Update analyzer to use FeatureGuardAttribute

src/tools/illink/src/ILLink.RoslynAnalyzer/DataFlow/FeatureChecksVisitor.cs

@@ -50,7 +50,7 @@ public override FeatureChecksValue VisitPropertyReference (IPropertyReferenceOpe
 			// A single property may serve as a feature check for multiple features.
 			FeatureChecksValue featureChecks = FeatureChecksValue.None;
 			foreach (var analyzer in _dataFlowAnalyzerContext.EnabledRequiresAnalyzers) {
-				if (analyzer.IsFeatureCheck (operation.Property, _dataFlowAnalyzerContext.Compilation)) {
+				if (analyzer.IsFeatureGuard (operation.Property, _dataFlowAnalyzerContext.Compilation)) {
 					var featureCheck = new FeatureChecksValue (analyzer.RequiresAttributeFullyQualifiedName);
 					featureChecks = featureChecks.And (featureCheck);
 				}

src/tools/illink/src/ILLink.RoslynAnalyzer/DataFlow/LocalDataFlowVisitor.cs

@@ -119,7 +119,7 @@ public LocalDataFlowVisitor (
 			var current = state.Current;
 			HandleReturnValue (branchValue, branchValueOperation, in current.Context);
 			// Must be called for every return value even if it did not return an understood condition,
-			// because the non-understood conditions will produce warnings for FeatureCheck properties.
+			// because the non-understood conditions will produce warnings for FeatureGuard properties.
 			HandleReturnConditionValue (conditionValue, branchValueOperation);
 			return null;
 		}

src/tools/illink/src/ILLink.RoslynAnalyzer/DynamicallyAccessedMembersAnalyzer.cs

@@ -21,8 +21,7 @@ public class DynamicallyAccessedMembersAnalyzer : DiagnosticAnalyzer
 		internal const string DynamicallyAccessedMembersAttribute = nameof (DynamicallyAccessedMembersAttribute);
 		public const string attributeArgument = "attributeArgument";
 		public const string FullyQualifiedDynamicallyAccessedMembersAttribute = "System.Diagnostics.CodeAnalysis." + DynamicallyAccessedMembersAttribute;
-		public const string FullyQualifiedFeatureCheckAttribute  = "System.Diagnostics.CodeAnalysis.FeatureCheckAttribute";
-		public const string FullyQualifiedFeatureDependsOnAttribute  = "System.Diagnostics.CodeAnalysis.FeatureDependsOnAttribute";
+		public const string FullyQualifiedFeatureGuardAttribute  = "System.Diagnostics.CodeAnalysis.FeatureGuardAttribute";
 		public static Lazy<ImmutableArray<RequiresAnalyzerBase>> RequiresAnalyzers { get; } = new Lazy<ImmutableArray<RequiresAnalyzerBase>> (GetRequiresAnalyzers);
 		static ImmutableArray<RequiresAnalyzerBase> GetRequiresAnalyzers () =>
 			ImmutableArray.Create<RequiresAnalyzerBase> (
@@ -53,8 +52,8 @@ public static ImmutableArray<DiagnosticDescriptor> GetSupportedDiagnostics ()
 			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.UnrecognizedTypeNameInTypeGetType));
 			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.UnrecognizedParameterInMethodCreateInstance));
 			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.ParametersOfAssemblyCreateInstanceCannotBeAnalyzed));
-			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.ReturnValueDoesNotMatchFeatureChecks));
-			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.InvalidFeatureCheck));
+			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.ReturnValueDoesNotMatchFeatureGuards));
+			diagDescriptorsArrayBuilder.Add (DiagnosticDescriptors.GetDiagnosticDescriptor (DiagnosticId.InvalidFeatureGuard));
 
 			foreach (var requiresAnalyzer in RequiresAnalyzers.Value) {
 				foreach (var diagnosticDescriptor in requiresAnalyzer.SupportedDiagnostics)

src/tools/illink/src/ILLink.RoslynAnalyzer/ISymbolExtensions.cs

@@ -71,26 +71,14 @@ internal static DynamicallyAccessedMemberTypes GetDynamicallyAccessedMemberTypes
 			return (DynamicallyAccessedMemberTypes) dynamicallyAccessedMembers.ConstructorArguments[0].Value!;
 		}
 
