Use debug printlns, without the trait bounds (using specialization to find the right impl anyway).
NOTE: This uses experimental Rust features and is therefore
by itself experimental and unstable, and has all the problems of
For this reason,
unsafe is required to use this feature unfortunately.
Print a message, and then each value’s debug representation (if it has one)
This type always implements
Debug. Uses specialization to use
the inner value’s Debug (which it should basically always have).