message: refactor(mergeScan): Ensure buffered values are released.
diff: @@ -94,6 +94,7 @@ export function mergeScan<T, R>(
  // Intentially terse. Set the state, then emit it.
  subscriber.next((state = innerValue));
  },
  + // Errors are passed to the destination.
  undefined,
  () => {
  // The inner completed, decrement the number of actives.
  @@ -111,11 +112,24 @@ export function mergeScan<T, R>(
  };
  source.subscribe(
  - new OperatorSubscriber(subscriber, nextSourceValue, undefined, () => {
  + new OperatorSubscriber(
  + subscriber,
  + nextSourceValue,
  + // Errors are passed through
  + undefined,
  + () => {
  // Outer completed, make a note of it, and check to see if we can complete everything.
  isComplete = true;
  checkComplete();
  - })
  + }
  + )
  );
  +
  + // Additional teardown (for when the destination is torn down).
  + // Other teardown is added implicitly via subscription above.
  + return () => {
  + // Ensure buffered values are released.
  + buffer = null!;
  + };
  });
  }
  