Ralf Hinze writes:

I like Andres' proposal. It puts some burden on the compiler writers (but this work has to be invested only once) and considerably simplifies things for the library writers.

Putting the burden on the compiler writers is exactly what we want to avoid - us compiler writers tend to be too busy writing compilers! Instead, what I would like to see is a separate library infrastructure built by non-compiler writers that smooths over the differences between