Finish enabling unnecessary assignment analyzer (#12534)

Now is enabled as a warning again and will fail the command line build.
Removes last TODOs from .editorconfig

.editorconfig

@@ -264,7 +264,7 @@ dotnet_diagnostic.IDE0057.severity = suggestion
 dotnet_diagnostic.IDE0058.severity = silent
 
 # IDE0059: Unnecessary assignment of a value
-dotnet_diagnostic.IDE0059.severity = suggestion # TODO: warning
+dotnet_diagnostic.IDE0059.severity = warning
 
 # IDE0060: Remove unused parameter
 dotnet_diagnostic.IDE0060.severity = silent
@@ -708,7 +708,7 @@ dotnet_diagnostic.CA1819.severity = none
 dotnet_diagnostic.CA1820.severity = none
 
 # CA1821: Remove empty Finalizers
-dotnet_diagnostic.CA1821.severity = none # TODO: warning
+dotnet_diagnostic.CA1821.severity = warning
 
 # CA1822: Mark members as static
 dotnet_diagnostic.CA1822.severity = warning
@@ -1523,8 +1523,8 @@ dotnet_diagnostic.SA1204.severity = none
 # SA1205: Partial elements should declare an access modifier
 dotnet_diagnostic.SA1205.severity = warning
 
-# SA1206: Keyword ordering - TODO Re-enable as warning after https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3527
-dotnet_diagnostic.SA1206.severity = suggestion
+# SA1206: Keyword ordering
+dotnet_diagnostic.SA1206.severity = warning
 
 # SA1207: Protected should come before internal
 dotnet_diagnostic.SA1207.severity = none

src/Microsoft.VisualBasic.Forms/tests/UnitTests/System/Windows/Forms/VbFileCleanupTestBaseTests.vb

@@ -14,9 +14,9 @@ Namespace Microsoft.VisualBasic.Forms.Tests
         Public Sub CreateTempDirectoryTest()
             Dim tempDirectory As String = CreateTempDirectory()
             tempDirectory.Should.StartWith(Path.GetTempPath)
-            tempDirectory = CreateTempDirectory()
+            CreateTempDirectory()
             _testDirectories.Count.Should.Be(1)
-            tempDirectory = CreateTempDirectory(lineNumber:=1)
+            CreateTempDirectory(lineNumber:=1)
             _testDirectories.Count.Should.Be(2)
         End Sub
 

src/System.Drawing.Common/tests/System/Drawing/Printing/PrinterSettingsTests.cs

@@ -43,14 +43,14 @@ public void Ctor_Default_Success()
     public void CanDuplex_ReturnsExpected()
     {
         PrinterSettings printerSettings = new();
-        bool canDuplex = printerSettings.CanDuplex;
+        _ = printerSettings.CanDuplex;
     }
 
     [Fact]
     public void Copies_Default_ReturnsExpected()
     {
         PrinterSettings printerSettings = new();
-        int copies = printerSettings.Copies;
+        _ = printerSettings.Copies;
     }
 
     [Theory]
@@ -79,7 +79,7 @@ public void Copies_SetValue_ThrowsArgumentException(short copies)
     public void Collate_Default_ReturnsExpected()
     {
         PrinterSettings printerSettings = new();
-        bool collate = printerSettings.Collate;
+        _ = printerSettings.Collate;
     }
 
     [Fact]
@@ -380,7 +380,7 @@ public static IEnumerable<object[]> IsDirectPrintingSupported_ImageFormatSupport
     public void IsDirectPrintingSupported_ImageFormatSupported_ReturnsExpected(ImageFormat imageFormat)
     {
         PrinterSettings printerSettings = new();
-        bool supported = printerSettings.IsDirectPrintingSupported(imageFormat);
+        _ = printerSettings.IsDirectPrintingSupported(imageFormat);
     }
 
     public static IEnumerable<object[]> IsDirectPrintingSupported_ImageFormatNotSupported_TestData()
@@ -508,21 +508,17 @@ public void CreateMeasurementGraphics_Null_ThrowsNullReferenceException()
     public void GetHdevmode_ReturnsExpected()
     {
         PrinterSettings printerSettings = new();
-        IntPtr handle = IntPtr.Zero;
-
-        handle = printerSettings.GetHdevmode();
-        Assert.NotEqual(IntPtr.Zero, handle);
+        nint handle = printerSettings.GetHdevmode();
+        Assert.NotEqual(0, handle);
     }
 
