presto-main/src/main/java/io/prestosql/sql/planner/ExpressionNodeInliner.java/ExpressionNodeInliner/rewriteExpression
class ExpressionNodeInliner:    @Override
    public Expression rewriteExpression(Expression node, Void context, ExpressionTreeRewriter<Void> treeRewriter)
    {
        return mappings.get(node);
    }