Repository: PowerShell/PowerShell
File: src/Microsoft.PowerShell.Commands.Utility/commands/utility/Var.cs (C#)

Code before:
        private SessionStateEntryVisibility? _visibility;

        /// <summary>
        /// The variable object should be passed down the pipeline.
        /// </summary>
        [Parameter]
        public SwitchParameter PassThru
        {
            get
            {
                return _passThru;
            }

            set
            {
                _passThru = value;
            }
        }

        private bool _passThru;

        /// <summary>
        /// Gets whether we will append to the variable if it exists.
        /// </summary>
        [Parameter]
        [Experimental("PSRedirectToVariable", ExperimentAction.Show)]
        public SwitchParameter Append { get; set; }

        private bool _nameIsFormalParameter;
        private bool _valueIsFormalParameter;
        #endregion parameters

        /// <summary>
        /// Checks to see if the name and value parameters were bound as formal parameters.
        /// </summary>
        protected override void BeginProcessing()
        {
            if (Name != null && Name.Length > 0)
            {
                _nameIsFormalParameter = true;
            }

            if (Value != AutomationNull.Value)
            {
                _valueIsFormalParameter = true;
            }

            if (Append)
            {
                // create the list here and add to it if it has a value
                // but if they have more than one name, produce an error

Review comment (suggestion):
```suggestion
        [Experimental(ExperimentalFeature.PSRedirectToVariable, ExperimentAction.Show)]
```

You already have the const string defined in this class

Code after:
        private SessionStateEntryVisibility? _visibility;

        /// <summary>
        /// The variable object should be passed down the pipeline.
        /// </summary>
        [Parameter]
        public SwitchParameter PassThru
        {
            get
            {
                return _passThru;
            }

            set
            {
                _passThru = value;
            }
        }

        private bool _passThru;

        /// <summary>
        /// Gets whether we will append to the variable if it exists.
        /// </summary>
        [Parameter]
        [Experimental(ExperimentalFeature.PSRedirectToVariable, ExperimentAction.Show)]
        public SwitchParameter Append { get; set; }

        private bool _nameIsFormalParameter;
        private bool _valueIsFormalParameter;
        #endregion parameters

        /// <summary>
        /// Checks to see if the name and value parameters were bound as formal parameters.
        /// </summary>
        protected override void BeginProcessing()
        {
            if (Name != null && Name.Length > 0)
            {
                _nameIsFormalParameter = true;
            }

            if (Value != AutomationNull.Value)
            {
                _valueIsFormalParameter = true;
            }

            if (Append)
            {
                // create the list here and add to it if it has a value
                // but if they have more than one name, produce an error