Revert "Revert "[TypeSystem] Specialized method now contains a flag specifying the""

This reverts commit b758539431.

ICSharpCode.NRefactory.CSharp/Resolver/OverloadResolution.cs

@@ -950,6 +950,8 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			if (member == null)
 				throw new InvalidOperationException();
 			
+			if (this.IsExtensionMethodInvocation && member is SpecializedMethod)
+				((SpecializedMethod)member).IsExtendedExtensionMethod = true;
 			return new CSharpInvocationResolveResult(
 				this.IsExtensionMethodInvocation ? new TypeResolveResult(member.DeclaringType) : targetResolveResult,
 				member,

ICSharpCode.NRefactory/TypeSystem/Implementation/SpecializedMethod.cs

@@ -154,6 +154,14 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			}
 		}
 
+		/// <summary>
+		/// Gets/Sets whether the method is an extension method that are being called using extension method syntax.
+		/// </summary>
+		public bool IsExtendedExtensionMethod {
+			get;
+			set;
+		}
+		
 		public override IMemberReference ToMemberReference()
 		{
 			// Pass the MethodTypeArguments to the SpecializingMemberReference only if