I’d have to think about this more carefully, but my off-the-cuff reaction is that this loses a key invariant that made name resolution tractable, which is that we always know the “full path” that is being imported.
In particular, the challenge is when you have a module like this:
use foo::bar;
...
baz!(...);
and you know that the foo crate is available, you still have to wait until you expand baz! to know whether it is going to generate a mod foo that would have shadowed foo.
Now, sometimes we handle this with a kind of “time travel violation” rule, where we go ahead and resolve to the crate but come back with an error if a module arises later that shadows – but you said that the module would take precedence, so that is harder.
That said, i’m a bit out of date on how things work, @petrochenkov may be able to weigh in on the latest tricks.
(I’d love to create a formal model of the name resolution system, as an aside, analogous to Chalk…)