void visitLocalVariable(String name, String desc, String signature, Label start, Label end, int index) {
                hasLocalVars = true
            }

            @Override
            void visitLineNumber(int line, Label start) {
                hasLineNumbers = true
            }
        }
        def visitor = new ClassVisitor(AsmConstants.ASM_LEVEL) {
            @Override

            MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
                new MethodVisitor(Opcodes.ASM7) {
                    @Override
                    void visitLineNumber(int line, Label start) {
                        throw new AssertionError("Should not produce any line number information but " +
                            "method $name$desc contains line $line label $start")