[Release/9.0] Fix false-positive WinForms Analyzer diagnostics.

src/System.Windows.Forms.Analyzers.CSharp/src/System/Windows/Forms/CSharp/Analyzers/MissingPropertySerializationConfiguration/MissingPropertySerializationConfigurationAnalyzer.cs

@@ -12,8 +12,8 @@ namespace System.Windows.Forms.CSharp.Analyzers.MissingPropertySerializationConf
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public class MissingPropertySerializationConfigurationAnalyzer : DiagnosticAnalyzer
 {
-    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics
-        => [CSharpDiagnosticDescriptors.s_missingPropertySerializationConfiguration];
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics =>
+        [CSharpDiagnosticDescriptors.s_missingPropertySerializationConfiguration];
 
     public override void Initialize(AnalysisContext context)
     {
@@ -24,26 +24,52 @@ public override void Initialize(AnalysisContext context)
 
     private static void AnalyzeSymbol(SymbolAnalysisContext context)
     {
-        // We analyze only properties.
-        var propertySymbol = (IPropertySymbol)context.Symbol;
+        // We only care about properties, and don't care about static properties.
+        if (context.Symbol is not IPropertySymbol propertySymbol
+            || propertySymbol.IsStatic)
+        {
+            return;
+        }
+
+        // A property of System.ComponentModel.ISite we never flag.
+        if (propertySymbol.Type.Name == nameof(ISite)
+            && propertySymbol.Type.ContainingNamespace.ToString() == "System.ComponentModel")
+        {
+            return;
+        }
 
-        // Does the property belong to a class which derives from Component?
+        // If the property is part of any interface named IComponent, we're out.
+        if (propertySymbol.ContainingType.Name == nameof(IComponent))
+        {
+            return;
+        }
+
+        // Does the property belong to a class which implements the System.ComponentModel.IComponent interface?
         if (propertySymbol.ContainingType is null
             || !propertySymbol
                 .ContainingType
                 .AllInterfaces
-                .Any(i => i.Name == nameof(IComponent)))
+                .Any(i => i.Name == nameof(IComponent) &&
+                          i.ContainingNamespace is not null &&
+                          i.ContainingNamespace.ToString() == "System.ComponentModel"))
         {
             return;
         }
 
-        // Is the property read/write and at least internal?
-        if (propertySymbol.SetMethod is null
+        // Is the property read/write and at least internal and doesn't have a private setter?
+        if (propertySymbol.SetMethod is not IMethodSymbol propertySetter
+            || propertySetter.DeclaredAccessibility == Accessibility.Private
             || propertySymbol.DeclaredAccessibility < Accessibility.Internal)
         {
             return;
         }
 
+        // Skip overridden properties since the base property should already have the appropriate serialization configuration
+        if (propertySymbol.IsOverride)
+        {
+            return;
+        }
+
         // Is the property attributed with DesignerSerializationVisibility or DefaultValue?
         if (propertySymbol.GetAttributes()
             .Any(a => a?.AttributeClass?.Name is (nameof(DesignerSerializationVisibilityAttribute))

src/System.Windows.Forms.Analyzers.VisualBasic/src/Analyzers/MissingPropertySerializationConfiguration/MissingPropertySerializationConfigurationDiagnosticAnalyzer.vb

@@ -32,18 +32,40 @@ Namespace Global.System.Windows.Forms.VisualBasic.Analyzers.MissingPropertySeria
                 Return
             End If
 
-            ' Does the property belong to a class which derives from Component?
+            ' A property of System.ComponentModel.ISite we never flag.
+            If propertySymbol.Type.Name = NameOf(ISite) AndAlso
+               propertySymbol.Type.ContainingNamespace.ToString() = "System.ComponentModel" Then
+                Return
+            End If
+
+            ' If the property is part of any interface named IComponent, we're out.
+            If propertySymbol.ContainingType.Name = NameOf(IComponent) Then
+                Return
+            End If
+
+            ' Does the property belong to a class which implements the System.ComponentModel.IComponent interface?
             If propertySymbol.ContainingType Is Nothing OrElse
                Not propertySymbol.ContainingType.AllInterfaces.Any(
-                Function(i) i.Name = NameOf(IComponent)) Then
+                Function(i) i.Name = NameOf(IComponent) AndAlso
+                          i.ContainingNamespace IsNot Nothing AndAlso
+                          i.ContainingNamespace.ToString() = "System.ComponentModel") Then
+                Return
+            End If
 
+            ' Skip static properties since they are not serialized by the designer
+            If propertySymbol.IsStatic Then
                 Return
             End If
 
-            ' Is the property read/write and at least internal?
+            ' Is the property read/write, at least internal, and doesn't have a private setter?
             If propertySymbol.SetMethod Is Nothing OrElse
+               propertySymbol.SetMethod.DeclaredAccessibility = Accessibility.Private OrElse
                propertySymbol.DeclaredAccessibility < Accessibility.Internal Then
+                Return
+            End If
 
+            ' Skip overridden properties since the base property should already have the appropriate serialization configuration
+            If propertySymbol.IsOverride Then
                 Return
             End If