[generator] Fix availability in property accessor when different from the property itself.

Scenario:

* Type is available on iOS, tvOS.
* Property in the type is available on iOS (and not tvOS).
* Property accessor has explicit availability attributes for iOS.

Then the property accessor would get the availability attribute for tvOS from the
type, and not the (un)availability attribute from the property.

The fix is to make sure the parent context is the property (and not the type) when
processing availability attributes for the accessor.

Author: rolfbjarne

src/generator.cs

@@ -3677,15 +3677,16 @@ List<AvailabilityBaseAttribute> GetAllParentAttributes (MemberInfo context)
 		}
 	}
 
-	AvailabilityBaseAttribute [] GetPlatformAttributesToPrint (MemberInfo mi, Type type, MemberInfo inlinedType)
+	AvailabilityBaseAttribute [] GetPlatformAttributesToPrint (MemberInfo mi, MemberInfo context, MemberInfo inlinedType)
 	{
 		// Attributes are directly on the member
 		List<AvailabilityBaseAttribute> memberAvailability = AttributeManager.GetCustomAttributes<AvailabilityBaseAttribute> (mi).ToList ();
 
 		// Due to differences between Xamarin and NET6 availability attributes, we have to synthesize many duplicates for NET6
 		// See https://github.com/xamarin/xamarin-macios/issues/10170 for details
 #if NET
-		MemberInfo context = type ?? FindContainingContext (mi);
+		if (context is null)
+			context = FindContainingContext (mi);
 		// Attributes on the _target_ context, the class itself or the target of the protocol inlining
 		List<AvailabilityBaseAttribute> parentContextAvailability = GetAllParentAttributes (context);
 		// (Optional) Attributes from the inlined protocol type itself
@@ -3769,7 +3770,7 @@ public bool PrintPlatformAttributes (MemberInfo mi, Type inlinedType = null)
 
 		AvailabilityBaseAttribute [] type_ca = null;
 
-		foreach (var availability in GetPlatformAttributesToPrint (mi, mi.DeclaringType, inlinedType)) {
+		foreach (var availability in GetPlatformAttributesToPrint (mi, null, inlinedType)) {
 			var t = inlinedType ?? (mi as TypeInfo) ?? mi.DeclaringType;
 			if (type_ca == null) {
 				if (t != null)

tests/generator/BGenTests.cs

@@ -1155,6 +1155,35 @@ public void GeneratedAttributeOnPropertyAccessors ()
 			Assert.AreEqual (string.Empty, RenderSupportedOSPlatformAttributes (getter), "Getter Attributes");
 		}
 
+#if !NET
+		[Ignore ("This test only applies to .NET")]
+#endif
+		[Test]
+		public void GeneratedAttributeOnPropertyAccessors2 ()
+		{
+			var bgen = BuildFile (Profile.MacCatalyst, "tests/generated-attribute-on-property-accessors2.cs");
+
+			var messaging = bgen.ApiAssembly.MainModule.Types.First (v => v.Name == "ISomething");
+			var property = messaging.Properties.First (v => v.Name == "MicrophoneEnabled");
+			var getter = messaging.Methods.First (v => v.Name == "get_MicrophoneEnabled");
+			var setter = messaging.Methods.First (v => v.Name == "set_MicrophoneEnabled");
+
+			var expectedPropertyAttributes =
+@"[SupportedOSPlatform(""ios"")]
+[SupportedOSPlatform(""maccatalyst"")]
+[SupportedOSPlatform(""macos11.0"")]
+[UnsupportedOSPlatform(""tvos"")]";
+			var expectedSetterAttributes =
+@"[SupportedOSPlatform(""ios"")]
+[SupportedOSPlatform(""maccatalyst"")]
+[SupportedOSPlatform(""macos11.0"")]
+[UnsupportedOSPlatform(""tvos"")]";
+
+			Assert.AreEqual (expectedPropertyAttributes, RenderSupportedOSPlatformAttributes (property), "Property attributes");
+			Assert.AreEqual (string.Empty, RenderSupportedOSPlatformAttributes (getter), "Getter Attributes");
+			Assert.AreEqual (expectedSetterAttributes, RenderSupportedOSPlatformAttributes (setter), "Setter Attributes");
+		}
+
 		BGenTool BuildFile (Profile profile, params string [] filenames)
 		{
 			return BuildFile (profile, true, false, filenames);

tests/generator/tests/generated-attribute-on-property-accessors2.cs

@@ -0,0 +1,25 @@
+using System;
+using Foundation;
+using ObjCRuntime;
+
+namespace NS {
+	[Introduced (PlatformName.iOS, 9, 0)]
+	[Introduced (PlatformName.TvOS, 10, 0)]
+	[Introduced (PlatformName.MacOSX, 11, 0)]
+	[Introduced (PlatformName.MacCatalyst, 13, 1)]
+	[BaseType (typeof (NSObject))]
+	[DisableDefaultCtor]
+	[Sealed]
+	interface ISomething {
+		[NoTV]
+		[Introduced (PlatformName.MacCatalyst, 13, 1)]
+		[Export ("microphoneEnabled", ArgumentSemantic.Assign)]
+		bool MicrophoneEnabled {
+			[Bind ("isMicrophoneEnabled")]
+			get;
+			[Introduced (PlatformName.iOS, 10, 0)]
+			[Introduced (PlatformName.MacCatalyst, 13, 1)]
+			set;
+		}
+	}
+}