C++: Correct syntax for friending a template type member of template parameter?

I have a class that takes a template type parameter (tTRAIT). I want to friend a template type member alias of tTRAIT, but I can't figure out the syntax. (Is this even possible?).

template <bool bBOOL>
struct SFoo {};

struct STrait
    {
        template <bool bBOOL>
        using TFoo = SFoo<bBOOL>;
    };

template <typename tTRAIT>
struct SBar
    {
        template <bool bBOOL>
        friend typename tTRAIT::template TFoo<bBOOL>;
    };

SBar<STrait> bar;

Clang's error (on the friend line) is:

error: friend type templates must use an elaborated type

I have tried exhausting all possible combinations I can think of:

friend tTRAIT::TFoo;
friend tTRAIT::template TFoo;
friend typename tTRAIT::TFoo;
friend typename tTRAIT::template TFoo;
template <bool bBOOL> friend tTRAIT::TFoo;
template <bool bBOOL> friend tTRAIT::TFoo<bBOOL>;
template <bool bBOOL> friend tTRAIT::template TFoo;
template <bool bBOOL> friend tTRAIT::template TFoo<bBOOL>;
template <bool bBOOL> friend typename tTRAIT::TFoo;
template <bool bBOOL> friend typename tTRAIT::TFoo<bBOOL>;
template <bool bBOOL> friend typename tTRAIT::template TFoo;
template <bool bBOOL> friend typename tTRAIT::template TFoo<bBOOL>;

I have also tried using using, but it doesn't seem to help.

As an ugly hack (which only works for bool parameters), I can get it to work by friending each specialization manually.

friend typename tTRAIT::template TFoo<false>;
friend typename tTRAIT::template TFoo<true >;

But that's yucky.

Does anyone know how to do this, or if this can be done?