dotnet/roslyn

Red squiggly line in VS when diagnostic is suppressed

Open

#57,041 opened on Oct 8, 2021

View on GitHubContributor guide
 (4 comments) (2 reactions) (0 assignees)C# (4,257 forks)batch import
Area-AnalyzersBughelp wanted

Repository metrics

Stars
 (20,414 stars)
PR merge metrics
 (Avg merge 6d 17h) (256 merged PRs in 30d)

Description

Version Used:

Microsoft Visual Studio Enterprise 2019 Version 16.11.3 Microsoft.CodeAnalysis Version 3.11.0

Steps to Reproduce:

This solution reproduces the issue: https://github.com/dotnet/roslyn/files/7303368/DUTester.zip It's using TreatWarningsAsErrors, meaning the reported CS8509 would fail the build.

  1. At line 14 in Program.cs there is a switch expression which reports a CS8509 warning. The warning is suppressed by another analyzer because it's a discriminated union, where the other analyzer checked that all cases are handled.

Expected Behavior: No squiggly lines on the switch expression

Actual Behavior: Squiggly lines on the switch expression. The build still succeeds, so it appears to be a visualization issue in VS.

Contributor guide

Research direction
Investigate the suppression mechanism in Roslyn analyzers and trace why the squiggly line persists despite the diagnostic being suppressed. Focus on the interaction between TreatWarningsAsErrors and custom analyzers.
Tech stack
csharp
Domain
developer experience
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.
Mostly clear
Prerequisites
C#Visual Studio
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60