-		internal static ValueSet<string> GetFeatureCheckAnnotations (this IPropertySymbol propertySymbol)
+		internal static ValueSet<string> GetFeatureGuardAnnotations (this IPropertySymbol propertySymbol)
 		{
 			HashSet<string> featureSet = new ();
-			foreach (var attributeData in propertySymbol.GetAttributes (DynamicallyAccessedMembersAnalyzer.FullyQualifiedFeatureCheckAttribute)) {
+			foreach (var attributeData in propertySymbol.GetAttributes (DynamicallyAccessedMembersAnalyzer.FullyQualifiedFeatureGuardAttribute)) {
 				if (attributeData.ConstructorArguments is [TypedConstant { Value: INamedTypeSymbol featureType }])
-					AddFeatures (featureType);
+					featureSet.Add (featureType.GetDisplayName ());
 			}
 			return featureSet.Count == 0 ? ValueSet<string>.Empty : new ValueSet<string> (featureSet);
-
-			void AddFeatures (INamedTypeSymbol featureType) {
-				var featureName = featureType.GetDisplayName ();
-				if (!featureSet.Add (featureName))
-					return;
-
-				// Look at FeatureDependsOn attributes on the feature type.
-				foreach (var featureTypeAttributeData in featureType.GetAttributes (DynamicallyAccessedMembersAnalyzer.FullyQualifiedFeatureDependsOnAttribute)) {
-					if (featureTypeAttributeData.ConstructorArguments is [TypedConstant { Value: INamedTypeSymbol featureTypeSymbol }])
-						AddFeatures (featureTypeSymbol);
-				}
-			}
 		}
 
 		internal static bool TryGetReturnAttribute (this IMethodSymbol member, string attributeName, [NotNullWhen (returnValue: true)] out AttributeData? attribute)

src/tools/illink/src/ILLink.RoslynAnalyzer/RequiresAnalyzerBase.cs

@@ -302,19 +302,19 @@ protected virtual bool CreateSpecialIncompatibleMembersDiagnostic (
 		// - custom feature checks defined in library code
 		private protected virtual bool IsRequiresCheck (IPropertySymbol propertySymbol, Compilation compilation) => false;
 
-		internal static bool IsAnnotatedFeatureCheck (IPropertySymbol propertySymbol, string featureName)
+		internal static bool IsAnnotatedFeatureGuard (IPropertySymbol propertySymbol, string featureName)
 		{
-			// Only respect FeatureCheckAttribute on static boolean properties.
+			// Only respect FeatureGuardAttribute on static boolean properties.
 			if (!propertySymbol.IsStatic || propertySymbol.Type.SpecialType != SpecialType.System_Boolean)
 				return false;
 
-			ValueSet<string> featureCheckAnnotations = propertySymbol.GetFeatureCheckAnnotations ();
+			ValueSet<string> featureCheckAnnotations = propertySymbol.GetFeatureGuardAnnotations ();
 			return featureCheckAnnotations.Contains (featureName);
 		}
 
-		internal bool IsFeatureCheck (IPropertySymbol propertySymbol, Compilation compilation)
+		internal bool IsFeatureGuard (IPropertySymbol propertySymbol, Compilation compilation)
 		{
-			return IsAnnotatedFeatureCheck (propertySymbol, RequiresAttributeFullyQualifiedName)
+			return IsAnnotatedFeatureGuard (propertySymbol, RequiresAttributeFullyQualifiedName)
 				|| IsRequiresCheck (propertySymbol, compilation);
 		}
 

src/tools/illink/src/ILLink.RoslynAnalyzer/TrimAnalysis/FeatureCheckReturnValuePattern.cs

@@ -39,7 +39,7 @@ public IEnumerable<Diagnostic> CollectDiagnostics (DataFlowAnalyzerContext conte
 			if (!OwningSymbol.IsStatic || OwningSymbol.Type.SpecialType != SpecialType.System_Boolean) {
 				// Warn about invalid feature checks (non-static or non-bool properties)
 				diagnosticContext.AddDiagnostic (
-					DiagnosticId.InvalidFeatureCheck);
+					DiagnosticId.InvalidFeatureGuard);
 				return diagnosticContext.Diagnostics;
 			}
 
@@ -57,7 +57,7 @@ public IEnumerable<Diagnostic> CollectDiagnostics (DataFlowAnalyzerContext conte
 
 					if (!returnValueFeatures.Contains (feature)) {
 						diagnosticContext.AddDiagnostic (
-							DiagnosticId.ReturnValueDoesNotMatchFeatureChecks,
+							DiagnosticId.ReturnValueDoesNotMatchFeatureGuards,
 							OwningSymbol.GetDisplayName (),
 							feature);
 					}

src/tools/illink/src/ILLink.RoslynAnalyzer/TrimAnalysis/TrimAnalysisVisitor.cs

@@ -436,12 +436,12 @@ public override void HandleReturnConditionValue (FeatureChecksValue returnCondit
 			if (OwningSymbol is not IMethodSymbol method)
 				return;
 
