Fixed accessibility check for protected members in outer classes.

ICSharpCode.NRefactory.CSharp/Resolver/MemberLookup.cs

@@ -66,7 +66,13 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		public bool IsProtectedAccessAllowed(IType targetType)
 		{
 			ITypeDefinition typeDef = targetType.GetDefinition();
-			return typeDef != null && typeDef.IsDerivedFrom(currentTypeDefinition);
+			if (typeDef == null)
+				return false;
+			for (ITypeDefinition c = currentTypeDefinition; c != null; c = c.DeclaringTypeDefinition) {
+				if (typeDef.IsDerivedFrom(c))
+					return true;
+			}
+			return false;
 		}
 		
 		/// <summary>
@@ -126,7 +132,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				
 				// PERF: this might hurt performance as this method is called several times (once for each member)
 				// make sure resolving base types is cheap (caches?) or cache within the MemberLookup instance
-				if (allowProtectedAccess && currentTypeDefinition.IsDerivedFrom(entity.DeclaringTypeDefinition))
+				if (allowProtectedAccess && t.IsDerivedFrom(entity.DeclaringTypeDefinition))
 					return true;
 			}
 			return false;

ICSharpCode.NRefactory.Tests/CSharp/Resolver/MemberLookupTests.cs

@@ -261,5 +261,21 @@ public struct C<T> {
 			Assert.AreEqual("C`1[[`0]]", rr.Arguments[0].Type.ReflectionName);
 			Assert.AreEqual("C`1[[`0]]", rr.Arguments[1].Type.ReflectionName);
 		}
+		
+		[Test]
+		public void ProtectedFieldInOuterClass()
+		{
+			string program = @"using System;
+class Base {
+  protected int X;
+}
+class Derived : Base {
+  class Inner {
+     public int M(Derived d) { return $d.X$; }
+}}";
+			var rr = Resolve<MemberResolveResult>(program);
+			Assert.IsFalse(rr.IsError);
+			Assert.AreEqual("Base.X", rr.Member.FullName);
+		}
 	}
 }