Emit diagnostics even if default value is not constant

Author: Sergio0694

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators/Diagnostics/Analyzers/UseGeneratedDependencyPropertyOnManualPropertyAnalyzer.cs

@@ -736,19 +736,19 @@ void HandleSetAccessor(IPropertySymbol propertySymbol, PropertyFlags propertyFla
                                     // pretending this were the empty string literal instead. This way we can still support the property and convert to an attribute.
                                     fieldFlags.DefaultValue = TypedConstantInfo.Primitive.String.Empty;
                                 }
-                                else
+                                else if (fieldFlags.DefaultValueOperation is IDefaultValueOperation { Type: { } defaultValueExpressionType })
                                 {
-                                    // If we don't have a constant, check if it's some constant value we can forward. In this case, we
-                                    // did not retrieve it. As a last resort, check if this is explicitly a 'default(T)' expression.
-                                    if (fieldFlags.DefaultValueOperation is not IDefaultValueOperation { Type: { } defaultValueExpressionType })
-                                    {
-                                        continue;
-                                    }
-
-                                    // Store the expression type for later, so we can validate it. We cannot validate it from here, as we
-                                    // only see the declared property type for metadata. This isn't guaranteed to match the property type.
+                                    // We don't have a constant. As a last resort, check if this is explicitly a 'default(T)' expression.
+                                    // If so, store the expression type for later, so we can validate it. We cannot validate it here, as
+                                    // we still want to execute the rest of the checks below to potentially emit more diagnostics first.
                                     fieldFlags.DefaultValueExpressionType = defaultValueExpressionType;
                                 }
+                                else
+                                {
+                                    // At this point we know the property cannot possibly be converted, so mark it as invalid. We do this
+                                    // rather than returning immediately, to still allow more diagnostics to be produced in the steps below.
+                                    fieldFlags.HasAnyDiagnostics = true;
+                                }
                             }
                         }
 

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.Tests/Test_Analyzers.cs

@@ -2234,6 +2234,63 @@ public partial class MyControl : Control
         await CSharpAnalyzerTest<UseGeneratedDependencyPropertyOnManualPropertyAnalyzer>.VerifyAnalyzerAsync(source, LanguageVersion.CSharp13);
     }
 
+    // Regression test for a case found in the Microsoft Store
+    [TestMethod]
+    public async Task UseGeneratedDependencyPropertyOnManualPropertyAnalyzer_InvalidRegisterArguments_WCTDP0030_WithObjectInitialization_DoesNotWarn()
+    {
+       const string source = """
+            using Windows.UI.Xaml;
+            using Windows.UI.Xaml.Controls;
+            
+            namespace MyApp;
+
+            public partial class MyControl : Control
+            {
+                public static readonly DependencyProperty MarginProperty = DependencyProperty.Register(
+                    nameof(Margin),
+                    {|WCTDP0030:typeof(double)|},
+                    typeof(MyControl),
+                    new PropertyMetadata({|WCTDP0032:new Thickness(0)|}));
+
+                private Thickness Margin
+                {
+                    get => (Thickness)GetValue(MarginProperty);
+                    set => SetValue(MarginProperty, value);
+                }
+            }
+            """;
+
+        await CSharpAnalyzerTest<UseGeneratedDependencyPropertyOnManualPropertyAnalyzer>.VerifyAnalyzerAsync(source, LanguageVersion.CSharp13);
+    }
+
+    [TestMethod]
+    public async Task UseGeneratedDependencyPropertyOnManualPropertyAnalyzer_InvalidRegisterArguments_WCTDP0030_WithExplicitDefaultValueNull_DoesNotWarn()
+    {
+        const string source = """
+            using Windows.UI.Xaml;
+            using Windows.UI.Xaml.Controls;
+            
+            namespace MyApp;
+
+            public partial class MyControl : Control
+            {
+                public static readonly DependencyProperty MarginProperty = DependencyProperty.Register(
+                    nameof(Margin),
+                    {|WCTDP0030:typeof(double)|},
+                    typeof(MyControl),
+                    new PropertyMetadata({|WCTDP0031:null|}));
+
+                private Thickness Margin
+                {
+                    get => (Thickness)GetValue(MarginProperty);
+                    set => SetValue(MarginProperty, value);
+                }
+            }
+            """;
+
+        await CSharpAnalyzerTest<UseGeneratedDependencyPropertyOnManualPropertyAnalyzer>.VerifyAnalyzerAsync(source, LanguageVersion.CSharp13);
+    }
+
     // Regression test for a case found in https://github.com/jenius-apps/ambie
     [TestMethod]
     public async Task UseGeneratedDependencyPropertyOnManualPropertyAnalyzer_InvalidRegisterArguments_WCTDP0030_WithInvalidPropertyName_DoesNotWarn()