Implicit bindings will cause very confusing crashes in the backend at
present, so this is intended at least partially as a stop gap until we
get them implemented (see #110722).
However, I do think that this is useful in the longer term as well as an
off-by-default warning, as it is quite easy to miss a binding or two
when using explicit bindings and the results of that can be surprisingly
hard to debug. I've filed #135907 to track turning this into an
off-by-default warning or removing it eventually as we see fit.
d35bf17e8a