provide manual clone implementations

Author: frankmcsherry

src/trace/wrappers/enter.rs

@@ -113,12 +113,20 @@ where
 
 
 /// Wrapper to provide batch to nested scope.
-#[derive(Clone)]
 pub struct BatchEnter<B, TInner> {
     batch: B,
     description: Description<TInner>,
 }
 
+impl<B: Clone, TInner: Clone> Clone for BatchEnter<B, TInner> {
+    fn clone(&self) -> Self {
+        BatchEnter {
+            batch: self.batch.clone(),
+            description: self.description.clone(),
+        }
+    }
+}
+
 impl<B, TInner> BatchReader for BatchEnter<B, TInner>
 where
     B: BatchReader,

src/trace/wrappers/enter_at.rs

@@ -131,13 +131,22 @@ where
 
 
 /// Wrapper to provide batch to nested scope.
-#[derive(Clone)]
 pub struct BatchEnter<B, TInner, F> {
     batch: B,
     description: Description<TInner>,
     logic: F,
 }
 
+impl<B: Clone, TInner: Clone, F: Clone> Clone for BatchEnter<B, TInner, F> {
+    fn clone(&self) -> Self {
+        BatchEnter {
+            batch: self.batch.clone(),
+            description: self.description.clone(),
+            logic: self.logic.clone(),
+        }
+    }
+}
+
 impl<B, TInner, F> BatchReader for BatchEnter<B, TInner, F>
 where
     B: BatchReader,

src/trace/wrappers/filter.rs

@@ -76,12 +76,20 @@ where
 
 
 /// Wrapper to provide batch to nested scope.
-#[derive(Clone)]
 pub struct BatchFilter<B, F> {
     batch: B,
     logic: F,
 }
 
+impl<B: Clone, F: Clone> Clone for BatchFilter<B, F> {
+    fn clone(&self) -> Self {
+        BatchFilter {
+            batch: self.batch.clone(),
+            logic: self.logic.clone(),
+        }
+    }
+}
+
 impl<B, F> BatchReader for BatchFilter<B, F>
 where
     B: BatchReader,

src/trace/wrappers/frontier.rs

@@ -83,13 +83,21 @@ where
 
 
 /// Wrapper to provide batch to nested scope.
-#[derive(Clone)]
 pub struct BatchFrontier<B: BatchReader> {
     batch: B,
     frontier: Antichain<B::Time>,
 }
 
-impl<B: BatchReader> BatchReader for BatchFrontier<B>
+impl<B: BatchReader+Clone> Clone for BatchFrontier<B> where B::Time: Clone {
+    fn clone(&self) -> Self {
+        BatchFrontier {
+            batch: self.batch.clone(),
+            frontier: self.frontier.to_owned(),
+        }
+    }
+}
+
+impl<B> BatchReader for BatchFrontier<B>
 where
     B: BatchReader,
     B::Time: Timestamp+Lattice,