Fix analyzer RCS1090 - Check ConfigureAwait argument value (#1566)

Author: josefpihrt

ChangeLog.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix analyzer [RCS1090](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1090) ([PR](https://github.com/dotnet/roslynator/pull/1566))
+
 ### Change
 
 - Update analyzer [RCS1077](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1077) ([PR](https://github.com/dotnet/roslynator/pull/1653))

src/Analyzers/CSharp/Analysis/ConfigureAwaitAnalyzer.cs

@@ -2,6 +2,7 @@
 
 using System.Collections.Immutable;
 using System.Linq;
+using System.Threading;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
@@ -87,7 +88,7 @@ private static void RemoveCallToConfigureAwait(SyntaxNodeAnalysisContext context
         //             ^^^^^^^^^^^^^^^^^^^^^^
         SimpleMemberInvocationExpressionInfo invocationInfo = SyntaxInfo.SimpleMemberInvocationExpressionInfo(expression);
 
-        if (!IsConfigureAwait(invocationInfo))
+        if (!IsConfigureAwaitFalse(invocationInfo, context.SemanticModel, context.CancellationToken))
             return;
 
         ITypeSymbol awaitedType = context.SemanticModel.GetTypeSymbol(expression, context.CancellationToken);
@@ -133,6 +134,13 @@ private static bool IsConfigureAwait(SimpleMemberInvocationExpressionInfo invoca
             && invocationInfo.Arguments.Count == 1;
     }
 
+    private static bool IsConfigureAwaitFalse(SimpleMemberInvocationExpressionInfo invocationInfo, SemanticModel semanticModel, CancellationToken cancellationToken)
+    {
+        return IsConfigureAwait(invocationInfo)
+            && semanticModel.GetConstantValue(invocationInfo.Arguments[0].Expression, cancellationToken).Value is bool boolValue
+            && !boolValue;
+    }
+
     private static bool IsConfigureAwaitable(ITypeSymbol typeSymbol, SemanticModel semanticModel, int position)
     {
         return semanticModel.LookupSymbols(position, typeSymbol, "ConfigureAwait", includeReducedExtensionMethods: true)

src/Tests/Analyzers.Tests/RCS1090RemoveCallToConfigureAwaitTests.cs

@@ -553,6 +553,23 @@ public Awaitable ConfigureAwait(bool continueOnCapturedContext)
         return default(Awaitable);
     }
 }
+");
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.ConfigureAwait)]
+    public async Task TestNoDiagnostic_ConfigureAwaitTrue()
+    {
+        await VerifyNoDiagnosticAsync(@"
+using System.Threading.Tasks;
+
+class C
+{
+    async Task M()
+    {
+        Task task = default;
+        await task.ConfigureAwait(true);
+    }
+}
 ");
     }
 }