Right, though I'm not sure it's easy to infer an ordinary function's return type from this kind of declaration. Speaking of return types, do you have any idea

Right, though I'm not sure it's easy to infer an ordinary function's return type from this kind of declaration. Speaking of return types, do you have any idea if any implementation takes a generic function's return type declaration seriously? I believe SBCL currently doesn't, which is unfortunate (defmethods keep clobbering the ftype declaration).