     [Fact]
     public void GetHdevmode_PageSettings_ReturnsExpected()
     {
         PrinterSettings printerSettings = new();
         PageSettings pageSettings = new();
-        IntPtr handle = IntPtr.Zero;
-
-        handle = printerSettings.GetHdevmode(pageSettings);
-        Assert.NotEqual(IntPtr.Zero, handle);
+        nint handle = printerSettings.GetHdevmode(pageSettings);
+        Assert.NotEqual(0, handle);
     }
 
     [Fact]
@@ -536,10 +532,8 @@ public void GetHdevmode_Null_ThrowsNullReferenceException()
     public void GetHdevnames_ReturnsExpected()
     {
         PrinterSettings printerSettings = new();
-        IntPtr handle = IntPtr.Zero;
-
-        handle = printerSettings.GetHdevnames();
-        Assert.NotEqual(IntPtr.Zero, handle);
+        nint handle = printerSettings.GetHdevnames();
+        Assert.NotEqual(0, handle);
     }
 
     [ConditionalFact(typeof(PrinterSettingsTests), nameof(CanTestSetHdevmode_IntPtr_Success))]

src/System.Drawing.Common/tests/mono/System.Drawing/GraphicsTests.cs

@@ -83,7 +83,7 @@ private static void CheckForEmptyBitmap(Bitmap bitmap)
 
     private static void CheckForNonEmptyBitmap(Bitmap bitmap)
     {
-        if (IsEmptyBitmap(bitmap, out int x, out int y))
+        if (IsEmptyBitmap(bitmap, out int _, out int _))
             Assert.True(false);
     }
 

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/Serialization/CodeDomSerializer.cs

@@ -293,49 +293,49 @@ public virtual CodeStatementCollection SerializeMemberAbsolute(IDesignerSerializ
     [Obsolete("This method has been deprecated. Use SerializeToExpression or GetExpression instead.  https://go.microsoft.com/fwlink/?linkid=14202")]
     protected CodeExpression? SerializeToReferenceExpression(IDesignerSerializationManager manager, object value)
     {
-        CodeExpression? expression = null;
-
         // First - try GetExpression
-        expression = GetExpression(manager, value);
+        if (GetExpression(manager, value) is { } expression)
+        {
+            return expression;
+        }
+
+        if (value is not IComponent)
+        {
+            return null;
+        }
+
         // Next, we check for a named IComponent, and return a reference to it.
-        if (expression is null && value is IComponent)
+        string? name = manager.GetName(value);
+        bool referenceName = false;
+        if (name is null)
         {
-            string? name = manager.GetName(value);
-            bool referenceName = false;
-            if (name is null)
+            IReferenceService? referenceService = manager.GetService<IReferenceService>();
+            if (referenceService is not null)
             {
-                IReferenceService? referenceService = manager.GetService<IReferenceService>();
-                if (referenceService is not null)
-                {
-                    name = referenceService.GetName(value);
-                    referenceName = name is not null;
-                }
+                name = referenceService.GetName(value);
+                referenceName = name is not null;
             }
+        }
 
-            if (name is not null)
-            {
-                // Check to see if this is a reference to the root component. If it is, then use "this".
-                if (manager.TryGetContext(out RootContext? root) && root.Value == value)
-                {
-                    expression = root.Expression;
-                }
-                else
-                {
-                    int dotIndex = name.IndexOf('.');
-                    if (referenceName && dotIndex != -1)
-                    {
-                        // if it's a reference name with a dot, we've actually got a property here...
-                        expression = new CodePropertyReferenceExpression(new CodeFieldReferenceExpression(s_thisRef, name[..dotIndex]), name[(dotIndex + 1)..]);
-                    }
-                    else
-                    {
-                        expression = new CodeFieldReferenceExpression(s_thisRef, name);
-                    }
-                }
-            }
+        if (name is null)
+        {
+            return null;
+        }
+
+        // Check to see if this is a reference to the root component. If it is, then use "this".
+        if (manager.TryGetContext(out RootContext? root) && root.Value == value)
+        {
+            return root.Expression;
         }
 
