Imported Upstream version 6.8.0.73

Former-commit-id: d18deab1b47cfd3ad8cba82b3f37d00eec2170af

mcs/class/corlib/Test/System/AttributeTest.cs

@@ -1252,6 +1252,27 @@ namespace MonoTests.System
 			Assert.AreEqual (1, attrs.Length);	
 		}
 
+		[Test]
+		public void GetCustomAttributesOnOpenGenericMethodOverride ()
+		{
+			// Regression test for https://github.com/mono/mono/issues/17278
+			/* The issue is in how we pass along the generic
+			 * instantiation.  So there are two parts here: we
+			 * start with a method on a GTD which has to decompose
+			 * into the GTD and it's instantiation with its own
+			 * generic parameters, and then we go up to its parent
+			 * and grandparent inflating and decomposing the
+			 * resulting instantiation. The instantiations keep
+			 * passing the last parameter as the number of
+			 * parameters shrinks so that the gparam index from the
+			 * original type is now out of bounds for the parent
+			 * and grandparent.  If we mess up, we'll get a
+			 * BadImageFormatException from the runtime. */
+			var m = typeof (Three<,,>).GetMethod ("Foo");
+			var attrs = Attribute.GetCustomAttributes(m, typeof(MyCAttr), true);
+			Assert.AreEqual (1, attrs.Length);
+		}
+
 		class EvtBase
 		{
 			public virtual event EventHandler Event {add {} remove {}}
@@ -1268,6 +1289,20 @@ namespace MonoTests.System
 			public override event EventHandler Event {add {} remove {}}
 		}
 
+		abstract class One<A> {
+			[MyCAttr]
+			public abstract A Foo ();
+		}
+
+		abstract class Two<X,Y> : One<Y> {
+		}
+
+		class Three<P,Q,R> : Two<Q,R> {
+			public override R Foo () {
+				throw new Exception ("Doesn't matter");
+			}
+		}
+
 		[Test] //Regression test for #662867
 		public void GetCustomAttributesOnEventOverride ()
 		{