[Mono.Android] Fix build warnings in hand-written code

src/Mono.Android/Android.Animation/AnimatorSet.cs

@@ -6,7 +6,7 @@ namespace Android.Animation
 {
 	public partial class AnimatorSet
 	{
-		static Delegate cb_setDuration_SetDuration_J_Landroid_animation_Animator_;
+		static Delegate? cb_setDuration_SetDuration_J_Landroid_animation_Animator_;
 
 		[Register ("setDuration", "(J)Landroid/animation/Animator;", "GetSetDuration_JHandler")]
 		public override unsafe Android.Animation.Animator SetDuration (long duration)
@@ -16,7 +16,8 @@ public override unsafe Android.Animation.Animator SetDuration (long duration)
 				JniArgumentValue* __args = stackalloc JniArgumentValue [1];
 				__args [0] = new JniArgumentValue (duration);
 				var __rm = _members.InstanceMethods.InvokeVirtualObjectMethod (__id, this, __args);
-				return global::Java.Lang.Object.GetObject<Android.Animation.Animator> (__rm.Handle, JniHandleOwnership.TransferLocalRef);
+				var __ret = global::Java.Lang.Object.GetObject<Android.Animation.Animator> (__rm.Handle, JniHandleOwnership.TransferLocalRef);
+				return __ret ?? throw new InvalidOperationException ("Unable to marshal the return value to a managed Android.Animation.Animator instance.");
 			} finally {
 			}
 		}
@@ -35,6 +36,8 @@ static IntPtr n_SetDuration_J (IntPtr jnienv, IntPtr native__this, long duration
 
 			try {
 				var __this = global::Java.Lang.Object.GetObject<Android.Animation.AnimatorSet> (jnienv, native__this, JniHandleOwnership.DoNotTransfer);
+				if (__this is null)
+					throw new InvalidOperationException ("Unable to marshal the native handle to a managed Android.Animation.AnimatorSet instance.");
 				return JNIEnv.ToLocalJniHandle (__this.SetDuration (duration));
 			} catch (global::System.Exception __e) {
 				__r.OnUserUnhandledException (ref __envp, __e);

src/Mono.Android/Android.Animation/ValueAnimator.cs

@@ -6,7 +6,7 @@ namespace Android.Animation
 {
 	public partial class ValueAnimator
 	{
-		static Delegate cb_setDuration_SetDuration_J_Landroid_animation_Animator_;
+		static Delegate? cb_setDuration_SetDuration_J_Landroid_animation_Animator_;
 
 		[Register ("setDuration", "(J)Landroid/animation/Animator;", "GetSetDuration_JHandler")]
 		public override unsafe Android.Animation.Animator SetDuration (long duration)
@@ -16,7 +16,8 @@ public override unsafe Android.Animation.Animator SetDuration (long duration)
 				JniArgumentValue* __args = stackalloc JniArgumentValue [1];
 				__args [0] = new JniArgumentValue (duration);
 				var __rm = _members.InstanceMethods.InvokeVirtualObjectMethod (__id, this, __args);
-				return global::Java.Lang.Object.GetObject<Android.Animation.Animator> (__rm.Handle, JniHandleOwnership.TransferLocalRef);
+				var __ret = global::Java.Lang.Object.GetObject<Android.Animation.Animator> (__rm.Handle, JniHandleOwnership.TransferLocalRef);
+				return __ret ?? throw new InvalidOperationException ("Unable to marshal the return value to a managed Android.Animation.Animator instance.");
 			} finally {
 			}
 		}
@@ -35,6 +36,8 @@ static IntPtr n_SetDuration_J (IntPtr jnienv, IntPtr native__this, long duration
 
 			try {
 				var __this = global::Java.Lang.Object.GetObject<Android.Animation.ValueAnimator> (jnienv, native__this, JniHandleOwnership.DoNotTransfer);
+				if (__this is null)
+					throw new InvalidOperationException ("Unable to marshal the native handle to a managed Android.Animation.ValueAnimator instance.");
 				return JNIEnv.ToLocalJniHandle (__this.SetDuration (duration));
 			} catch (global::System.Exception __e) {
 				__r.OnUserUnhandledException (ref __envp, __e);