-        return expression;
+        // If it's a reference name with a dot, we've actually got a property.
+
+        int dotIndex = name.IndexOf('.');
+        return referenceName && dotIndex != -1
+            ? new CodePropertyReferenceExpression(
+                new CodeFieldReferenceExpression(s_thisRef, name[..dotIndex]),
+                name[(dotIndex + 1)..])
+            : new CodeFieldReferenceExpression(s_thisRef, name);
     }
 
     private static void ResetBrowsableProperties(object? instance)

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/Serialization/DesignerSerializationManager.cs

@@ -485,7 +485,7 @@ public IDisposable CreateSession()
         // Check for a default serialization provider
         if (_defaultProviderTable is null || !_defaultProviderTable.Contains(serializerType))
         {
-            Type? defaultSerializerType = null;
+            Type? defaultSerializerType;
             DefaultSerializationProviderAttribute? attribute = (DefaultSerializationProviderAttribute?)TypeDescriptor.GetAttributes(serializerType)[typeof(DefaultSerializationProviderAttribute)];
             if (attribute is not null)
             {

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/Serialization/EnumCodeDomSerializer.cs

@@ -30,13 +30,13 @@ public override object Serialize(IDesignerSerializationManager manager, object?
             return null!;
         }
 
-        bool needCast = false;
+        bool needCast;
         Enum[] values;
         TypeConverter? converter = TypeDescriptor.GetConverter(enumValue);
         if (converter is not null && converter.CanConvertTo(typeof(Enum[])))
         {
             values = (Enum[])converter.ConvertTo(enumValue, typeof(Enum[]))!;
-            needCast = (values.Length > 1);
+            needCast = values.Length > 1;
         }
         else
         {

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/Serialization/TypeCodeDomSerializer.cs

@@ -214,7 +214,7 @@ public virtual object Deserialize(IDesignerSerializationManager manager, CodeTyp
     /// </summary>
     private object? DeserializeName(IDesignerSerializationManager manager, string name, CodeStatementCollection? statements)
     {
-        object? value = null;
+        object? value;
 
         // If the name we're looking for isn't in our dictionary, we return null.
         // It is up to the caller to decide if this is an error or not.

src/System.Windows.Forms.Design/src/System/Drawing/Design/ImageEditor.cs

@@ -62,7 +62,7 @@ protected static string CreateFilterEntry(ImageEditor e)
 
     public override object? EditValue(ITypeDescriptorContext? context, IServiceProvider provider, object? value)
     {
-        if (!provider.TryGetService(out IWindowsFormsEditorService? editorService))
+        if (!provider.TryGetService(out IWindowsFormsEditorService? _))
         {
             return value;
         }
@@ -86,6 +86,7 @@ protected static string CreateFilterEntry(ImageEditor e)
                     binder: null,
                     args: null,
                     culture: null);
+
                 if (editor is not null
                     && editor.GetType() is Type editorClass
                     && !myClass.Equals(editorClass)
@@ -118,7 +119,6 @@ protected static string CreateFilterEntry(ImageEditor e)
         return value;
     }
 
-    /// <inheritdoc />
     public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext? context) => UITypeEditorEditStyle.Modal;
 
     protected virtual string GetFileDialogDescription() => SR.imageFileDescription;

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/Behavior/ToolStripPanelSelectionGlyph.cs

@@ -98,8 +98,8 @@ private void SetBitmap(string fileName)
     private void CollapseGlyph(Rectangle bounds)
     {
         DockStyle? dock = _relatedPanel?.Dock;
-        int x = 0;
-        int y = 0;
+        int x;
+        int y;
 
         switch (dock)
         {
@@ -147,8 +147,8 @@ private void CollapseGlyph(Rectangle bounds)
     private void ExpandGlyph(Rectangle bounds)
     {
         DockStyle? dock = _relatedPanel?.Dock;
-        int x = 0;
-        int y = 0;
+        int x;
+        int y;
 
