struct Type(alias a, alias b) {
	alias b ThisWasB;
}

template MakeType(alias a, alias b)
{
alias Type!(a, b) MakeType;
}

template Foo(alias a, U)
{
	alias U.ThisWasB b;
	pragma(msg, b.stringof); // gives us the 7
//...
}

alias MakeType!(5, 7) MyType;
alias Foo!(5, MyType) Fooed;