//but ls now contains a Circle?  Circles don't go in List!(Square)?
,,.