Special case GetAsFrozen

Fix #354

Author: JohanLarsson

WpfAnalyzers.Test/WPF0010DefaultValueMustMatchRegisteredTypeTests/Valid.cs

@@ -522,6 +522,40 @@ internal static object Box(bool value)
         RoslynAssert.Valid(Analyzer, code);
     }
 
+    [Test]
+    public static void FrozenGeometry()
+    {
+        var code = @"
+namespace N
+{
+    using System.Windows;
+    using System.Windows.Controls;
+    using System.Windows.Media;
+
+    public class C : Control
+    {
+        public static readonly DependencyProperty GeometryProperty = DependencyProperty.Register(
+            nameof(Geometry),
+            typeof(Geometry),
+            typeof(C),
+            new PropertyMetadata(Default()));
+
+        public Geometry? Geometry
+        {
+            get => (Geometry?)this.GetValue(GeometryProperty);
+            set => this.SetValue(GeometryProperty, value);
+        }
+
+        private static Freezable Default()
+        {
+            var geometry = new EllipseGeometry(default, 5, 5);
+            return geometry.GetAsFrozen();
+        }
+    }
+}";
+        RoslynAssert.Valid(Analyzer, code);
+    }
+
     [Test]
     public static void EnumIssue211()
     {

WpfAnalyzers/Helpers/PropertyMetaData.cs

@@ -83,8 +83,8 @@ internal ArgumentSyntax? CoerceValueArgument
     {
         if (objectCreation is { ArgumentList: { } })
         {
-            if (semanticModel.TryGetSymbol(objectCreation, KnownSymbols.PropertyMetadata,          cancellationToken, out var constructor) ||
-                semanticModel.TryGetSymbol(objectCreation, KnownSymbols.UIPropertyMetadata,        cancellationToken, out constructor) ||
+            if (semanticModel.TryGetSymbol(objectCreation, KnownSymbols.PropertyMetadata, cancellationToken, out var constructor) ||
+                semanticModel.TryGetSymbol(objectCreation, KnownSymbols.UIPropertyMetadata, cancellationToken, out constructor) ||
                 semanticModel.TryGetSymbol(objectCreation, KnownSymbols.FrameworkPropertyMetadata, cancellationToken, out constructor))
             {
                 return new PropertyMetadata(objectCreation, constructor);
@@ -152,7 +152,7 @@ static bool IsValueValidForRegisteredType(ExpressionSyntax value, ITypeSymbol re
             switch (value)
             {
                 case ConditionalExpressionSyntax { WhenTrue: { } whenTrue, WhenFalse: { } whenFalse }:
-                    return IsValueValidForRegisteredType(whenTrue,  registeredType, recursion) &&
+                    return IsValueValidForRegisteredType(whenTrue, registeredType, recursion) &&
                            IsValueValidForRegisteredType(whenFalse, registeredType, recursion);
 
                 case BinaryExpressionSyntax { Left: { }, Right: { } right } binary
@@ -201,6 +201,8 @@ when binary.IsKind(SyntaxKind.CoalesceExpression):
                         return IsAssignedValueOfRegisteredType(property, declaration);
                     case { Symbol: IMethodSymbol _, Declaration: MethodDeclarationSyntax declaration }:
                         return IsReturnValueOfRegisteredType(declaration);
+                    case { Symbol: IMethodSymbol { MetadataName: "GetAsFrozen" }, Source: InvocationExpressionSyntax { Expression: MemberAccessExpressionSyntax { Expression: { } expression } } }:
+                        return recursion.SemanticModel.IsRepresentationPreservingConversion(expression, registeredType);
                     case { Symbol: IFieldSymbol { Type: { SpecialType: SpecialType.System_Object } } }:
                         return true;
                     case { Symbol: IPropertySymbol { Type: { SpecialType: SpecialType.System_Object } } }: