message: Use BoundExpression instead of BoundColumnRefExpression.
diff: #include "optimizer/ca_optimizer.hpp"
  -#include "parser/expression/bound_columnref_expression.hpp"
  +#include "parser/expression/bound_expression.hpp"
  #include "planner/operator/logical_filter.hpp"
  #include "planner/operator/logical_projection.hpp"
  @@ -59,9 +59,9 @@ void CommonAggregateOptimizer::ExtractCommonAggregateExpressions(LogicalOperator
  unique_ptr<Expression> bce = projection.expressions[*it]->Copy();
  - // TODO: do we need to assert that bce is a BoundColumnRefExpression?
  + // TODO: do we need to assert that bce is a BoundExpression?
  - static_cast<BoundColumnRefExpression&>(*bce).binding.column_index = projection_index;
  + static_cast<BoundExpression&>(*bce).index = projection_index;
  while (it != positions.end()) {
  new_projection_expressions[*it] = bce->Copy();
  