Repository: PowerShell/PowerShell
File: src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs (C#)

Code before:
        /// </summary>
        /// <value></value>
        /// <exception/>
        public override PSHostUserInterface UI
        {
            get
            {
                Dbg.Assert(ui != null, "ui should have been allocated in ctor");
                return ui;
            }
        }

        /// <summary>
        /// See base class.
        /// </summary>
        public void PushRunspace(Runspace newRunspace)
        {
            if (_runspaceRef == null)
            {
                return;
            }

            RemoteRunspace remoteRunspace = newRunspace as RemoteRunspace;
            Dbg.Assert(remoteRunspace != null, "Expected remoteRunspace != null");
            remoteRunspace.StateChanged += HandleRemoteRunspaceStateChanged;

            // Unsubscribe the local session debugger.
            if (_runspaceRef.Runspace.Debugger != null)
            {
                _runspaceRef.Runspace.Debugger.DebuggerStop -= OnExecutionSuspended;
            }

            // Subscribe to debugger stop event.
            if (remoteRunspace.Debugger != null)
            {
                remoteRunspace.Debugger.DebuggerStop += OnExecutionSuspended;
            }

            // Connect a disconnected command.
            this.runningCmd = EnterPSSessionCommand.ConnectRunningPipeline(remoteRunspace);

            // Push runspace.
            _runspaceRef.Override(remoteRunspace, hostGlobalLock, out _isRunspacePushed);
            RunspacePushed.SafeInvoke(this, EventArgs.Empty);

            if (this.runningCmd != null)
            {
                EnterPSSessionCommand.ContinueCommand(
                    remoteRunspace,
                    this.runningCmd,
                    this,

Review comment (suggestion):
Please use modern syntax:
```suggestion
            RemoteRunspace remoteRunspace = runspace as RemoteRunspace;
            if (remoteRunspace is not RemoteRunspace remoteRunspace)
            {
                throw new ArgumentException(ConsoleHostStrings.PushRunspaceNotRemote, nameof(runspace));
            }
```

Code after:
        /// </summary>
        /// <value></value>
        /// <exception/>
        public override PSHostUserInterface UI
        {
            get
            {
                Dbg.Assert(ui != null, "ui should have been allocated in ctor");
                return ui;
            }
        }

        /// <summary>
        /// See base class.
        /// </summary>
        public void PushRunspace(Runspace runspace)
        {
            if (_runspaceRef == null)
            {
                return;
            }

            if (runspace is not RemoteRunspace remoteRunspace)
            {
                throw new ArgumentException(ConsoleHostStrings.PushRunspaceNotRemote, nameof(runspace));
            }

            remoteRunspace.StateChanged += HandleRemoteRunspaceStateChanged;

            // Unsubscribe the local session debugger.
            if (_runspaceRef.Runspace.Debugger != null)
            {
                _runspaceRef.Runspace.Debugger.DebuggerStop -= OnExecutionSuspended;
            }

            // Subscribe to debugger stop event.
            if (remoteRunspace.Debugger != null)
            {
                remoteRunspace.Debugger.DebuggerStop += OnExecutionSuspended;
            }

            // Connect a disconnected command.
            this.runningCmd = EnterPSSessionCommand.ConnectRunningPipeline(remoteRunspace);

            // Push runspace.
            _runspaceRef.Override(remoteRunspace, hostGlobalLock, out _isRunspacePushed);
            RunspacePushed.SafeInvoke(this, EventArgs.Empty);

            if (this.runningCmd != null)
            {
                EnterPSSessionCommand.ContinueCommand(