[swift-evolution] Overloading assignment operator

[Matthew Johnson]

> Here, I’d like to identity another problem: the behavior of implicit conversions can be very confusing for non-experts to reason about, and in the context of a language with a fair amount of other subtle behaviors (e.g. due to overloading), that’s a very dangerous thing to bring in.  Explicit type coercions are much easier for non-experts to reason about.

+1 to this.  I am very skeptical that the benefit of implicit conversions are worth the complexity and potential for confusion, except where a natural subtype relationship exists like Chris has mentioned in relation to numerics.