diff --git a/src/Microsoft.Android.Sdk.ILLink/PreserveApplications.cs b/src/Microsoft.Android.Sdk.ILLink/PreserveApplications.cs
index 99ca8df9384..5e3e1b0c44d 100644
--- a/src/Microsoft.Android.Sdk.ILLink/PreserveApplications.cs
+++ b/src/Microsoft.Android.Sdk.ILLink/PreserveApplications.cs
@@ -66,7 +66,12 @@ void PreserveTypeProperty (CustomAttribute attribute, string property)
 			if (!attribute.HasProperties)
 				return;
 
-			var type_ref = (TypeReference) attribute.Properties.First (p => p.Name == property).Argument.Value;
+			// NOTE: CustomAttributeNamedArgument is a struct
+			var named_arg = attribute.Properties.FirstOrDefault (p => p.Name == property);
+			if (named_arg.Name == null)
+				return;
+
+			var type_ref = named_arg.Argument.Value as TypeReference;
 			if (type_ref == null)
 				return;
 
diff --git a/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest2.cs b/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest2.cs
index 2394f7804d9..6cf5a5a88a0 100644
--- a/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest2.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest2.cs
@@ -1083,9 +1083,11 @@ public void BuildAfterMultiDexIsNotRequired ()
 		}
 
 		[Test]
-		public void CustomApplicationClassAndMultiDex ()
+		public void CustomApplicationClassAndMultiDex ([Values (true, false)] bool isRelease)
 		{
 			var proj = CreateMultiDexRequiredApplication ();
+			proj.IsRelease = isRelease;
+			proj.TrimModeRelease = TrimMode.Full;
 			proj.SetProperty ("AndroidEnableMultiDex", "True");
 			proj.Sources.Add (new BuildItem ("Compile", "CustomApp.cs") { TextContent = () => @"
 using System;
@@ -1108,7 +1110,7 @@ public override void OnCreate()
         }
     }
 }" });
-			using (var b = CreateApkBuilder ("temp/CustomApplicationClassAndMultiDex")) {
+			using (var b = CreateApkBuilder ()) {
 				Assert.IsTrue (b.Build (proj), "Build should have succeeded.");
 				Assert.IsFalse (b.LastBuildOutput.ContainsText ("Duplicate zip entry"), "Should not get warning about [META-INF/MANIFEST.MF]");
 				var customAppContent = File.ReadAllText (Path.Combine (Root, b.ProjectDirectory, proj.IntermediateOutputPath, "android", "src", "com", "foxsports", "test", "CustomApp.java"));
diff --git a/src/Xamarin.Android.Build.Tasks/Utilities/ManifestDocumentElement.cs b/src/Xamarin.Android.Build.Tasks/Utilities/ManifestDocumentElement.cs
index 3139f366fb8..ef3a475a3e4 100644
--- a/src/Xamarin.Android.Build.Tasks/Utilities/ManifestDocumentElement.cs
+++ b/src/Xamarin.Android.Build.Tasks/Utilities/ManifestDocumentElement.cs
@@ -29,10 +29,12 @@ public static string ToString (TypeDefinition typeDef, TypeDefinitionCache cache
 
 		public static TypeDefinition ResolveType (string type, ICustomAttributeProvider provider, IAssemblyResolver resolver)
 		{
+			if (type == null)
+				throw new ArgumentException ("Type resolution support requires a non-null Type.", nameof (type));
 			if (provider == null)
-				throw new ArgumentException ("Type resolution support requires an AssemblyDefinition or TypeDefinition.", "provider");
+				throw new ArgumentException ("Type resolution support requires an AssemblyDefinition or TypeDefinition.", nameof (provider));
 			if (resolver == null)
-				throw new ArgumentException ("Type resolution support requires a IAssemblyResolver.", "resolver");
+				throw new ArgumentException ("Type resolution support requires a IAssemblyResolver.", nameof (resolver));
 
 			// `type` is either a "bare" type "Foo.Bar", or an
 			// assembly-qualified type "Foo.Bar, AssemblyName [Version=...]?".