AD0001 Analyzer 'FakeItEasy.Analyzer.UnusedReturnValueAnalyzer' threw an exception

I was trying out https://www.nuget.org/packages/FakeItEasy.Analyzer/ and got a bunch of warnings, all in the same style. The SyntaxNode exists, but isn’t called in any way by FakeItEasy (A.…) code.

Don’t know if you guys can make something of this, if not then close as I wont be spending time analyzing this further.

Severity    Code    Description Project File    Line    Source  Suppression State   Detail Description
Warning AD0001  Analyzer 'FakeItEasy.Analyzer.UnusedReturnValueAnalyzer' threw an exception of type 'System.ArgumentNullException' with message 'Value cannot be null.
Parameter name: syntax'.    <Project>       1   IntelliSense    Active  Analyzer 'FakeItEasy.Analyzer.UnusedReturnValueAnalyzer' threw the following exception:
'Exception occurred with following context:
Compilation: <Project>
SyntaxTree: C:\Source\<Project>\AnalyzerTests.cs
SyntaxNode: CreateId() [InvocationExpressionSyntax]@[4016..4026) (118,46)-(118,56)

System.ArgumentNullException: Value cannot be null.
Parameter name: syntax
   at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.CheckSyntaxNode(CSharpSyntaxNode syntax)
   at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.GetSymbolInfo(ExpressionSyntax expression, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.CSharp.CSharpExtensions.GetSymbolInfo(SemanticModel semanticModel, ExpressionSyntax expression, CancellationToken cancellationToken)
   at FakeItEasy.Analyzer.UnusedReturnValueAnalyzer.GetCalledMethodSymbol(InvocationExpressionSyntax call, SyntaxNodeAnalysisContext context)
   at FakeItEasy.Analyzer.UnusedReturnValueAnalyzer.AnalyzeCall(SyntaxNodeAnalysisContext context)
   at Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.<>c__DisplayClass42_1`1.<ExecuteSyntaxNodeAction>b__1()
   at Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteAndCatchIfThrows_NoLock(DiagnosticAnalyzer analyzer, Action analyze, Nullable`1 info)
-----
'.

[adamralph]

@Mertsch OK, thanks. I’ve managed to reproduce it now. The use of JetBrains.Annotations appears to be irrelevant:

1. Create a class library
2. Install-Package FakeItEasy.Analyzer
3. Add this code:

    public class Foo
    {
        public void Bar()
        {
            Baz();
        }

        public void Baz()
        {
        }
    }

[blairconrad]

This issue has been fixed in release 2.1.0.

Thanks for your help, @Mertsch. Look for your name in the release notes! 🏆