dotnet/roslyn

NullReferenceException when calling SyntaxFactory.ParseArgumentList

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#58,668 opened on Jan 6, 2022

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Area-CompilersBugLanguage-VBhelp wanted

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Description

Version Used: Nuget Microsoft.CodeAnalysis.VisualBasic Versions=4.0.1, 3.11.0

What are we trying to do? Parse an argument list (and recieving an unexpected exception (presumably because the input is invalid).)

  1. Reference Microsoft.CodeAnalysis.VisualBasic package in a project
  2. Call SyntaxFactory.ParseArgumentList("42")

Expected Behavior: Correct parsing of the argument. At least a more understandable exception like ArgumentException or similar, but not a direct bubbling of an internal exception.

Actual Behavior: NullReferenceExceptionwhen calling a static method.

The current implementation is quite misleading. As soon as one changes the passed string to contain parenthesis (turn "42" into "(42)") the parsing works. Which could be acceptable behavior. But simply passing on the internal exception is not. It should be something else.

Contributor guide

Research direction
Investigate the internal implementation of SyntaxFactory.ParseArgumentList to locate where a null reference occurs and add proper argument validation.
Tech stack
csharp
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#Roslyn
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70