refactor: Restrict with_log to the Storage types

Not strictly necessary, but it documents things better and may make some
mistakes impossible

Author: Markus Westerlind

src/snapshot_vec.rs

@@ -163,13 +163,14 @@ impl<D: SnapshotVecDelegate, V: VecLike<D> + Default, L: Default> SnapshotVec<D,
     }
 }
 
-impl<D: SnapshotVecDelegate, V: VecLike<D>, L> SnapshotVec<D, V, L> {
-    /// Creates a `SnapshotVec` using the `undo_log`, allowing mutating methods to be
-    /// called if `L` does not implement `UndoLogs`
-    pub fn with_log<'a, L2>(&'a mut self, undo_log: L2) -> SnapshotVec<D, &'a mut V, L2>
+impl<D: SnapshotVecDelegate> SnapshotVecStorage<D> {
+    /// Creates a `SnapshotVec` using the `undo_log`, allowing mutating methods to be called
+    pub fn with_log<'a, L>(
+        &'a mut self,
+        undo_log: L,
+    ) -> SnapshotVec<D, &'a mut Vec<<D as SnapshotVecDelegate>::Value>, L>
     where
-        L2: UndoLogs<UndoLog<D>>,
-        &'a mut V: VecLike<D>,
+        L: UndoLogs<UndoLog<D>>,
     {
         SnapshotVec {
             values: &mut self.values,

src/unify/mod.rs

@@ -243,20 +243,18 @@ impl<K: UnifyKey> VarValue<K> {
         }
     }
 }
-impl<K, V, L> UnificationTable<InPlace<K, V, L>>
+impl<K> UnificationTableStorage<K>
 where
     K: UnifyKey,
-    V: sv::VecLike<Delegate<K>>,
 {
     /// Creates a `UnificationTable` using an external `undo_log`, allowing mutating methods to be
     /// called if `L` does not implement `UndoLogs`
-    pub fn with_log<'a, L2>(
+    pub fn with_log<'a, L>(
         &'a mut self,
-        undo_log: L2,
-    ) -> UnificationTable<InPlace<K, &'a mut V, L2>>
+        undo_log: L,
+    ) -> UnificationTable<InPlace<K, &'a mut UnificationStorage<K>, L>>
     where
-        L2: UndoLogs<sv::UndoLog<Delegate<K>>>,
-        &'a mut V: sv::VecLike<Delegate<K>>,
+        L: UndoLogs<sv::UndoLog<Delegate<K>>>,
     {
         UnificationTable {
             values: InPlace {