Ignore Form.Show()

Close #187

Author: JohanLarsson

IDisposableAnalyzers.Test/Helpers/Disposable.Disposes.cs

@@ -148,7 +148,7 @@ internal C(string fileName)
             [Test]
             public static void WhenAddedToFormComponents()
             {
-                var code = @"
+                var syntaxTree = CSharpSyntaxTree.ParseText(@"
 namespace N
 {
     using System.IO;
@@ -163,14 +163,37 @@ public class Winform : Form
             this.components.Add(stream);
         }
     }
-}";
-                var syntaxTree = CSharpSyntaxTree.ParseText(code);
+}");
                 var compilation = CSharpCompilation.Create("test", new[] { syntaxTree }, MetadataReferences.FromAttributes());
                 var semanticModel = compilation.GetSemanticModel(syntaxTree);
                 var value = syntaxTree.FindVariableDeclaration("stream = File.OpenRead(string.Empty)");
                 Assert.AreEqual(true, semanticModel.TryGetSymbol(value, CancellationToken.None, out ILocalSymbol symbol));
                 Assert.AreEqual(true, Disposable.Disposes(symbol, semanticModel, CancellationToken.None));
             }
+
+            [Test]
+            public static void IgnoreNewFormShow()
+            {
+                var syntaxTree = CSharpSyntaxTree.ParseText(@"
+namespace N
+{
+    using System.Windows.Forms;
+
+    public class Winform : Form
+    {
+        public static void M()
+        {
+            var form = new Winform();
+            form.Show();
+        }
+    }
+}");
+                var compilation = CSharpCompilation.Create("test", new[] { syntaxTree }, MetadataReferences.FromAttributes());
+                var semanticModel = compilation.GetSemanticModel(syntaxTree);
+                var value = syntaxTree.FindVariableDeclaration("var form = new Winform()");
+                Assert.AreEqual(true, semanticModel.TryGetSymbol(value, CancellationToken.None, out ILocalSymbol symbol));
+                Assert.AreEqual(true, Disposable.Disposes(symbol, semanticModel, CancellationToken.None));
+            }
         }
     }
 }

IDisposableAnalyzers.Test/IDISP001DisposeCreatedTests/Valid.Winforms.cs

@@ -52,5 +52,33 @@ public class Winform : Form
 }".AssertReplace("this.components.Add(this.stream)", expression);
             RoslynAssert.NoAnalyzerDiagnostics(Analyzer, code);
         }
+
+        [Test]
+        public static void IgnoreNewFormShow()
+        {
+            var winForm = @"
+namespace N
+{
+    using System.Windows.Forms;
+
+    public class Winform : Form
+    {
+    }
+}";
+
+            var code = @"
+namespace N
+{
+    public class C
+    {
+        void M()
+        {
+            var form = new Winform();
+            form.Show();
+        }
+    }
+}";
+            RoslynAssert.NoAnalyzerDiagnostics(Analyzer, winForm, code);
+        }
     }
 }

IDisposableAnalyzers.sln.DotSettings

@@ -83,4 +83,5 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=struct/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Struct/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Tuple/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Winforms/@EntryIndexedValue">True</s:Boolean>
 </wpf:ResourceDictionary>

IDisposableAnalyzers/Helpers/Disposable.Disposes.cs

@@ -152,6 +152,9 @@ when Identity(candidate, recursion) is { } id &&
                 { Parent: ConditionalAccessExpressionSyntax { WhenNotNull: InvocationExpressionSyntax invocation } }
                 => IsDisposeOrReturnValueDisposed(invocation),
                 { Parent: MemberAccessExpressionSyntax { Parent: InvocationExpressionSyntax invocation } }
+                when invocation.IsSymbol(KnownSymbol.SystemWindowsFormsControl.Show, recursion.SemanticModel, recursion.CancellationToken)
+                => true, // disposed by form.Close()
+                { Parent: MemberAccessExpressionSyntax { Parent: InvocationExpressionSyntax invocation } }
                 => IsDisposeOrReturnValueDisposed(invocation),
                 { Parent: ConditionalAccessExpressionSyntax { } parent }
                 => DisposedByReturnValue(parent, recursion, out var creation) &&

IDisposableAnalyzers/Helpers/KnownSymbols/KnownSymbol.cs

@@ -67,6 +67,7 @@ internal static class KnownSymbol
 
         internal static readonly PasswordBoxType PasswordBox = new PasswordBoxType();
         internal static readonly QualifiedType SystemWindowsFormsForm = new QualifiedType("System.Windows.Forms.Form");
+        internal static readonly WinformsControlType SystemWindowsFormsControl = new WinformsControlType();
 
         internal static readonly QualifiedType NUnitSetUpAttribute = new QualifiedType("NUnit.Framework.SetUpAttribute");
         internal static readonly QualifiedType NUnitTearDownAttribute = new QualifiedType("NUnit.Framework.TearDownAttribute");

IDisposableAnalyzers/Helpers/KnownSymbols/WinformsControlType.cs

@@ -0,0 +1,15 @@
+namespace IDisposableAnalyzers
+{
+    using Gu.Roslyn.AnalyzerExtensions;
+
+    internal class WinformsControlType : QualifiedType
+    {
+        internal readonly QualifiedMethod Show;
+
+        internal WinformsControlType()
+            : base("System.Windows.Forms.Control")
+        {
+            this.Show = new QualifiedMethod(this, "Show");
+        }
+    }
+}