From e8417c18fe9d0467669cfb388aa51acd79b52fc3 Mon Sep 17 00:00:00 2001
From: Thays Grazia <thaystg@gmail.com>
Date: Mon, 2 Dec 2019 13:20:00 -0300
Subject: [PATCH] [DIM] Fix behavior when there is an override of a method in a
 generic interface.  (mono/mono#17963)

* Fix behavior when there is an override of a method in a generic interface.
Fixes mono/mono#17869



Commit migrated from https://github.com/mono/mono/commit/3834be3d2242312a6284f89ed77b60ff8b2327ab
---
 src/mono/mono/metadata/class-init.c |  2 ++
 src/mono/mono/tests/Makefile.am     |  1 +
 src/mono/mono/tests/dim-generic.cs  | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 src/mono/mono/tests/dim-generic.cs

diff --git a/src/mono/mono/metadata/class-init.c b/src/mono/mono/metadata/class-init.c
index 7ffda47..7bdd00a 100644
--- a/src/mono/mono/metadata/class-init.c
+++ b/src/mono/mono/metadata/class-init.c
@@ -3030,6 +3030,8 @@ mono_class_setup_vtable_general (MonoClass *klass, MonoMethod **overrides, int o
 			if (decl->is_inflated) {
 				override = mono_class_inflate_generic_method_checked (override, mono_method_get_context (decl), error);
 				mono_error_assert_ok (error);
+			} else if (mono_class_is_gtd (override->klass)) {
+				override = mono_class_inflate_generic_method_full_checked (override, ic, mono_class_get_context (ic), error);
 			}
 			if (!apply_override (klass, ic, vtable, decl, override, &override_map, &override_class_map, &conflict_map))
 				goto fail;
diff --git a/src/mono/mono/tests/Makefile.am b/src/mono/mono/tests/Makefile.am
index 45871d6..888f81f 100755
--- a/src/mono/mono/tests/Makefile.am
+++ b/src/mono/mono/tests/Makefile.am
@@ -384,6 +384,7 @@ TESTS_CS_SRC=		\
 	reflection.cs		\
 	interface.cs		\
 	interface-2.cs		\
+	dim-generic.cs		\
 	iface.cs		\
 	iface2.cs		\
 	iface3.cs		\
diff --git a/src/mono/mono/tests/dim-generic.cs b/src/mono/mono/tests/dim-generic.cs
new file mode 100644
index 0000000..c6254f0
--- /dev/null
+++ b/src/mono/mono/tests/dim-generic.cs
@@ -0,0 +1,34 @@
+using System;
+
+
+interface IBaseThingy
+{
+	int Foo ();
+}
+
+interface INativeThingy<T> : IBaseThingy
+{
+	int IBaseThingy.Foo () {
+		return 0;
+        }
+}
+
+class NativeThingy : INativeThingy<string>
+{
+}
+
+public class Test
+{
+	public static int test_0_dim_override()
+	{
+		var thingy = new NativeThingy ();
+		var ithingy = (IBaseThingy)thingy;
+		int i = ithingy.Foo ();
+		return i;
+    }
+
+    public static int Main (string[] args) {
+		return TestDriver.RunTests (typeof (Test), args);
+	}
+
+}
-- 
2.7.4