Exception from command history after a "using namespace" statement on Pwsh cmd line

[ZStoner]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues, especially the pinned issues.

Exception report

### Environment
PSReadLine: 2.3.5+2cc85806c561a9395751a96a818e8ff1592d19f7
PowerShell: 7.4.2
OS: Microsoft Windows 10.0.22631
BufferWidth: 160
BufferHeight: 9000

Last 30 Keys:

 Enter
 Enter
 Ctrl+v Enter
 Ctrl+v Spacebar | Shift+Spacebar o u t - n Tab Enter
 " " + Spacebar Ctrl+v Enter
 Ctrl+v Enter
 Enter
 Ctrl+v Enter
 Ctrl+v Enter
 [ R

### Exception

System.Management.Automation.PSArgumentException: Cannot process argument because the value of argument "name" is not valid. Change the value of the "name" argument and run the operation again.
   at System.Management.Automation.Language.TypeName..ctor(IScriptExtent extent, String name)
   at System.Management.Automation.Language.TypeResolver.ResolveTypeNameWithContext(TypeName typeName, Exception& exception, Assembly[] assemblies, TypeResolutionState typeResolutionState)
   at System.Management.Automation.Language.SymbolResolver.VisitTypeName(TypeName typeName, Int32 genericArgumentCount, Boolean isAttribute)
   at System.Management.Automation.Language.SymbolResolver.VisitTypeExpression(TypeExpressionAst typeExpressionAst)
   at System.Management.Automation.Language.CommandExpressionAst.InternalVisit(AstVisitor visitor)
   at System.Management.Automation.Language.NamedBlockAst.InternalVisit(AstVisitor visitor)
   at System.Management.Automation.Language.ScriptBlockAst.InternalVisit(AstVisitor visitor)
   at System.Management.Automation.Language.SymbolResolver.ResolveSymbols(Parser parser, ScriptBlockAst scriptBlockAst)
   at System.Management.Automation.Language.ScriptBlockAst.PerformPostParseChecks(Parser parser)
   at System.Management.Automation.Language.Parser.ParseTask(String fileName, String input, List`1 tokenList, Boolean recursed, ParseMode parseMode)
   at System.Management.Automation.Language.Parser.Parse(String fileName, String input, List`1 tokenList, ParseError[]& errors, ParseMode parseMode)
   at System.Management.Automation.Language.Parser.ParseInput(String input, String fileName, Token[]& tokens, ParseError[]& errors)

Screenshot

Environment data

PS Version: 7.4.2
PS HostName: ConsoleHost
PSReadLine Version: 2.3.5
PSReadLine EditMode: Windows
OS: 10.0.22621.1 (WinBuild.160101.0800)
BufferWidth: 160
BufferHeight: 9000

Steps to reproduce

I ran into this when looking for a way to simplify the type name of a fully-qualified type, like [System.Security.Cryptography.RandomNumberGenerator] so that I could reference it simply as [RandomNumberGenerator]. Powershell has the using namespace or using assembly statements to assist with this.

1. PS> using namespace [System.Security.Cryptography]
2. PS> #[RandomNumberGenerator]::GetBytes(32)
   • [Note]: This command is commented to prevent syntax parsing, but this is what I eventually wanted to try.
   • The #commented version of this line is not required for the repro.
3. Attempt to type the following characters from above (don't directly paste the command)...
   • PS> [ R a n d o m . . .
4. PSReadLine will throw an exception as soon as you type the R in [Random.
   • I wasn't even able to attempt a Tab-completion or RightArrow statement completion.

Expected behavior

Expected no error, no thrown exception, and allow me to continue typing out the command line.

Actual behavior

• As soon as I typed the R when attempting to type [RandomNumberGenerator], it threw an error exception.
• The screenshot shows the last successfully typed char was the opening [.
  • The attempted R isn't shown as the exception was part of its keystroke.
• Repeating this in a new PWSH shell wil repro.

[Note]: For now, I have since deleted these commands from my ConsoleHost_History.txt to prevent me from accidentally triggering the error in the future. 😄

[MartinGC94]

This has been fixed in the 7.5.0 preview 2 release: https://github.com/PowerShell/PowerShell/releases/tag/v7.5.0-preview.2 I don't know if they have any plans to backport it to 7.4 though.

[daxian-dbw]

Right, it's a parsing bug in PowerShell engine, which was fixed by PowerShell/PowerShell#21162. I doubt if it meets the bar for backporting to 7.4.