diff --git a/mcs/errors/CS0101-7-2.cs b/mcs/errors/CS0101-7-2.cs
new file mode 100644
index 0000000000000..90cf116b98789
--- /dev/null
+++ b/mcs/errors/CS0101-7-2.cs
@@ -0,0 +1,5 @@
+// CS0101: The namespace `global::' already contains a definition for `Test'
+// Line: 5
+// Compiler options: CS0101-7-2.cs
+
+class Test {}
diff --git a/mcs/errors/cs0101-7.cs b/mcs/errors/cs0101-7.cs
new file mode 100644
index 0000000000000..90cf116b98789
--- /dev/null
+++ b/mcs/errors/cs0101-7.cs
@@ -0,0 +1,5 @@
+// CS0101: The namespace `global::' already contains a definition for `Test'
+// Line: 5
+// Compiler options: CS0101-7-2.cs
+
+class Test {}
diff --git a/mcs/mcs/class.cs b/mcs/mcs/class.cs
index 2ea5321014f63..dc173d7a3ac12 100644
--- a/mcs/mcs/class.cs
+++ b/mcs/mcs/class.cs
@@ -70,6 +70,12 @@ public TypeContainer (TypeContainer parent, MemberName name, Attributes attrs, M
 			}
 		}
 
+		public Dictionary<string, MemberCore> DefinedNames {
+			get {
+				return defined_names;
+			}
+		}
+
 		public TypeDefinition PartialContainer {
 			get {
 				return main_container;
diff --git a/mcs/mcs/namespace.cs b/mcs/mcs/namespace.cs
index 02f1f2159eaa6..c26fc0a3c87ad 100644
--- a/mcs/mcs/namespace.cs
+++ b/mcs/mcs/namespace.cs
@@ -799,8 +799,10 @@ public override void AddTypeContainer (TypeContainer tc)
 				name = mn.Name;
 			}
 
+			var names_container = Parent == null ? Module : (TypeContainer) this;
+
 			MemberCore mc;
-			if (defined_names.TryGetValue (name, out mc)) {
+			if (names_container.DefinedNames.TryGetValue (name, out mc)) {
 				if (tc is NamespaceContainer && mc is NamespaceContainer) {
 					containers.Add (tc);
 					return;
@@ -814,7 +816,7 @@ public override void AddTypeContainer (TypeContainer tc)
 						GetSignatureForError (), mn.GetSignatureForError ());
 				}
 			} else {
-				defined_names.Add (name, tc);
+				names_container.DefinedNames.Add (name, tc);
 			}
 
 			base.AddTypeContainer (tc);