diff --git a/ICSharpCode.NRefactory.CSharp/Parser/mcs/ecore.cs b/ICSharpCode.NRefactory.CSharp/Parser/mcs/ecore.cs
index 65ae6c2fb3..05d2872c8a 100644
--- a/ICSharpCode.NRefactory.CSharp/Parser/mcs/ecore.cs
+++ b/ICSharpCode.NRefactory.CSharp/Parser/mcs/ecore.cs
@@ -751,6 +751,9 @@ namespace Mono.CSharp {
 
 		public virtual void Error_OperatorCannotBeApplied (ResolveContext rc, Location loc, string oper, TypeSpec t)
 		{
+			if (t == InternalType.ErrorType)
+				return;
+
 			rc.Report.Error (23, loc, "The `{0}' operator cannot be applied to operand of type `{1}'",
 				oper, t.GetSignatureForError ());
 		}
@@ -4728,7 +4731,7 @@ namespace Mono.CSharp {
 			} else if (IsDelegateInvoke) {
 				ec.Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
 					DelegateType.GetSignatureForError ());
-			} else {
+			} else if (a.Type != InternalType.ErrorType) {
 				ec.Report.SymbolRelatedToPreviousError (method);
 				ec.Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
 					method.GetSignatureForError ());
@@ -4745,7 +4748,7 @@ namespace Mono.CSharp {
 				else
 					ec.Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
 						index, Parameter.GetModifierSignature (mod));
-			} else if (a.Expr != ErrorExpression.Instance) {
+			} else if (a.Type != InternalType.ErrorType) {
 				string p1 = a.GetSignatureForError ();
 				string p2 = TypeManager.CSharpName (paramType);
 
diff --git a/ICSharpCode.NRefactory.CSharp/Parser/mcs/expression.cs b/ICSharpCode.NRefactory.CSharp/Parser/mcs/expression.cs
index da92cae7fa..4ad2473d69 100644
--- a/ICSharpCode.NRefactory.CSharp/Parser/mcs/expression.cs
+++ b/ICSharpCode.NRefactory.CSharp/Parser/mcs/expression.cs
@@ -8422,8 +8422,11 @@ namespace Mono.CSharp
 				return new IndexerExpr (indexers, type, this);
 			}
 
-			ec.Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
-				type.GetSignatureForError ());
+			if (type != InternalType.ErrorType) {
+				ec.Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
+					type.GetSignatureForError ());
+			}
+
 			return null;
 		}
 
diff --git a/ICSharpCode.NRefactory.Tests/CSharp/CodeCompletion/CodeCompletionBugTests.cs b/ICSharpCode.NRefactory.Tests/CSharp/CodeCompletion/CodeCompletionBugTests.cs
index b2a7b4b5dc..3fb1c75631 100644
--- a/ICSharpCode.NRefactory.Tests/CSharp/CodeCompletion/CodeCompletionBugTests.cs
+++ b/ICSharpCode.NRefactory.Tests/CSharp/CodeCompletion/CodeCompletionBugTests.cs
@@ -4579,6 +4579,24 @@ class MainClass
 			Assert.IsNotNull (provider.Find ("Math"), "'Math' not found.");
 		}
 		
+		[Ignore("Mcs bug")]
+		[Test()]
+		public void TestConditionalExpression ()
+		{
+			CompletionDataList provider = CreateProvider (
+@"using System;
+
+class MainClass
+{
+	public static void Main (string[] args)
+	{
+		int a;
+		$a = true ? System.$
+	}
+}
+");
+			Assert.IsNotNull (provider.Find ("Math"), "'Math' not found.");
+		}
 		
 		/// <summary>
 		/// Bug 3655 - Autocompletion does not work for the assembly attribute [assembly: System.Runtime.CompilerServices.InternalsVisibleTo("MyExternalAssembly")]