Annoyance with function template unwrapping

[kdevel]

On Saturday, 16 January 2021 at 22:09:48 UTC, solidstate1991 
wrote:

[...]

> However defining the function templates this way works:
>
> template func(ubyte b) {
>     void func(int i) {
>         writeln(__PRETTY_FUNCTION__);
>     }
>     void func(float i) {
>         writeln(__PRETTY_FUNCTION__);
>     }
> }

Fits.

> I might change my project CPUblit to fit to the latter, and 
> then add unittests to ensure that it works, but I don't know 
> whether it's a bug, some odd behavior, or something DIP-worthy.

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.

    template S (T) {
       void foo () {}
    }
    template S (T) {
       void bar () {}
    }

    auto fp = &S!int.bar;

depicts the programmer's intent in a crystal clear manner. 
Nonetheless dmd
yiels the error you encountered. I think that D-templates should 
behave like
C++ namespaces not like structs.