code: private static boolean tryConvertAllBlockScopedFollowing(Node start) {
      if (NodeUtil.isWithinLoop(start)) {
        // If in a loop, don't convert anything to a var. Return true only if there are no let/consts.
        return !hasBlockScopedVarsFollowing(start);
      }
      for (Node n = start.getNext(); n != null; n = n.getNext()) {
        if (n.isLet() || n.isConst()) {
          n.setToken(Token.VAR);
        }
      }
      return true;
    }
docs: Convert all let/const declarations following the start node to var declarations if possible.
  
  <p>See the unit tests for examples of why this is necessary before moving code into an inner
  block, and why this is unsafe to do to declarations inside a loop.
  
  @param start The start point
  @return Whether all block-scoped declarations have been converted.