Handle CurrentDispatcher.Invoke

Fix #194

Author: JohanLarsson

IDisposableAnalyzers.Test/IDISP004DoNotIgnoreCreatedTests/Valid.cs

@@ -771,5 +771,24 @@ public void Dispose()
 }".AssertReplace("await Task.FromResult(File.OpenRead(fileName))", statement);
             RoslynAssert.Valid(Analyzer, code);
         }
+
+        [Test]
+        public static void DispatcherInvoke()
+        {
+            var code = @"
+namespace N
+{
+    using System.Threading.Tasks;
+
+    public sealed class C
+    {
+        public async Task M()
+        {
+            await System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke(() => Task.FromResult(42)).ConfigureAwait(false);
+        }
+    }
+}";
+            RoslynAssert.Valid(Analyzer, code);
+        }
     }
 }

IDisposableAnalyzers/Helpers/Disposable.IsCreation.cs

@@ -89,26 +89,24 @@ internal static Result IsAlreadyAssignedWithCreated(ExpressionSyntax disposable,
                 return Result.No;
             }
 
-            using (var assignedValues = AssignedValueWalker.Borrow(disposable, semanticModel, cancellationToken))
+            using var assignedValues = AssignedValueWalker.Borrow(disposable, semanticModel, cancellationToken);
+            assignedSymbol = assignedValues.CurrentSymbol;
+            if (assignedValues.Count == 1 &&
+                disposable.Parent is AssignmentExpressionSyntax { Parent: ParenthesizedExpressionSyntax { Parent: BinaryExpressionSyntax { } binary } } &&
+                binary.IsKind(SyntaxKind.CoalesceExpression))
             {
-                assignedSymbol = assignedValues.CurrentSymbol;
-                if (assignedValues.Count == 1 &&
-                    disposable.Parent is AssignmentExpressionSyntax { Parent: ParenthesizedExpressionSyntax { Parent: BinaryExpressionSyntax { } binary } } &&
-                    binary.IsKind(SyntaxKind.CoalesceExpression))
-                {
-                    // lazy
-                    return Result.No;
-                }
-
-                if (symbol.IsEither<IParameterSymbol, ILocalSymbol>())
-                {
-                    assignedValues.RemoveAll(x => IsReturnedBefore(x));
-                }
+                // lazy
+                return Result.No;
+            }
 
-                using var recursive = RecursiveValues.Borrow(assignedValues, semanticModel, cancellationToken);
-                return IsAnyCreation(recursive, semanticModel, cancellationToken);
+            if (symbol.IsEither<IParameterSymbol, ILocalSymbol>())
+            {
+                assignedValues.RemoveAll(x => IsReturnedBefore(x));
             }
 
+            using var recursive = RecursiveValues.Borrow(assignedValues, semanticModel, cancellationToken);
+            return IsAnyCreation(recursive, semanticModel, cancellationToken);
+
             bool IsReturnedBefore(ExpressionSyntax expression)
             {
                 if (expression.TryFirstAncestor(out BlockSyntax? block) &&
@@ -358,9 +356,10 @@ candidate is IParameterSymbol ||
                         return Result.No;
                     }
 
-                    if (method.ReturnType == KnownSymbol.TaskOfT)
+                    if (method.ReturnType is INamedTypeSymbol { IsGenericType: true } returnType &&
+                        method.ReturnType == KnownSymbol.TaskOfT)
                     {
-                        return method.TypeArguments.TrySingle(out var typeArg) &&
+                        return returnType.TypeArguments.TrySingle(out var typeArg) &&
                                IsAssignableFrom(typeArg, compilation)
                             ? Result.AssumeYes
                             : Result.No;

IDisposableAnalyzers/Helpers/Temp/MethodSymbolExt.cs

@@ -1,10 +1,8 @@
 namespace IDisposableAnalyzers
 {
     using System.Diagnostics.CodeAnalysis;
-    using System.Threading;
     using Gu.Roslyn.AnalyzerExtensions;
     using Microsoft.CodeAnalysis;
-    using Microsoft.CodeAnalysis.CSharp.Syntax;
 
     internal static class MethodSymbolExt
     {
@@ -23,17 +21,5 @@ internal static bool TryGetThisParameter(this IMethodSymbol method, [NotNullWhen
             parameter = null;
             return false;
         }
-
-        internal static bool IsType(this ObjectCreationExpressionSyntax objectCreation, QualifiedType type, SemanticModel semanticModel, CancellationToken cancellationToken)
-        {
-            return objectCreation switch
-            {
-                { Type: IdentifierNameSyntax identifierName } => identifierName == type &&
-                                                                 semanticModel.TryGetType(objectCreation, cancellationToken, out var symbol) &&
-                                                                 symbol == type,
-                _ => semanticModel.TryGetType(objectCreation, cancellationToken, out var symbol) &&
-                     symbol == type,
-            };
-        }
     }
 }

IDisposableAnalyzers/Helpers/Temp/PooledSetExt.cs

@@ -69,6 +69,8 @@ public async Task Calls()
             }
 
             using var disposable2 = Task.FromResult(new Disposable()).Result;
+
+            await System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke(() => Task.FromResult(42)).ConfigureAwait(false);
         }
 
         public static async Task<string> Bar1Async()