Fixes microsoft#772. VSTHRD110 now detects a ConditionalAccessExpress…

…ionSyntax parent of the invocation.
bluetarpmedia · Jun 16, 2021 · f8406d0 · f8406d0
1 parent 94e1337
commit f8406d0
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Showing 2 changed files with 40 additions and 1 deletion.
diff --git a/...oft.VisualStudio.Threading.Analyzers.CSharp/VSTHRD110ObserveResultOfAsyncCallsAnalyzer.cs b/...oft.VisualStudio.Threading.Analyzers.CSharp/VSTHRD110ObserveResultOfAsyncCallsAnalyzer.cs
@@ -46,7 +46,7 @@ internal void AnalyzeInvocation(SyntaxNodeAnalysisContext context)
 
                 // Only consider invocations that are direct statements. Otherwise, we assume their
                 // result is awaited, assigned, or otherwise consumed.
-                if (invocation.Parent?.GetType().Equals(typeof(ExpressionStatementSyntax)) ?? false)
+                if (invocation.Parent is ExpressionStatementSyntax || invocation.Parent is ConditionalAccessExpressionSyntax)
                 {
                     var methodSymbol = context.SemanticModel.GetSymbolInfo(context.Node).Symbol as IMethodSymbol;
                     if (this.IsAwaitableType(methodSymbol?.ReturnType, context.Compilation, context.CancellationToken))

diff --git a/...VisualStudio.Threading.Analyzers.Tests/VSTHRD110ObserveResultOfAsyncCallsAnalyzerTests.cs b/...VisualStudio.Threading.Analyzers.Tests/VSTHRD110ObserveResultOfAsyncCallsAnalyzerTests.cs
@@ -363,6 +363,45 @@ void Foo()
             await Verify.VerifyAnalyzerAsync(test, expected);
         }
 
+        [Fact]
+        public async Task ConditionalAccess_ProducesDiagnostic()
+        {
+            var test = @"
+using System.Threading.Tasks;
+
+class Test {
+    void Foo(Test? tester)
+    {
+        tester?.BarAsync();
+    }
+
+    Task BarAsync() => null;
+}
+";
+
+            DiagnosticResult expected = this.CreateDiagnostic(7, 17, 8);
+            await Verify.VerifyAnalyzerAsync(test, expected);
+        }
+
+        [Fact]
+        public async Task ConditionalAccessAwaited_ProducesNoDiagnostic()
+        {
+            var test = @"
+using System.Threading.Tasks;
+
+class Test {
+    async Task Foo(Test? tester)
+    {
+        await (tester?.BarAsync() ?? Task.CompletedTask);
+    }
+
+    Task BarAsync() => null;
+}
+";
+
+            await Verify.VerifyAnalyzerAsync(test);
+        }
+
         private DiagnosticResult CreateDiagnostic(int line, int column, int length)
             => Verify.Diagnostic().WithSpan(line, column, line, column + length);
     }