template isSomeFunction(T...)

if (T.length == 1)

{

    static if (is(typeof(& T[0]) U : U*) && is(U == function) || is(typeof(& T[0]) U == delegate))

    {

        // T is a (nested) function symbol.

        enum bool isSomeFunction = true;

    }

    else static if (is(T[0] W) || is(typeof(T[0]) W))

    {

        // T is an expression or a type.  Take the type of it and examine.

        static if (is(W F : F*) && is(F == function))

            enum bool isSomeFunction = true; // function pointer

        else

            enum bool isSomeFunction = is(W == function) || is(W == delegate);

    }

    else

        enum bool isSomeFunction = false;

}

​

struct MySerializer (T)

{

    void serializeSinkType(T2) (scope auto ref T2 record) {}

}

​

template SupportSinkTypeSer(SerT)

{

    enum SupportSinkTypeSer = isSomeFunction!(SerT.init.serializeSinkType!int);

}

​

int main()

{

    enum x = SupportSinkTypeSer!(MySerializer!int);

    return 0;

}