Closes #451 - Add pragma restore directive for the CS0108 warning

src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/Models/PropertyInfo.cs

@@ -20,6 +20,7 @@ namespace CommunityToolkit.Mvvm.SourceGenerators.ComponentModel.Models;
 /// <param name="IsOldPropertyValueDirectlyReferenced">Whether the old property value is being directly referenced.</param>
 /// <param name="IsReferenceTypeOrUnconstraindTypeParameter">Indicates whether the property is of a reference type or an unconstrained type parameter.</param>
 /// <param name="IncludeMemberNotNullOnSetAccessor">Indicates whether to include nullability annotations on the setter.</param>
+/// <param name="hidesInheritedProperty">Indicates whether the generated property should hide an inherited property declaration.</param>
 /// <param name="ForwardedAttributes">The sequence of forwarded attributes for the generated property.</param>
 internal sealed record PropertyInfo(
     string TypeNameWithNullabilityAnnotations,
@@ -33,4 +34,5 @@ internal sealed record PropertyInfo(
     bool IsOldPropertyValueDirectlyReferenced,
     bool IsReferenceTypeOrUnconstraindTypeParameter,
     bool IncludeMemberNotNullOnSetAccessor,
+    bool hidesInheritedProperty,
     EquatableArray<AttributeInfo> ForwardedAttributes);

src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.Execute.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.ComponentModel;
@@ -118,6 +119,7 @@ public static bool TryGetInfo(
             bool hasOrInheritsClassLevelNotifyPropertyChangedRecipients = false;
             bool hasOrInheritsClassLevelNotifyDataErrorInfo = false;
             bool hasAnyValidationAttributes = false;
+            bool hidesInheritedProperty = false;
             bool isOldPropertyValueDirectlyReferenced = IsOldPropertyValueDirectlyReferenced(fieldSymbol, propertyName);
 
             token.ThrowIfCancellationRequested();
@@ -194,6 +196,15 @@ public static bool TryGetInfo(
                     forwardedAttributes.Add(AttributeInfo.Create(attributeData));
                 }
 
+                // Check if the generated property should hide an inherited property declaration
+                if (attributeData.AttributeClass?.HasFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservablePropertyAttribute") == true)
+                {
+                    if (Convert.ToBoolean(attributeData.ConstructorArguments[0].Value) == true)
+                    {
+                        hidesInheritedProperty = true;
+                    }
+                }
+
                 // Also track the current attribute for forwarding if it is of any of the following types:
                 //   - Display attributes (System.ComponentModel.DataAnnotations.DisplayAttribute)
                 //   - UI hint attributes(System.ComponentModel.DataAnnotations.UIHintAttribute)
@@ -308,6 +319,7 @@ public static bool TryGetInfo(
                 isOldPropertyValueDirectlyReferenced,
                 isReferenceTypeOrUnconstraindTypeParameter,
                 includeMemberNotNullOnSetAccessor,
+                hidesInheritedProperty,
                 forwardedAttributes.ToImmutable());
 
             diagnostics = builder.ToImmutable();
@@ -1016,11 +1028,18 @@ public static MemberDeclarationSyntax GetPropertySyntax(PropertyInfo propertyInf
             // [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
             // [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             // <FORWARDED_ATTRIBUTES>
-            // public <FIELD_TYPE><NULLABLE_ANNOTATION?> <PROPERTY_NAME>
+            // public <NEW_KEYWORD> <FIELD_TYPE><NULLABLE_ANNOTATION?> <PROPERTY_NAME>
             // {
             //     get => <FIELD_NAME>;
             //     <SET_ACCESSOR>
             // }
+
+            List<SyntaxToken> propertyDeclarationModifier = new() { Token(SyntaxKind.PublicKeyword) };
+            if (propertyInfo.hidesInheritedProperty)
+            {
+                propertyDeclarationModifier.Add(Token(SyntaxKind.NewKeyword));
+            }
+
             return
                 PropertyDeclaration(propertyType, Identifier(propertyInfo.PropertyName))
                 .AddAttributeLists(
@@ -1032,7 +1051,7 @@ public static MemberDeclarationSyntax GetPropertySyntax(PropertyInfo propertyInf
                     .WithOpenBracketToken(Token(TriviaList(Comment($"/// <inheritdoc cref=\"{getterFieldIdentifierName}\"/>")), SyntaxKind.OpenBracketToken, TriviaList())),
                     AttributeList(SingletonSeparatedList(Attribute(IdentifierName("global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage")))))
                 .AddAttributeLists(forwardedAttributes.ToArray())
-                .AddModifiers(Token(SyntaxKind.PublicKeyword))
+                .AddModifiers(propertyDeclarationModifier.ToArray())
                 .AddAccessorListAccessors(
                     AccessorDeclaration(SyntaxKind.GetAccessorDeclaration)
                     .WithExpressionBody(ArrowExpressionClause(getterFieldExpression))

src/CommunityToolkit.Mvvm.SourceGenerators/Models/HierarchyInfo.Syntax.cs

@@ -60,10 +60,17 @@ public CompilationUnitSyntax GetCompilationUnit(
         //
         // <auto-generated/>
         // #pragma warning disable
+        // #pragma warning restore CS0108 // Member hides inherited member; missing new keyword
+        //
         // #nullable enable
+
+        SeparatedSyntaxList<ExpressionSyntax> pragmaWarningCodesToPreserve = new SeparatedSyntaxList<ExpressionSyntax>()
+            .Add(IdentifierName(Identifier(default, SyntaxKind.IdentifierName, "CS0108", "CS0108", TriviaList(Comment("// Member hides inherited member; missing new keyword")))));
+
         SyntaxTriviaList syntaxTriviaList = TriviaList(
             Comment("// <auto-generated/>"),
             Trivia(PragmaWarningDirectiveTrivia(Token(SyntaxKind.DisableKeyword), true)),
+            Trivia(PragmaWarningDirectiveTrivia(Token(SyntaxKind.RestoreKeyword), pragmaWarningCodesToPreserve, true)),
             Trivia(NullableDirectiveTrivia(Token(SyntaxKind.EnableKeyword), true)));
 
         if (Namespace is "")

src/CommunityToolkit.Mvvm/ComponentModel/Attributes/ObservablePropertyAttribute.cs

@@ -54,4 +54,19 @@ namespace CommunityToolkit.Mvvm.ComponentModel;
 [AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
 public sealed class ObservablePropertyAttribute : Attribute
 {
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ObservablePropertyAttribute"/> class. 
+    /// </summary>
+    /// <param name="hidesInheritedProperty">
+    /// Specifies if the generated property will hide an inherited property declaration.
+    /// </param>
+    public ObservablePropertyAttribute(bool hidesInheritedProperty = false)
+    {
+        Hidesinheritedproperty = hidesInheritedProperty;
+    }
+
+    /// <summary>
+    /// Specifies if the generated property will hide an inherited property declaration.
+    /// </summary>
+    public bool Hidesinheritedproperty { get; }
 }