Fix persistent tables

Author: Markus Westerlind

src/unify/backing_vec.rs

@@ -178,9 +178,17 @@ impl<K: UnifyKey> Default for Persistent<K> {
 }
 
 #[cfg(feature = "persistent")]
-impl<K: UnifyKey> UnificationStore for Persistent<K> {
+impl<K: UnifyKey> UnificationStoreBase for Persistent<K> {
     type Key = K;
     type Value = K::Value;
+
+    fn len(&self) -> usize {
+        self.values.len()
+    }
+}
+
+#[cfg(feature = "persistent")]
+impl<K: UnifyKey> UnificationStore for Persistent<K> {
     type Snapshot = Self;
 
     #[inline]
@@ -211,10 +219,6 @@ impl<K: UnifyKey> UnificationStore for Persistent<K> {
         }
     }
 
-    fn len(&self) -> usize {
-        self.values.len()
-    }
-
     #[inline]
     fn push(&mut self, value: VarValue<Self::Key>) {
         self.values.push(value);

src/unify/tests.rs

@@ -93,7 +93,9 @@ fn big_array() {
 }
 
 #[cfg(feature = "bench")]
-fn big_array_bench_generic<S: UnificationStore<Key = UnitKey, Value = ()>>(b: &mut Bencher) {
+fn big_array_bench_generic<S: Default + UnificationStore<Key = UnitKey, Value = ()>>(
+    b: &mut Bencher,
+) {
     let mut ut: UnificationTable<S> = UnificationTable::new();
     let mut keys = Vec::new();
     const MAX: usize = 1 << 15;
@@ -128,7 +130,7 @@ fn big_array_bench_Persistent(b: &mut Bencher) {
 }
 
 #[cfg(feature = "bench")]
-fn big_array_bench_in_snapshot_generic<S: UnificationStore<Key = UnitKey, Value = ()>>(
+fn big_array_bench_in_snapshot_generic<S: Default + UnificationStore<Key = UnitKey, Value = ()>>(
     b: &mut Bencher,
 ) {
     let mut ut: UnificationTable<S> = UnificationTable::new();
@@ -169,7 +171,11 @@ fn big_array_bench_in_snapshot_Persistent(b: &mut Bencher) {
 }
 
 #[cfg(feature = "bench")]
-fn big_array_bench_clone_generic<S: UnificationStore<Key = UnitKey, Value = ()>>(b: &mut Bencher) {
+fn big_array_bench_clone_generic<
+    S: Default + Clone + UnificationStore<Key = UnitKey, Value = ()>,
+>(
+    b: &mut Bencher,
+) {
     let mut ut: UnificationTable<S> = UnificationTable::new();
     let mut keys = Vec::new();
     const MAX: usize = 1 << 15;