Annoyance with function template unwrapping

[Paul Backus]

On Sunday, 17 January 2021 at 18:36:13 UTC, kdevel wrote:
>
> It's odd behavior. It seems that in D template definitions are 
> things
> in itself (like a struct definition) which obey a one 
> declaration (!) rule.

It's not exactly a one-declaration rule. Templates, like 
functions, can be overloaded:

template foo(T) {
     enum foo = "overload one";
}

template foo(T, U) {
     enum foo = "overload two";
}

static assert(foo!int == "overload one");
static assert(foo!(int, double) == "overload two");

As long as the overloads are unambiguous, there's no problem. As 
with functions, it's only when you have two overloads that match 
the same arguments that you get an error.