…-rs#103)

Example:

thread 'main' panicked at 'internal error: entered unreachable code: while processing package trio: accum_term = 0.19 isn't a subset of incompat_term = 0.19.0, which means the last assignment should have been a decision, but instead it was a derivation. This shouldn't be possible! (Maybe your Version ordering is broken?)', /home/njs/src/pubgrub/src/internal/partial_solution.rs:411:17
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Fixes: pubgrub-rsgh-102

* feat: add logging to help debugging

* debug: impl Display for partial solution

* fix cherry picking

* Fix display of assignments in partial_solution

* debug: nits

Co-authored-by: Jacob Finkelman <Eh2406@wayne.edu>

* refactor: introduce a trait for sets of versions

* refactor: port report and incompatibility to version set

* refactor: port errors to version set

* refactor: port partial solution to version set

* refactor: move DependencyConstraints to type_aliases

* refactor: port core to version set

* refactor: port solver to version set

* refactor: replace old modules with ones based on version_set

* refactor: update tests to version_set

* feat: add serde bounds to OfflineDependencyProvider

* refactor: update proptest.rs to VersionSet

* docs: fix links

* refactor: allow clippy type_complexity

* Small docs changes

* refactor: replace Range with a bounded implementation

* fix: rewrite range proptest strategy

* fix: deserialize SmallVec without Vec alloc

* fix: remove not_equals

* fix: re-add union and remove early out

* fix: renamed V to VS in bench

* refactor: simpler intersection

Co-authored-by: Jacob Finkelman <Eh2406@wayne.edu>

* test: use deltas for range strategy

Co-authored-by: Jacob Finkelman <Eh2406@wayne.edu>

* docs(range): added comment about discrete values

* More restrictive for valid random range generation

* Remove duplicate check in check_invariants

* Add warning about non-unique ranges representations

* Rename start_bounded into start_unbounded

Co-authored-by: Jacob Finkelman <Eh2406@wayne.edu>
Co-authored-by: Matthieu Pizenberg <matthieu.pizenberg@gmail.com>

- Reduces nesting, to increase legibility of code
- Turns expect into error
- Removes unwrap()

…b-rs#146)

BREAKING CHANGE: Changes the API of DependencyProvider

…s#147)