- encapsulate semantic more into helpers
- allow lazy scopes iteration
- simplify reporting code in tower resolver
- fix some inconsistencies and wrong lookups
- remove redundant lookup recordings
- remove lookup scopes for non-star imports
The commit is a refactoring and doesn't change the behaviour of
neither IC nor CRI. Changes in the lookups are mostly due to the
previous obviously wrong lookups (see changed test data).
Ilya Chernikov
a823bfd600