-			// FeatureCheck validation needs to happen only for properties.
+			// FeatureGuard validation needs to happen only for properties.
 			if (method.MethodKind != MethodKind.PropertyGet)
 				return;
 
 			IPropertySymbol propertySymbol = (IPropertySymbol) method.AssociatedSymbol!;
-			var featureCheckAnnotations = propertySymbol.GetFeatureCheckAnnotations ();
+			var featureCheckAnnotations = propertySymbol.GetFeatureGuardAnnotations ();
 
 			// If there are no feature checks, there is nothing to validate.
 			if (featureCheckAnnotations.IsEmpty())

src/tools/illink/src/ILLink.Shared/DiagnosticId.cs

@@ -204,8 +204,8 @@ public enum DiagnosticId
 		RequiresDynamicCodeOnStaticConstructor = 3056,
 
 		// Feature guard diagnostic ids.
-		ReturnValueDoesNotMatchFeatureChecks = 4000,
-		InvalidFeatureCheck = 4001
+		ReturnValueDoesNotMatchFeatureGuards = 4000,
+		InvalidFeatureGuard = 4001
 	}
 
 	public static class DiagnosticIdExtensions

src/tools/illink/src/ILLink.Shared/SharedStrings.resx

@@ -1197,16 +1197,16 @@
   <data name="RedundantSuppressionTitle" xml:space="preserve">
     <value>Unused 'UnconditionalSuppressMessageAttribute' found. Consider removing the unused warning suppression.</value>
   </data>
-  <data name="ReturnValueDoesNotMatchFeatureChecksMessage" xml:space="preserve">
-    <value>Return value does not match FeatureCheckAttribute '{1}'.</value>
+  <data name="ReturnValueDoesNotMatchFeatureGuardsMessage" xml:space="preserve">
+    <value>Return value does not match FeatureGuardAttribute '{1}'.</value>
   </data>
-  <data name="ReturnValueDoesNotMatchFeatureChecksTitle" xml:space="preserve">
-    <value>Return value does not match FeatureCheck annotations of the property. The check should return false whenever any of the features referenced in the FeatureCheck annotations is disabled.</value>
+  <data name="ReturnValueDoesNotMatchFeatureGuardsTitle" xml:space="preserve">
+    <value>Return value does not match FeatureGuard annotations of the property. The check should return false whenever any of the features referenced in the FeatureGuard annotations is disabled.</value>
   </data>
-  <data name="InvalidFeatureCheckMessage" xml:space="preserve">
-    <value>Invalid FeatureCheckAttribute. The attribute must be placed on a static boolean property with only a 'get' accessor.</value>
+  <data name="InvalidFeatureGuardMessage" xml:space="preserve">
+    <value>Invalid FeatureGuardAttribute. The attribute must be placed on a static boolean property with only a 'get' accessor.</value>
   </data>
-  <data name="InvalidFeatureCheckTitle" xml:space="preserve">
-    <value>Invalid FeatureCheckAttribute.</value>
+  <data name="InvalidFeatureGuardTitle" xml:space="preserve">
+    <value>Invalid FeatureGuardAttribute.</value>
   </data>
 </root>

src/tools/illink/test/ILLink.RoslynAnalyzer.Tests/DataFlowTests.cs

@@ -150,7 +150,7 @@ public Task FeatureCheckDataFlow ()
 		}
 
 		[Fact]
-		public Task FeatureCheckAttributeDataFlow ()
+		public Task FeatureGuardAttributeDataFlow ()
 		{
 			return RunTest ();
 		}

src/tools/illink/test/Mono.Linker.Tests.Cases.Expectations/Support/FeatureCheckAttribute.cs → src/tools/illink/test/Mono.Linker.Tests.Cases.Expectations/Support/FeatureGuardAttribute.cs

@@ -3,13 +3,13 @@
 
 namespace System.Diagnostics.CodeAnalysis
 {
-    // Allow AttributeTargets.Method for testing invalid usages of a custom FeatureCheckAttribute
-    [AttributeUsage (AttributeTargets.Property | AttributeTargets.Method, Inherited=false)]
-    public sealed class FeatureCheckAttribute : Attribute
+    // Allow AttributeTargets.Method for testing invalid usages of a custom FeatureGuardAttribute
+    [AttributeUsage (AttributeTargets.Property | AttributeTargets.Method, Inherited = false, AllowMultiple = true)]
+    public sealed class FeatureGuardAttribute : Attribute
     {
         public Type FeatureType { get; }
 
-        public FeatureCheckAttribute (Type featureType)
+        public FeatureGuardAttribute (Type featureType)
         {
             FeatureType = featureType;
         }