src/Mono.Android/Android.App/AlertDialog.cs

@@ -17,14 +17,14 @@ public partial class Builder {
 
 			public event EventHandler<Android.Widget.AdapterView.ItemSelectedEventArgs> ItemSelected {
 				add {
-					AndroidEventHelper.AddEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
+					EventHelper.AddEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
 							ref weak_implementor_SetOnItemSelectedListener,
 							CreateItemSelectedImplementor,
 							__SetOnItemSelectedListener,
 							__h => __h.OnItemSelectedHandler += value);
 				}
 				remove {
-					AndroidEventHelper.RemoveEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
+					EventHelper.RemoveEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
 							ref weak_implementor_SetOnItemSelectedListener,
 							AdapterView.IOnItemSelectedListenerImplementor.__IsEmpty,
 							__SetOnItemSelectedListener,
@@ -34,14 +34,14 @@ public event EventHandler<Android.Widget.AdapterView.ItemSelectedEventArgs> Item
 
 			public event EventHandler<Android.Widget.AdapterView.NothingSelectedEventArgs> NothingSelected {
 				add {
-					AndroidEventHelper.AddEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
+					EventHelper.AddEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
 							ref weak_implementor_SetOnItemSelectedListener,
 							CreateItemSelectedImplementor,
 							__SetOnItemSelectedListener,
 							__h => __h.OnNothingSelectedHandler += value);
 				}
 				remove {
-					AndroidEventHelper.RemoveEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
+					EventHelper.RemoveEventHandler<AdapterView.IOnItemSelectedListener, AdapterView.IOnItemSelectedListenerImplementor>(
 							ref weak_implementor_SetOnItemSelectedListener,
 							AdapterView.IOnItemSelectedListenerImplementor.__IsEmpty,
 							__SetOnItemSelectedListener,

src/Mono.Android/Android.App/SyncContext.cs

@@ -25,7 +25,7 @@ static bool EnsureLooper ([NotNullWhen (true)]Looper? looper, SendOrPostCallback
 			return true;
 		}
 
-		public override void Post (SendOrPostCallback d, object state)
+		public override void Post (SendOrPostCallback d, object? state)
 		{
 			var looper = Application.Context?.MainLooper;
 			if (!EnsureLooper (looper, d))
@@ -35,7 +35,7 @@ public override void Post (SendOrPostCallback d, object state)
 			}
 		}
 
-		public override void Send (SendOrPostCallback d, object state)
+		public override void Send (SendOrPostCallback d, object? state)
 		{
 			var looper = Looper.MainLooper;
 			if (!EnsureLooper (looper, d))

src/Mono.Android/Android.Bluetooth/BluetoothDevice.cs

@@ -6,11 +6,13 @@ public sealed partial class BluetoothDevice
 	{
 		// These methods were obsoleted as a warning in API-31
 		[global::System.Obsolete ("This method has the wrong enumeration. Use the version that takes an 'Android.Bluetooth.BluetoothPhy' instead.")]
+		[global::System.Runtime.Versioning.ObsoletedOSPlatformAttribute ("android37.0")]
 		[global::System.Runtime.Versioning.SupportedOSPlatformAttribute ("android26.0")]
 		public unsafe Android.Bluetooth.BluetoothGatt? ConnectGatt (Android.Content.Context? context, bool autoConnect, Android.Bluetooth.BluetoothGattCallback? @callback, [global::Android.Runtime.GeneratedEnum] Android.Bluetooth.BluetoothTransports transport, [global::Android.Runtime.GeneratedEnum] Android.Bluetooth.LE.ScanSettingsPhy phy)
 			=> ConnectGatt (context, autoConnect, @callback, transport, (Android.Bluetooth.BluetoothPhy) phy);
 
 		[global::System.Obsolete ("This method has the wrong enumeration. Use the version that takes an 'Android.Bluetooth.BluetoothPhy' instead.")]
+		[global::System.Runtime.Versioning.ObsoletedOSPlatformAttribute ("android37.0")]
 		[global::System.Runtime.Versioning.SupportedOSPlatformAttribute ("android26.0")]
 		public unsafe Android.Bluetooth.BluetoothGatt? ConnectGatt (Android.Content.Context? context, bool autoConnect, Android.Bluetooth.BluetoothGattCallback? @callback, [global::Android.Runtime.GeneratedEnum] Android.Bluetooth.BluetoothTransports transport, [global::Android.Runtime.GeneratedEnum] Android.Bluetooth.LE.ScanSettingsPhy phy, Android.OS.Handler? handler)
 			=> ConnectGatt (context, autoConnect, @callback, transport, (Android.Bluetooth.BluetoothPhy) phy, handler);

src/Mono.Android/Android.Content.Res/IXmlResourceParser.cs

@@ -9,13 +9,13 @@ public partial interface IXmlResourceParser : Android.Util.IAttributeSet, IXmlPu
 	{
 		#region These members are dare defined here to avoid conflicts between IAttributeSet and IXmlPullParser.
 
