[Xamarin.Android.Build.Tasks] Invokers after abstracts in typemaps

src/Xamarin.Android.Build.Tasks/Utilities/TypeMapGenerator.cs

@@ -77,6 +77,11 @@ internal sealed class TypeMapDebugEntry
 			public TypeDefinition TypeDefinition;
 			public bool SkipInJavaToManaged;
 			public TypeMapDebugEntry DuplicateForJavaToManaged;
+
+			public override string ToString ()
+			{
+				return $"TypeMapDebugEntry{{JavaName={JavaName}, ManagedName={ManagedName}, JavaIndex={JavaIndex}, ManagedIndex={ManagedIndex}, SkipInJavaToManaged={SkipInJavaToManaged}, DuplicateForJavaToManaged={DuplicateForJavaToManaged}}}";
+			}
 		}
 
 		// Widths include the terminating nul character but not the padding!
@@ -305,13 +310,18 @@ void HandleDebugDuplicates (Dictionary<string, List<TypeMapDebugEntry>> javaDupl
 			if (!javaDuplicates.TryGetValue (entry.JavaName, out duplicates)) {
 				javaDuplicates.Add (entry.JavaName, new List<TypeMapDebugEntry> { entry });
 			} else {
-				duplicates.Add (entry);
 				TypeMapDebugEntry oldEntry = duplicates[0];
-				if (td.IsAbstract || td.IsInterface || oldEntry.TypeDefinition.IsAbstract || oldEntry.TypeDefinition.IsInterface) {
-					if (td.IsAssignableFrom (oldEntry.TypeDefinition, cache)) {
-						oldEntry.TypeDefinition = td;
-						oldEntry.ManagedName = GetManagedTypeName (td);
-					}
+				if ((td.IsAbstract || td.IsInterface) &&
+						!oldEntry.TypeDefinition.IsAbstract &&
+						!oldEntry.TypeDefinition.IsInterface &&
+						td.IsAssignableFrom (oldEntry.TypeDefinition, cache)) {
+					// We found the `Invoker` type *before* the declared type
+					// Fix things up so the abstract type is first, and the `Invoker` is considered a duplicate.
+					duplicates.Insert (0, entry);
+					oldEntry.SkipInJavaToManaged = false;
+				} else {
+					// ¯\_(ツ)_/¯
+					duplicates.Add (entry);
 				}
 			}
 		}

tests/Mono.Android-Tests/Java.Interop/JavaObjectExtensionsTests.cs

@@ -29,13 +29,14 @@ public void JavaCast_BaseToGenericWrapper ()
 		public void JavaCast_InterfaceCast ()
 		{
 			IntPtr g;
-			using (var n = new Java.Lang.Integer (42)) {
-				g = JNIEnv.NewGlobalRef (n.Handle);
+			using (var vp = global::Net.Dot.Android.Test.Example.ValueProvider) {
+				g = JNIEnv.NewGlobalRef (vp.Handle);
 			}
-			// We want a Java.Lang.Object so that we create an IComparableInvoker
+			// We want a Java.Lang.Object so that we create an IIValueProviderInvoker
 			// instead of just getting back the original instance.
 			using (var o = Java.Lang.Object.GetObject<Java.Lang.Object> (g, JniHandleOwnership.TransferGlobalRef)) {
-				var c = JavaObjectExtensions.JavaCast<Java.Lang.IComparable> (o);
+				var c = JavaObjectExtensions.JavaCast<global::Net.Dot.Android.Test.IValueProvider> (o);
+				Assert.AreEqual (42, c.Value);
 				c.Dispose ();
 			}
 		}
@@ -111,3 +112,7 @@ public MyObject (IntPtr handle, JniHandleOwnership transfer)
 	}
 }
 
+namespace Net.Dot.Android.Test {
+	partial class IValueProviderInvoker {
+	}
+}

tests/Mono.Android-Tests/Mono.Android-Test.Shared.projitems

@@ -120,6 +120,12 @@
       <Link>Assets\subfolder\asset2.txt</Link>
     </AndroidAsset>
   </ItemGroup>
+
+  <ItemGroup>
+    <AndroidJavaSource Include="$(MSBuildThisFileDirectory)java/net/dot/android/test/ValueProvider.java" />
+    <AndroidJavaSource Include="$(MSBuildThisFileDirectory)java/net/dot/android/test/Example.java" />
+  </ItemGroup>
+
   <ItemGroup>
     <Folder Include="$(MSBuildThisFileDirectory)LinkedAssets\" />
   </ItemGroup>

tests/Mono.Android-Tests/java/net/dot/android/test/Example.java

@@ -0,0 +1,12 @@
+package net.dot.android.test;
+
+public class Example {
+	public static ValueProvider getValueProvider() {
+		return new ValueProvider() {
+			@Override
+			public int getValue() {
+				return 42;
+			}
+		};
+	}
+}

tests/Mono.Android-Tests/java/net/dot/android/test/ValueProvider.java

@@ -0,0 +1,5 @@
+package net.dot.android.test;
+
+public interface ValueProvider {
+	int getValue();
+}