         switch (dock)
         {

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ControlCodeDomSerializer.cs

@@ -334,45 +334,58 @@ private static Type[] ToTargetTypes(object context, Type[] runtimeTypes)
     /// <summary>
     ///  Serializes a method invocation on the control being serialized. Used to serialize Suspend/ResumeLayout pairs, etc.
     /// </summary>
-    private void SerializeMethodInvocation(IDesignerSerializationManager manager, CodeStatementCollection statements, object control, string methodName, CodeExpressionCollection? parameters, Type[] paramTypes, StatementOrdering ordering)
+    private void SerializeMethodInvocation(
+        IDesignerSerializationManager manager,
+        CodeStatementCollection statements,
+        object control,
+        string methodName,
+        CodeExpressionCollection? parameters,
+        Type[] paramTypes,
+        StatementOrdering ordering)
     {
-        string? name = manager.GetName(control);
+        // Not doing anything with the name, keeping the access for compat.
+        _ = manager.GetName(control);
 
         // Use IReflect to see if this method name exists on the control.
         paramTypes = ToTargetTypes(control, paramTypes);
-        MethodInfo? mi = TypeDescriptor.GetReflectionType(control).GetMethod(methodName, BindingFlags.Public | BindingFlags.Instance, binder: null, paramTypes, modifiers: null);
-
-        if (mi is not null)
+        if (TypeDescriptor.GetReflectionType(control).GetMethod(
+            methodName,
+            BindingFlags.Public | BindingFlags.Instance,
+            binder: null,
+            paramTypes,
+            modifiers: null) is null)
         {
-            CodeExpression? field = SerializeToExpression(manager, control);
-            CodeMethodReferenceExpression method = new(field, methodName);
-            CodeMethodInvokeExpression methodInvoke = new()
-            {
-                Method = method
-            };
+            return;
+        }
 
-            if (parameters is not null)
-            {
-                methodInvoke.Parameters.AddRange(parameters);
-            }
+        CodeExpression? field = SerializeToExpression(manager, control);
+        CodeMethodReferenceExpression method = new(field, methodName);
+        CodeMethodInvokeExpression methodInvoke = new()
+        {
+            Method = method
+        };
 
-            CodeExpressionStatement statement = new(methodInvoke);
+        if (parameters is not null)
+        {
+            methodInvoke.Parameters.AddRange(parameters);
+        }
 
-            switch (ordering)
-            {
-                case StatementOrdering.Prepend:
-                    statement.UserData["statement-ordering"] = "begin";
-                    break;
-                case StatementOrdering.Append:
-                    statement.UserData["statement-ordering"] = "end";
-                    break;
-                default:
-                    Debug.Fail($"Unsupported statement ordering: {ordering}");
-                    break;
-            }
+        CodeExpressionStatement statement = new(methodInvoke);
 
-            statements.Add(statement);
+        switch (ordering)
+        {
+            case StatementOrdering.Prepend:
+                statement.UserData["statement-ordering"] = "begin";
+                break;
+            case StatementOrdering.Append:
+                statement.UserData["statement-ordering"] = "end";
+                break;
+            default:
+                Debug.Fail($"Unsupported statement ordering: {ordering}");
+                break;
         }
+
+        statements.Add(statement);
     }
 
     private void SerializePerformLayout(IDesignerSerializationManager manager, CodeStatementCollection statements, object control)

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ControlDesigner.cs

@@ -1665,7 +1665,7 @@ protected override void PreFilterProperties(IDictionary properties)
     }
 
     /// <summary>
-    ///  Hooks the children of the given control. We need to do this for child controls that are not in design
+    ///  Unhooks the children of the given control. We need to do this for child controls that are not in design
     ///  mode, which is the case for composite controls.
     /// </summary>
     protected void UnhookChildControls(Control firstChild)
@@ -1674,11 +1674,9 @@ protected void UnhookChildControls(Control firstChild)
 
         foreach (Control child in firstChild.Controls)
         {
-            IWindowTarget? oldTarget = null;
             if (child is not null)
             {
-                // No, no designer means we must replace the window target in this control.
-                oldTarget = child.WindowTarget;
+                IWindowTarget? oldTarget = child.WindowTarget;
                 if (oldTarget is ChildWindowTarget target)
                 {
                     child.WindowTarget = target.OldWindowTarget;