-		int AttributeCount { get; }
+		new int AttributeCount { get; }
 
-		string PositionDescription { get; }
+		new string PositionDescription { get; }
 
-		string GetAttributeName (int pos);
-		string GetAttributeValue (int pos);
-		string? GetAttributeValue (string? ns, string? name);
+		new string GetAttributeName (int pos);
+		new string GetAttributeValue (int pos);
+		new string? GetAttributeValue (string? ns, string? name);
 		#endregion
 	}
 }

src/Mono.Android/Android.Graphics/AndroidBitmapInfo.cs

@@ -58,7 +58,7 @@ public override int GetHashCode ()
 		}
 
 		/// <inheritdoc />
-		public override bool Equals (object value)
+		public override bool Equals (object? value)
 		{
 			if (!(value is AndroidBitmapInfo))
 				return false;

src/Mono.Android/Android.Graphics/Color.cs

@@ -87,7 +87,7 @@ public override string ToString ()
 			return FormattableString.Invariant ($"Color [A={A}, R={R}, G={G}, B={B}]");
 		}
 
-		public override bool Equals (object obj)
+		public override bool Equals (object? obj)
 		{
 			if (!(obj is Color))
 				return false;
@@ -440,7 +440,7 @@ public override Type MarshalType {
 			get { return typeof (int); }
 		}
 
-		public override Color CreateGenericValue (ref JniObjectReference reference, JniObjectReferenceOptions options, Type targetType)
+		public override Color CreateGenericValue (ref JniObjectReference reference, JniObjectReferenceOptions options, Type? targetType)
 		{
 			throw new NotImplementedException ();
 		}
@@ -457,7 +457,7 @@ public override void DestroyGenericArgumentState (Color value, ref JniValueMarsh
 
 		[RequiresDynamicCode (ExpressionRequiresUnreferencedCode)]
 		[RequiresUnreferencedCode (ExpressionRequiresUnreferencedCode)]
-		public override Expression CreateParameterToManagedExpression (JniValueMarshalerContext context, ParameterExpression sourceValue, ParameterAttributes synchronize, Type targetType)
+		public override Expression CreateParameterToManagedExpression (JniValueMarshalerContext context, ParameterExpression sourceValue, ParameterAttributes synchronize, Type? targetType)
 		{
 			var c = typeof (Color).GetConstructor (new[]{typeof (int)})!;
 			var v = Expression.Variable (typeof (Color), sourceValue.Name + "_val");

src/Mono.Android/Android.OS/AsyncTask.cs

@@ -19,7 +19,7 @@ public abstract class AsyncTask<
 	> : AsyncTask {
 
 		static IntPtr java_class_handle;
-		internal static IntPtr class_ref {
+		internal static new IntPtr class_ref {
 			get {
 				return JNIEnv.FindClass ("android/os/AsyncTask", ref java_class_handle);
 			}

src/Mono.Android/Android.Runtime/InputStreamAdapter.cs

@@ -28,13 +28,15 @@ public override int Read ()
 			return BaseStream.ReadByte ();
 		}
 
-		public override int Read (byte[] bytes)
+		public override int Read (byte[]? bytes)
 		{
+			ArgumentNullException.ThrowIfNull (bytes);
 			return Read (bytes, 0, bytes.Length);
 		}
 
-		public override int Read (byte[] bytes, int offset, int length)
+		public override int Read (byte[]? bytes, int offset, int length)
 		{
+			ArgumentNullException.ThrowIfNull (bytes);
 			int res = BaseStream.Read (bytes, offset, length);
 			if (res == 0)
 				return -1;

src/Mono.Android/Android.Runtime/JNIEnv.cs

@@ -26,14 +26,11 @@ public static partial class JNIEnv {
 
 		static Array ArrayCreateInstance (Type elementType, int length)
 		{
-			if (RuntimeFeature.TrimmableTypeMap) {
-				if (RuntimeFeature.IsCoreClrRuntime) {
-					// CoreCLR runtime type loader can construct any T[] dynamically.
-					// IsDynamicCodeSupported is a [FeatureGuard] so this branch is
-					// dead-coded under PublishAot.
-					return Array.CreateInstance (elementType, length);
-				}
+			if (System.Runtime.CompilerServices.RuntimeFeature.IsDynamicCodeSupported) {
+				return Array.CreateInstance (elementType, length);
+			}
 
