* Returns false when the given statement may be ignored, provided all other statements in the script body may also be ignored.
     */
    public static boolean mayHaveAnEffect(Statement statement) {
        if (statement instanceof ReturnStatement) {
            ReturnStatement returnStatement = (ReturnStatement) statement;

            List<Statement> statements = source.getAST().getStatementBlock().getStatements();
            for (Statement statement : statements) {
                if (AstUtils.mayHaveAnEffect(statement)) {
                    return false;
                }
            }

            // No statements, or no statements that have an effect
            return true;
        }