BlockingCallInsideAsync Analyzer: Stop suggesting async calls from non-system assemblies

Author: semihokur

AsyncFixer.Test/BlockingCallInsideAsyncTests.cs

@@ -167,7 +167,7 @@ async Task foo()
         }
 
         [Fact]
-        public void BlockingCallInsideAsyncTest5()
+        public void NoWarn_BlockingCallInsideAsyncTest5()
         {
             var test = @"
 using System;
@@ -191,83 +191,7 @@ public Task<int> booAsync(int a)
     }
 }";
 
-            var expected = new DiagnosticResult { Id = DiagnosticIds.BlockingCallInsideAsync };
-            VerifyCSharpDiagnostic(test, expected);
-
-            var fixtest = @"
-using System;
-using System.Threading.Tasks;
-
-class Program
-{
-    async Task foo()
-    {
-        // comment
-        await this.booAsync(0);
-        // end comment
-    }
-    public int boo(int a)
-    {
-        return 3;
-    }
-    public Task<int> booAsync(int a)
-    {
-        return Task.Run(()=>4);
-    }
-}";
-
-            VerifyCSharpFix(test, fixtest);
-        }
-
-        [Fact]
-        public void BlockingCallInsideAsyncTest6()
-        {
-            var test = @"
-using System;
-using System.Threading.Tasks;
-
-class Program
-{
-    async Task foo()
-    {
-        // comment
-        boo(0);
-    }
-    public int boo(int a)
-    {
-        return 3;
-    }
-    public async Task<int> booAsync(int a)
-    {
-        return a;
-    }
-}";
-
-            var expected = new DiagnosticResult { Id = DiagnosticIds.BlockingCallInsideAsync };
-            VerifyCSharpDiagnostic(test, expected);
-
-            var fixtest = @"
-using System;
-using System.Threading.Tasks;
-
-class Program
-{
-    async Task foo()
-    {
-        // comment
-        await booAsync(0);
-    }
-    public int boo(int a)
-    {
-        return 3;
-    }
-    public async Task<int> booAsync(int a)
-    {
-        return a;
-    }
-}";
-
-            VerifyCSharpFix(test, fixtest);
+            VerifyCSharpDiagnostic(test);
         }
 
         [Fact]
@@ -302,54 +226,6 @@ async Task foo()
             VerifyCSharpFix(test, fixtest);
         }
 
-        [Fact]
-        public void BlockingCallInsideAsyncTest8()
-        {
-            var test = @"
-using System;
-using System.Threading.Tasks;
-
-class Program
-{
-    async Task foo()
-    {
-        boo(0);
-    }
-    int boo(int a)
-    {
-        return a;
-    }
-    async Task<int> booAsync(int a)
-    {
-        return 3;
-    }
-}";
-            var expected = new DiagnosticResult { Id = DiagnosticIds.BlockingCallInsideAsync };
-            VerifyCSharpDiagnostic(test, expected);
-
-            var fixtest = @"
-using System;
-using System.Threading.Tasks;
-
-class Program
-{
-    async Task foo()
-    {
-        await booAsync(0);
-    }
-    int boo(int a)
-    {
-        return a;
-    }
-    async Task<int> booAsync(int a)
-    {
-        return 3;
-    }
-}";
-
-            VerifyCSharpFix(test, fixtest);
-        }
-
         [Fact]
         public void BlockingCallInsideAsyncTest9()
         {

AsyncFixer.Test/NestedTaskToOuterTaskTests.cs

@@ -100,6 +100,29 @@ TaskCanceledException foo()
             VerifyCSharpDiagnostic(test);
         }
 
+        [Fact]
+        public void GenericTaskType()
+        {
+            var test = @"
+using System.Threading.Tasks;
+
+class Program
+{
+    async void main()
+    {
+        await Task.Factory.StartNew(() => foo());
+    }
+
+    Task<int> foo()
+    {
+        return Task.FromResult(3);
+    }
+}";
+
+            var expected = new DiagnosticResult { Id = DiagnosticIds.NestedTaskToOuterTask };
+            VerifyCSharpDiagnostic(test, expected);
+        }
+
         protected override DiagnosticAnalyzer GetCSharpDiagnosticAnalyzer()
         {
             return new NestedTaskToOuterTaskAnalyzer();

AsyncFixer/BlockingCallInsideAsync/BlockingCallInsideAsyncAnalyzer.cs

@@ -125,15 +125,21 @@ private void AnalyzeMemberAccess(SyntaxNodeAnalysisContext context, MethodDeclar
 
         private static string DetectSynchronousUsages(Location location, IMethodSymbol methodCallSymbol, SemanticModel semanticModel)
         {
-            var methodName = methodCallSymbol.Name;
-
-            var typeName = methodCallSymbol.ContainingType.Name;
-
             if (methodCallSymbol.ContainingType == null)
             {
                 return null;
             }
 
+            if (!methodCallSymbol.ContainingAssembly.ToDisplayString().StartsWith("System.", StringComparison.OrdinalIgnoreCase))
+            {
+                // Only look at the symbols from the System assemblies.
+                return null;
+            }
+
+            var methodName = methodCallSymbol.Name;
+
+            var typeName = methodCallSymbol.ContainingType.Name;
+
             if (typeName == "MemoryStream")
             {
                 // Do not replace the synchronous ones under MemoryStream.

AsyncFixer/Helpers.cs

@@ -21,12 +21,13 @@ public static bool IsTaskCreationMethod(this IMethodSymbol symbol)
 
         public static bool IsTask(this ITypeSymbol type)
         {
-            return type.ToDisplayString().StartsWith("System.Threading.Tasks.Task", StringComparison.OrdinalIgnoreCase);
+            return type.ContainingNamespace.ToDisplayString() == "System.Threading.Tasks" &&
+                type.Name == "Task";
         }
 
         public static bool ReturnTask(this IMethodSymbol symbol)
         {
-            return !symbol.ReturnsVoid && symbol.ReturnType.ToString().StartsWith("System.Threading.Tasks.Task", StringComparison.OrdinalIgnoreCase);
+            return !symbol.ReturnsVoid && symbol.ReturnType.IsTask();
         }
 
         public static bool IsAsync(this MethodDeclarationSyntax method)