Constuctor IFTI, and it's JANK

auto Foo(Char)(Char[] text)
    if ( !is(Char T : T[]) ) // Basically just ensure that `Char` isn't a string or array.
{
    import std.stdio;
    Foo!(Char[]) foo;
    foo.payload = text;
    pragma(msg, "function Char.stringof == "~Char.stringof);
    return foo;
}

struct Foo(StrT)
    if ( is(StrT CharT : CharT[]) ) // Ensure that `StrT` is a string|array; declare `CharT` as it's element type.
{
    StrT payload;
    pragma(msg, "struct StrT.stringof  == " ~ StrT.stringof);

    /// Bonus jank: These fail to compile because `CharT` isn't declared /in this scope/.
    // CharT ch;
    // pragma(msg, "struct CharT.stringof == " ~ CharT.stringof);
}

void main()
{
    import std.stdio;
    auto foo = Foo("x"); // IFTI for Foo constructor!
    writefln(foo.payload);
}