Merge pull request #1245 from AArnott/fix1168

Fix VSTHRD110 to not misfire due to parentheses in invocation expressions
microsoft · Oct 24, 2023 · 8a79cb7 · 8a79cb7
2 parents a74e8e8 + dc30848
commit 8a79cb7
Show file tree

Hide file tree

Showing 2 changed files with 42 additions and 5 deletions.
diff --git a/...ft.VisualStudio.Threading.Analyzers/AbstractVSTHRD110ObserveResultOfAsyncCallsAnalyzer.cs b/...ft.VisualStudio.Threading.Analyzers/AbstractVSTHRD110ObserveResultOfAsyncCallsAnalyzer.cs
@@ -57,14 +57,33 @@ private void AnalyzeInvocation(OperationAnalysisContext context, CommonInterest.
             return;
         }
 
-        // Only consider invocations that are direct statements. Otherwise, we assume their
-        // result is awaited, assigned, or otherwise consumed.
-        if (operation.Parent is IExpressionStatementOperation || operation.Parent is IConditionalAccessOperation)
+        // Only consider invocations that are direct statements (or are statements through limited steps).
+        // Otherwise, we assume their result is awaited, assigned, or otherwise consumed.
+        IOperation? parentOperation = operation.Parent;
+        while (parentOperation is not null)
         {
-            if (awaitableTypes.IsAwaitableType(operation.Type))
+            if (parentOperation is IExpressionStatementOperation)
             {
-                context.ReportDiagnostic(Diagnostic.Create(Descriptor, operation.Syntax.GetLocation()));
+                // This expression is directly used in a statement.
+                break;
             }
+
+            // This check is where we allow for specific operation types that may appear between the invocation
+            // and the statement that don't disqualify the invocation search for an invalid pattern.
+            if (parentOperation is IConditionalAccessOperation)
+            {
+                parentOperation = parentOperation.Parent;
+            }
+            else
+            {
+                // This expression is not directly used in a statement.
+                return;
+            }
+        }
+
+        if (awaitableTypes.IsAwaitableType(operation.Type))
+        {
+            context.ReportDiagnostic(Diagnostic.Create(Descriptor, operation.Syntax.GetLocation()));
         }
     }
 }
diff --git a/...VisualStudio.Threading.Analyzers.Tests/VSTHRD110ObserveResultOfAsyncCallsAnalyzerTests.cs b/...VisualStudio.Threading.Analyzers.Tests/VSTHRD110ObserveResultOfAsyncCallsAnalyzerTests.cs
@@ -453,6 +453,24 @@ public async ValueTask DisposeAsync()
         await CSVerify.VerifyAnalyzerAsync(test);
     }
 
+    [Fact]
+    public async Task ParentheticalUseOfTaskResult_ProducesNoDiagnostic()
+    {
+        string test = """
+            using System;
+            using System.Threading.Tasks;
+
+            class Class1
+            {
+                public Func<Task<int>>? VCLoadMethod;
+
+                public int? VirtualCurrencyBalances => (VCLoadMethod?.Invoke()).GetAwaiter().GetResult();
+            }
+            """;
+
+        await CSVerify.VerifyAnalyzerAsync(test);
+    }
+
     private DiagnosticResult CreateDiagnostic(int line, int column, int length)
         => CSVerify.Diagnostic().WithSpan(line, column, line, column + length);
 }