You cannot specify a primitive data type for a template parameter which is defined as an alias.

Thanks to Bent Rasmussen for the simplified example case and reference to the D spec. I cut down Bent's simplified version even more. Error at the bottom.

Spec:
"Alias parameters enable templates to be parameterized with any type of D
symbol, including global names, type names, module names, template names,
and template instance names."

Test:
,----[  ]
|
| template Test(alias T) {}
| alias Test!(bit) x;
|
`----

Error:
template instance Test!(int) does not match any template declaration

Cabal wrote:
> You cannot specify a primitive data type for a template parameter which is
> defined as an alias.
> 
> Thanks to Bent Rasmussen for the simplified example case and reference to
> the D spec. I cut down Bent's simplified version even more. Error at the
> bottom.
> 
> Spec:
> "Alias parameters enable templates to be parameterized with any type of D
> symbol, including global names, type names, module names, template names,
> and template instance names."
> 
> Test:
> ,----[  ]
> | | template Test(alias T) {}
> | alias Test!(bit) x;
> | `----
> 
> Error:
> template instance Test!(int) does not match any template declaration

That's not a bug, just improper usage.
should be:
,----[  ]
|
| template Test(alias T) {}
| int x; // variable can be of any type (structs and classes included)
| alias Test!(x) aint;
|
`----

or:

,----[  ]
|
| template Test(T) {}
| alias Test!(int) x;
|
`----

Andrew

The spec states 'type names'. 'int' is a type name - afaiks there is nothing that specifies the the parameter must be an instance of a type for alias to work as you have said. Class and template type name specifiers work just fine with alias parameters - only primitive type typenames fail.

Andrew Edwards wrote:

> 
> That's not a bug, just improper usage.
> should be:
> ,----[  ]
> |
> | template Test(alias T) {}
> | int x; // variable can be of any type (structs and classes included)
> | alias Test!(x) aint;
> |
> `----
> 
> or:
> 
> ,----[  ]
> |
> | template Test(T) {}
> | alias Test!(int) x;
> |
> `----
> 
> Andrew

> The spec states 'type names'. 'int' is a type name - afaiks there is
nothing
> that specifies the the parameter must be an instance of a type for alias
to
> work as you have said. Class and template type name specifiers work just fine with alias parameters - only primitive type typenames fail.

The spec. example that proves this interpretation correct:

class Foo
{
    static int p;
}

template Bar(alias T)
{
    alias T.p q;
}

void test()
{
    alias Bar!(Foo) bar;
    bar.q = 3; // sets Foo.p to 3
}

I thought I had misinterpreted that first paragraph in the alias section of the spec.

> Andrew Edwards wrote:
>
> >
> > That's not a bug, just improper usage.
> > should be:
> > ,----[  ]
> > |
> > | template Test(alias T) {}
> > | int x; // variable can be of any type (structs and classes included)
> > | alias Test!(x) aint;
> > |
> > `----
> >
> > or:
> >
> > ,----[  ]
> > |
> > | template Test(T) {}
> > | alias Test!(int) x;
> > |
> > `----
> >
> > Andrew
>

"Cabal" <cabalN05P4M@myrealbox.com> wrote in message news:cd83h9$31fl$1@digitaldaemon.com...
> The spec states 'type names'. 'int' is a type name - afaiks there is
nothing
> that specifies the the parameter must be an instance of a type for alias
to
> work as you have said. Class and template type name specifiers work just fine with alias parameters - only primitive type typenames fail.

Sorry for the confusion. 'bit' is not a type name, but a keyword. A type name would be a typedef'd name, an alias name for a type, a class name, a struct name, etc.