+			if (RuntimeFeature.TrimmableTypeMap) {
 				if (RuntimeFeature.IsNativeAotRuntime) {
 					// NativeAOT: resolve via per-rank typemap + generated array proxy.
 					if (TrimmableTypeMap.Instance.TryGetArrayProxy (elementType, additionalRank: 1, out var arrayProxy)) {
@@ -47,9 +44,18 @@ static Array ArrayCreateInstance (Type elementType, int length)
 					$"ensure the mapping is emitted for that rank (for example by increasing _AndroidTrimmableTypeMapMaxArrayRank) or report an issue.");
 			}
 
-			#pragma warning disable IL3050 // legacy fallback path
-			return Array.CreateInstance (elementType, length);
-			#pragma warning restore IL3050
+			if (RuntimeFeature.ManagedTypeMap) {
+				return ArrayCreateInstanceWithSuppression (elementType, length);
+
+				[UnconditionalSuppressMessage ("Trimming", "IL3050:RequiresDynamicCode",
+					Justification = "Temporarily suppressed for the \"ManagedTypeMap\".")]
+				Array ArrayCreateInstanceWithSuppression (Type elementType, int length)
+				{
+					return Array.CreateInstance (elementType, length);
+				}
+			}
+
+			throw new NotSupportedException ($"It is not possible to create an array with element type '{elementType}'.");
 		}
 
 		static int GetArrayRank (Type elementType)
@@ -433,7 +439,7 @@ public static unsafe IntPtr NewObject (IntPtr jclass, IntPtr jmethod, params JVa
 				return NewObject (jclass, jmethod, p);
 		}
 
-		public static string GetClassNameFromInstance (IntPtr jobject)
+		public static string? GetClassNameFromInstance (IntPtr jobject)
 		{
 			return JniEnvironment.Types.GetJniTypeNameFromInstance (new JniObjectReference (jobject));
 		}
@@ -486,6 +492,8 @@ static unsafe IntPtr monovm_typemap_managed_to_java (Type type, byte* mvidptr)
 				if (RuntimeFeature.IsMonoRuntime) {
 					ret = monovm_typemap_managed_to_java (type, mvidptr);
 				} else if (RuntimeFeature.IsCoreClrRuntime) {
+					if (type.FullName is null)
+						return null;
 					ret = RuntimeNativeMethods.clr_typemap_managed_to_java (type.FullName, (IntPtr)mvidptr);
 				} else {
 					throw new NotSupportedException ("Internal error: unknown runtime not supported");
@@ -695,7 +703,7 @@ public static void CopyArray (IntPtr src, string[] dest)
 					// FIXME: Since a Dictionary<Type, Func> is used here, the trimmer will not be able to properly analyze `Type t`
 					// error IL2111: Method 'lambda expression' with parameters or return value with `DynamicallyAccessedMembersAttribute` is accessed via reflection. Trimmer can't guarantee availability of the requirements of the method.
 					[UnconditionalSuppressMessage ("Trimming", "IL2067", Justification = "FIXME: https://github.com/xamarin/xamarin-android/issues/8724")]
-					static object? GetObject (IntPtr e, Type t) =>
+					static object? GetObject (IntPtr e, Type? t) =>
 						Java.Lang.Object.GetObject (e, JniHandleOwnership.TransferLocalRef, t);
 				} },
 				{ typeof (Array), (type, source, index) => {
@@ -717,7 +725,7 @@ static TValue GetConverter<TValue>(Dictionary<Type, TValue> dict, Type? elementT
 			}
 
 			if (array != IntPtr.Zero) {
-				string type = GetClassNameFromInstance (array);
+				string? type = GetClassNameFromInstance (array);
 				if (type == null || type.Length < 1 || type [0] != '[')
 					throw new InvalidOperationException ("Unsupported java array type: " + type);
 

src/Mono.Android/Android.Runtime/JavaCollection.cs

@@ -389,12 +389,12 @@ System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator ()
 			return GetEnumerator ()!;
 		}
 
