Consider:

~ % dmd -v|head -n 1
DMD64 D Compiler v2.066-devel

~% cat mixin_template_pb.d
mixin template Foo(T) {
  void bar() {}
}

struct FooBar {
  mixin Foo!int;
  void bar(ulong d)() {}
}

void check() {
  FooBar o;
  o.bar();
}
~% dmd -c mixin_template_pb.d
mixin_template_pb.d(12): Error: template mixin_template_pb.FooBar.bar cannot deduce function from argument types !()(), candidates are:
mixin_template_pb.d(7):        mixin_template_pb.FooBar.bar(ulong d)()

It looks like the compiler does not see the mixed-in "bar". If I comment out the definition of "bar" in "FooBar", it compiles fine. Is this to be considered a bug?

On Tuesday, 20 January 2015 at 11:30:39 UTC, Luc Bourhis wrote:
> Consider:
>
> ~ % dmd -v|head -n 1
> DMD64 D Compiler v2.066-devel
>
> ~% cat mixin_template_pb.d
> mixin template Foo(T) {
>   void bar() {}
> }
>
> struct FooBar {
>   mixin Foo!int;
>   void bar(ulong d)() {}
> }
>
> void check() {
>   FooBar o;
>   o.bar();
> }
> ~% dmd -c mixin_template_pb.d
> mixin_template_pb.d(12): Error: template mixin_template_pb.FooBar.bar cannot deduce function from argument types !()(), candidates are:
> mixin_template_pb.d(7):        mixin_template_pb.FooBar.bar(ulong d)()
>
> It looks like the compiler does not see the mixed-in "bar". If I comment out the definition of "bar" in "FooBar", it compiles fine. Is this to be considered a bug?

No, it's working as intended: "If the name of a declaration in a mixin is the same as a declaration in the surrounding scope, the surrounding declaration overrides the mixin one" -- http://dlang.org/template-mixin.html

You can use `alias` to bring the two together:

struct FooBar {
  mixin Foo!int f;
  alias bar = f.bar;
  void bar(ulong d)() {}
}