D is fine with alias this overloaded function:
---
void foo(int t) {}
void foo(int t, int i) {}

alias bar = foo;
---

But isn't as happy aliasing these function templates:
---
void foo(T)(T t) {}
void foo(T)(T t, int i) {}

alias bar = foo!int;
---

Is there some way/other syntax to make an alias like this work? Or specify in the alias which function template to use (ie. alias bar = foo!int(int)).

On Tuesday, 11 November 2014 at 19:36:12 UTC, Lemonfiend wrote:
> D is fine with alias this overloaded function:
> ---
> void foo(int t) {}
> void foo(int t, int i) {}
>
> alias bar = foo;
> ---
>
> But isn't as happy aliasing these function templates:
> ---
> void foo(T)(T t) {}
> void foo(T)(T t, int i) {}
>
> alias bar = foo!int;
> ---
>
> Is there some way/other syntax to make an alias like this work? Or specify in the alias which function template to use (ie. alias bar = foo!int(int)).

The problem is not the alias. The error message is about using the same identifier for two different things:

> C:\...\temp_0186F968.d(13,1): Error: declaration foo(T)(T t, int i) is already defined.

1/ ===================================================

What you seem to forget is that the declarations:
---------------------
void foo(T)(T t) {}
void foo(T)(T t, int i) {}
---------------------
are actually a two **Eponymous template** with the same name:
---------------------
template foo(T){
    void foo(T t) {}
}
template foo(T){
    void foo(T t, int i) {}
}
---------------------
This produces the same error message:
> C:\...\temp_0186F968.d(13,1): Error: declaration foo(T)(T t, int i) is already defined.

2/ ===================================================

You can make it working by renaming the template name anf by grouping the members:
---------------------
template hip(T)
{
    void bud(T t) {}
    void bud(T t, int i) {}
}

alias baz = hip!int.bud;
writeln(typeof(baz).stringof);
// > void(int t) or void(int t, int i) if you invert bud order.
---------------------

> The problem is not the alias. The error message is about using the same identifier for two different things:
>
>> C:\...\temp_0186F968.d(13,1): Error: declaration foo(T)(T t, int i) is already defined.
I'm not sure what is giving you that particular error. Without the alias it compiles and runs fine for me.

When I wrap them individually in the template statement, it gives:
---
src\app.d(24): Error: template app.foo cannot deduce function from argument types !()(int), candidates are:
src\app.d(40):        app.foo(T)
src\app.d(45):        app.foo(T)
---

When I wrap them together, I can indeed alias it, thanks!

> What you seem to forget is that the declarations:
> ---------------------
> void foo(T)(T t) {}
> void foo(T)(T t, int i) {}
> ---------------------
> are actually a two **Eponymous template** with the same name:
> ---------------------
> template foo(T){
>     void foo(T t) {}
> }
> template foo(T){
>     void foo(T t, int i) {}
> }
> ---------------------
Yes I had forgotten, assuming I ever knew :)