Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

mcs/tools/linker/Descriptors/System.xml

@@ -13,6 +13,7 @@
 		<type fullname="System.Net.SocketAddress" />
 		<type fullname="System.Net.Sockets.LingerOption" />
 		<type fullname="System.Net.Sockets.Socket" />
+		<type fullname="System.Net.Sockets.MulticastOption" preserve="fields" />
 		<type fullname="System.Net.Sockets.Socket/SocketAsyncResult" preserve="fields" />
 		<type fullname="System.Net.Sockets.SocketException" />
 	</assembly>

mcs/tools/linker/Mono.Linker.Steps/MarkStep.cs

@@ -269,11 +269,32 @@ namespace Mono.Linker.Steps {
 
 		void MarkIfType (CustomAttributeArgument argument)
 		{
-			if (argument.Type.FullName != "System.Type")
-				return;
+			var at = argument.Type;
+			if (at.IsArray) {
+				var et = at.GetElementType ();
+				if (et.Namespace != "System" || et.Name != "Type")
+					return;
 
-			MarkType (argument.Type);
-			MarkType ((TypeReference) argument.Value);
+				MarkType (et);
+				foreach (var cac in (CustomAttributeArgument[]) argument.Value)
+					MarkWithResolvedScope ((TypeReference) cac.Value);
+			} else if (at.Namespace == "System" && at.Name == "Type") {
+				MarkType (argument.Type);
+				MarkWithResolvedScope ((TypeReference) argument.Value);
+			}
+		}
+
+		// custom attributes encoding means it's possible to have a scope that will point into a PCL facade
+		// even if we (just before saving) will resolve all type references (bug #26752)
+		void MarkWithResolvedScope (TypeReference type)
+		{
+			// we cannot set the Scope of a TypeSpecification so there's no point in resolving it
+			if ((type == null) || (type is TypeSpecification))
+				return;
+			var td = type.Resolve ();
+			if (td != null)
+				type.Scope = td.Scope;
+			MarkType (type);
 		}
 
 		protected bool CheckProcessed (IMetadataTokenProvider provider)