Tests: Add explicit interface implementation tests

Il2CppTests/TestSources/ExplicitInterfaces.cs

@@ -0,0 +1,59 @@
+/*
+    Copyright 2017-2019 Katy Coe - http://www.hearthcode.org - http://www.djkaty.com
+
+    All rights reserved.
+*/
+
+using System.Collections.Generic;
+
+#pragma warning disable CS0169
+namespace Il2CppTests.TestSources
+{
+    // See: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/interfaces/explicit-interface-implementation
+
+    interface IControl
+    {
+        void Paint();
+    }
+
+    interface ISurface
+    {
+        void Paint();
+    }
+
+    internal class Test : IControl, ISurface
+    {
+        // No access modifiers on explicit interface implementation
+        void IControl.Paint() {}
+        void ISurface.Paint() {}
+    }
+
+    interface ILeft
+    {
+        int P { get; }
+    }
+
+    interface IRight
+    {
+        int P();
+    }
+
+    internal class Middle : ILeft, IRight
+    {
+        // One or the other has to be explicitly implemented to resolve naming conflicts
+        public int P() => default;
+        int ILeft.P => default;
+    }
+
+    // Generic implementation
+    interface IGeneric<in T>
+    {
+        void GenericMethod(T t);
+    }
+
+    internal class ImplementsGenericInterface : IGeneric<KeyValuePair<int, double>>
+    {
+        void IGeneric<KeyValuePair<int, double>>.GenericMethod(KeyValuePair<int, double> t) {}
+    }
+}
+#pragma warning restore CS0169