CSC Error AD0001 CSharpDiagnosticAnalyzerApiUsageAnalyzer NullReferenceException

[MattOG]

Started getting this error after updating my solution to target .NetCore 3.0.

Attempted to use the (downgraded) version of 2.9.6-beta1.19502.2 as suggested here: #2889 (just in case) but as expected the error didn't go away.

It happens in 4 of the projects in the solution, each with a different entry under the ISymbol tag below.

Analyzer package

Microsoft.CodeAnalysis.FxCopAnalyzers

Package Version

v2.9.6 (Latest)

Diagnostic ID

AD0001 Analyzer 'Microsoft.CodeAnalysis.CSharp.Analyzers.MetaAnalyzers.CSharpDiagnosticAnalyzerApiUsageAnalyzer' threw an exception of type 'System.NullReferenceException' with message 'Object reference not set to an instance of an object.'.

Analyzer 'Microsoft.CodeAnalysis.CSharp.Analyzers.MetaAnalyzers.CSharpDiagnosticAnalyzerApiUsageAnalyzer' threw the following exception:
'Exception occurred with following context:
Compilation: ProNET.Web
ISymbol: Startup (NamedType)

System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.CodeAnalysis.Analyzers.MetaAnalyzers.DiagnosticAnalyzerApiUsageAnalyzer`1.AddUsedNamedTypeCore(ITypeSymbol typeOpt, Builder builder, Boolean& hasAccessToTypeFromWorkspaceAssemblies)
   at Microsoft.CodeAnalysis.Analyzers.MetaAnalyzers.DiagnosticAnalyzerApiUsageAnalyzer`1.AddUsedNamedTypeCore(ITypeSymbol typeOpt, Builder builder, Boolean& hasAccessToTypeFromWorkspaceAssemblies)
   at Microsoft.CodeAnalysis.Analyzers.MetaAnalyzers.DiagnosticAnalyzerApiUsageAnalyzer`1.GetUsedNamedTypes(INamedTypeSymbol namedType, Compilation compilation, CancellationToken cancellationToken, Boolean& hasAccessToTypeFromWorkspaceAssemblies)
   at Microsoft.CodeAnalysis.Analyzers.MetaAnalyzers.DiagnosticAnalyzerApiUsageAnalyzer`1.<>c__DisplayClass11_0.<Initialize>b__1(SymbolAnalysisContext symbolContext)
   at Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.<>c.<ExecuteSymbolActionsCore>b__43_1(ValueTuple`2 data)
   at Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteAndCatchIfThrows_NoLock[TArg](DiagnosticAnalyzer analyzer, Action`1 analyze, TArg argument, Nullable`1 info)
-----
'.

Repro steps

1. Updated project files.
2. Install NuGet packages.
3. Run analysis.

Expected behavior

Not an AD0001 error

Actual behavior

An AD001 error

[pleonex]

It's happening for us in .NET Framework 4.7.2 projects too.

[mavasani]

Can you try to add a package reference to the latest stable version of https://www.nuget.org/packages/Microsoft.CodeAnalysis.Analyzers/?

[MattOG]

@mavasani I have the latest version installed as detailed in the opening post. Unless 2.9.6 (which your link points to) isn't the latest?

[mavasani]

@MattOG Your description mentions you have installed 2.9.6 version of Microsoft.CodeAnalysis.FxCopAnalyzers, but that package does not contain the ApiUsageAnalyzer. Did you also install latest version of Microsoft.CodeAnalysis.Analyzers, which contains this analyzer?

[MattOG]

@mavasani Apologies, my ability to read seems to have gone astray.

I'm applying your suggestion now.

Thanks.

[MattOG]

@mavasani This has solved this issue.
Thanks for the help.