Allow Ranges::contains to accept (e.g.) &str for Ranges<String> (#35)

## Summary

This PR borrows a trick from
[HashMap](https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.contains_key)
to enable users to pass (e.g.) `&str` to `Ranges::contains`, given
`Ranges<String>`.

Author: charliermarsh

src/internal/arena.rs

@@ -150,9 +150,7 @@ impl<T: Hash + Eq + fmt::Debug> fmt::Debug for HashArena<T> {
 
 impl<T: Hash + Eq> HashArena<T> {
     pub fn new() -> Self {
-        HashArena {
-            data: FnvIndexSet::default(),
-        }
+        Self::default()
     }
 
     pub fn alloc(&mut self, value: T) -> Id<T> {
@@ -161,6 +159,14 @@ impl<T: Hash + Eq> HashArena<T> {
     }
 }
 
+impl<T: Hash + Eq> Default for HashArena<T> {
+    fn default() -> Self {
+        Self {
+            data: FnvIndexSet::default(),
+        }
+    }
+}
+
 impl<T: Hash + Eq> Index<Id<T>> for HashArena<T> {
     type Output = T;
     fn index(&self, id: Id<T>) -> &T {

src/internal/core.rs

@@ -83,7 +83,7 @@ impl<DP: DependencyProvider> State<DP> {
         let dep_incompats =
             self.add_incompatibility_from_dependencies(package, version.clone(), dependencies);
         self.partial_solution.add_package_version_incompatibilities(
-            package.clone(),
+            package,
             version.clone(),
             dep_incompats,
             &self.incompatibility_store,

src/solver.rs

@@ -171,7 +171,7 @@ pub fn resolve<DP: DependencyProvider>(
             };
 
             // Add that package and version if the dependencies are not problematic.
-            state.add_package_version_dependencies(p.clone(), v.clone(), dependencies);
+            state.add_package_version_dependencies(p, v.clone(), dependencies);
         } else {
             // `dep_incompats` are already in `incompatibilities` so we know there are not satisfied
             // terms and can add the decision directly.

version-ranges/src/lib.rs

@@ -229,7 +229,11 @@ impl<V: Ord> Ranges<V> {
     }
 
     /// Returns true if self contains the specified value.
-    pub fn contains(&self, version: &V) -> bool {
+    pub fn contains<Q>(&self, version: &Q) -> bool
+    where
+        V: Borrow<Q>,
+        Q: ?Sized + PartialOrd,
+    {
         self.segments
             .binary_search_by(|segment| {
                 // We have to reverse because we need the segment wrt to the version, while
@@ -470,19 +474,23 @@ impl<V: Ord> Ord for Ranges<V> {
 ///   ^      ^      ^
 ///   less   equal  greater
 /// ```
-fn within_bounds<V: PartialOrd>(version: &V, segment: &Interval<V>) -> Ordering {
+fn within_bounds<Q, V>(version: &Q, segment: &Interval<V>) -> Ordering
+where
+    V: Borrow<Q>,
+    Q: ?Sized + PartialOrd,
+{
     let below_lower_bound = match segment {
-        (Excluded(start), _) => version <= start,
-        (Included(start), _) => version < start,
+        (Excluded(start), _) => version <= start.borrow(),
+        (Included(start), _) => version < start.borrow(),
         (Unbounded, _) => false,
     };
     if below_lower_bound {
         return Ordering::Less;
     }
     let below_upper_bound = match segment {
         (_, Unbounded) => true,
-        (_, Included(end)) => version <= end,
-        (_, Excluded(end)) => version < end,
+        (_, Included(end)) => version <= end.borrow(),
+        (_, Excluded(end)) => version < end.borrow(),
     };
     if below_upper_bound {
         return Ordering::Equal;
@@ -1304,7 +1312,7 @@ pub mod tests {
 
         #[test]
         fn always_contains_exact(version in version_strat()) {
-            assert!(Ranges::singleton(version).contains(&version));
+            assert!(Ranges::<u32>::singleton(version).contains(&version));
         }
 
         #[test]
@@ -1326,7 +1334,7 @@ pub mod tests {
 
         #[test]
         fn from_range_bounds(range in any::<(Bound<u32>, Bound<u32>)>(), version in version_strat()) {
-            let rv: Ranges<_> = Ranges::from_range_bounds(range);
+            let rv: Ranges<_> = Ranges::<u32>::from_range_bounds(range);
             assert_eq!(range.contains(&version), rv.contains(&version));
         }