-		public IEnumerator<T?> GetEnumerator ()
+		public new IEnumerator<T?> GetEnumerator ()
 		{
 			return System.Linq.Extensions.ToEnumerator_Dispose<T> (Iterator());
 		}
 
-		public static ICollection<T>? FromJniHandle (IntPtr handle, JniHandleOwnership transfer)
+		public new static ICollection<T>? FromJniHandle (IntPtr handle, JniHandleOwnership transfer)
 		{
 			if (handle == IntPtr.Zero)
 				return null;

src/Mono.Android/Android.Runtime/JavaDictionary.cs

@@ -518,11 +518,11 @@ public V this [K key] {
 			}
 		}
 
-		public ICollection<K> Keys {
+		public new ICollection<K> Keys {
 			get { return new JavaSet<K> (GetKeys (), JniHandleOwnership.TransferLocalRef); }
 		}
 
-		public ICollection<V> Values {
+		public new ICollection<V> Values {
 			get { return new JavaCollection<V> (GetValues (), JniHandleOwnership.TransferLocalRef); }
 		}
 
@@ -588,7 +588,7 @@ IEnumerator IEnumerable.GetEnumerator ()
 			return GetEnumerator ();
 		}
 
-		public IEnumerator<KeyValuePair<K, V>> GetEnumerator ()
+		public new IEnumerator<KeyValuePair<K, V>> GetEnumerator ()
 		{
 			foreach (K key in Keys)
 #pragma warning disable CS8604 // Possible null reference argument.
@@ -640,7 +640,7 @@ public bool TryGetValue (K key, out V value)
 			return ContainsKey (key);
 		}
 
-		public static IDictionary<K, V>? FromJniHandle (IntPtr handle, JniHandleOwnership transfer)
+		public new static IDictionary<K, V>? FromJniHandle (IntPtr handle, JniHandleOwnership transfer)
 		{
 			if (handle == IntPtr.Zero)
 				return null;

src/Mono.Android/Android.Runtime/JavaList.cs

@@ -585,7 +585,7 @@ public virtual bool ContainsAll (JavaList collection)
 			return true;
 		}
 
-		public virtual bool Equals (Java.Lang.Object obj)
+		public virtual new bool Equals (Java.Lang.Object obj)
 		{
 			var collection = obj as JavaList;
 			if (collection == null || Count != collection.Count)
@@ -785,7 +785,7 @@ internal unsafe void InternalSet (int location, T value)
 
 		// C#'s IList<T> allows nulls but is not annotated as MaybeNull.
 		[MaybeNull]
-		public T this [int index] {
+		public new T this [int index] {
 			[return: MaybeNull]
 #pragma warning disable CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member because of nullability attributes.
 			get {
@@ -879,7 +879,7 @@ System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator ()
 			return GetEnumerator ()!;
 		}
 
-		public IEnumerator<T?> GetEnumerator ()
+		public new IEnumerator<T?> GetEnumerator ()
 		{
 			return System.Linq.Extensions.ToEnumerator_Dispose<T> (Iterator ());
 		}
@@ -960,7 +960,7 @@ public bool Remove (T item)
 			return true;
 		}
 
-		public static IList<T>? FromJniHandle (IntPtr handle, JniHandleOwnership transfer)
+		public new static IList<T>? FromJniHandle (IntPtr handle, JniHandleOwnership transfer)
 		{
 			if (handle == IntPtr.Zero)
 				return null;

src/Mono.Android/Android.Runtime/JavaObject.cs

@@ -104,11 +104,11 @@ public override int GetHashCode ()
 			return inst.GetHashCode ();
 		}
 
-		public override string? ToString ()
+		public override string ToString ()
 		{
 			if (inst == null)
 				return "";
-			return inst.ToString ();
+			return inst.ToString () ?? "";
 		}
 	}
 }

src/Mono.Android/Android.Runtime/JavaProxyThrowable.cs

@@ -11,7 +11,7 @@ namespace Android.Runtime {
 
 	sealed class JavaProxyThrowable : Java.Lang.Error {
 
-		public  readonly Exception InnerException;
+		public  readonly new Exception InnerException;
 
 		JavaProxyThrowable (string message, Exception innerException)
 			: base (message)