[mcs] Consider nested types when looking for potential types via usin…

…g static. Fixes #29044

mcs/errors/cs0104-5.cs

@@ -0,0 +1,35 @@
+// CS0104: `N' is an ambiguous reference between `C.N' and `A.T.N'
+// Line: 32
+
+namespace A
+{
+	public class T
+	{
+		public class N
+		{
+
+		}
+	}
+}
+
+namespace C
+{
+	struct N
+	{
+
+	}
+}
+
+namespace B
+{
+	using static A.T;
+	using C;
+
+	static class Program
+	{
+		static void Main ()
+		{
+			var u = new N ();
+		}
+	}
+}

mcs/errors/cs0246-35.cs

@@ -0,0 +1,23 @@
+// CS0246: The type or namespace name `B' could not be found. Are you missing an assembly reference?
+// Line: 21
+
+using static A;
+
+class A : B
+{
+}
+
+class P
+{
+	public class N<T>
+	{
+	}
+}
+
+class Test
+{
+	public static void Main ()
+	{
+		var n = default (N<int>);
+	}
+}

mcs/mcs/namespace.cs

@@ -1147,10 +1147,7 @@ FullNamedExpression Lookup (string name, int arity, LookupMode mode, Location lo
 				var better = Namespace.IsImportedTypeOverride (Module, texpr_match.Type, texpr_fne.Type);
 				if (better == null) {
 					if (mode == LookupMode.Normal) {
-						Compiler.Report.SymbolRelatedToPreviousError (texpr_match.Type);
-						Compiler.Report.SymbolRelatedToPreviousError (texpr_fne.Type);
-						Compiler.Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
-							name, texpr_match.GetSignatureForError (), texpr_fne.GetSignatureForError ());
+						Error_AmbiguousReference (name, texpr_match, texpr_fne, loc);
 					}
 
 					return match;
@@ -1160,9 +1157,56 @@ FullNamedExpression Lookup (string name, int arity, LookupMode mode, Location lo
 					match = texpr_fne;
 			}
 
+			if (types_using_table != null) {
+				foreach (var using_type in types_using_table) {
+					var members = MemberCache.FindMembers (using_type, name, true);
+					if (members == null)
+						continue;
+
+					foreach (var member in members) {
+						if (arity > 0 && member.Arity != arity)
+							continue;
+
+						if ((member.Kind & MemberKind.NestedMask) != 0) {
+							// non-static nested type is included with using static
+						} else {
+							if ((member.Modifiers & Modifiers.STATIC) == 0)
+								continue;
+
+							if ((member.Modifiers & Modifiers.METHOD_EXTENSION) != 0)
+								continue;
+
+							if (mode == LookupMode.Normal)
+								throw new NotImplementedException ();
+
+							return null;
+						}
+
+						fne = new TypeExpression ((TypeSpec) member, loc);
+						if (match == null) {
+							match = fne;
+							continue;
+						}
+
+						if (mode == LookupMode.Normal) {
+							Error_AmbiguousReference (name, match, fne, loc);
+						}
+					}
+				}
+			}
+
 			return match;
 		}
 
+		void Error_AmbiguousReference (string name, FullNamedExpression a, FullNamedExpression b, Location loc)
+		{
+			var report = Compiler.Report;
+			report.SymbolRelatedToPreviousError (a.Type);
+			report.SymbolRelatedToPreviousError (b.Type);
+			report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
+				name, a.GetSignatureForError (), b.GetSignatureForError ());
+		}
+
 		public static Expression LookupStaticUsings (IMemberContext mc, string name, int arity, Location loc)
 		{
 			for (var m = mc.CurrentMemberDefinition; m != null; m = m.Parent) {
@@ -1175,26 +1219,27 @@ public static Expression LookupStaticUsings (IMemberContext mc, string name, int
 				if (nc.types_using_table != null) {
 					foreach (var using_type in nc.types_using_table) {
 						var members = MemberCache.FindMembers (using_type, name, true);
-						if (members != null) {
-							foreach (var member in members) {
-								if ((member.Kind & MemberKind.NestedMask) != 0) {
-									// non-static nested type is included with using static
-								} else {
-									if ((member.Modifiers & Modifiers.STATIC) == 0)
-										continue;
-
-									if ((member.Modifiers & Modifiers.METHOD_EXTENSION) != 0)
-										continue;
-								}
-
-								if (arity > 0 && member.Arity != arity)
+						if (members == null)
+							continue;
+
+						foreach (var member in members) {
+							if ((member.Kind & MemberKind.NestedMask) != 0) {
+								// non-static nested type is included with using static
+							} else {
+								if ((member.Modifiers & Modifiers.STATIC) == 0)
 									continue;
 
-								if (candidates == null)
-									candidates = new List<MemberSpec> ();
-
-								candidates.Add (member);
+								if ((member.Modifiers & Modifiers.METHOD_EXTENSION) != 0)
+									continue;
 							}
+
+							if (arity > 0 && member.Arity != arity)
+								continue;
+
+							if (candidates == null)
+								candidates = new List<MemberSpec> ();
+
+							candidates.Add (member);
 						}
 					}
 				}

mcs/tests/test-static-using-08.cs

@@ -0,0 +1,17 @@
+using static A;
+//using N = System.Int32;
+
+class A
+{
+	public class N
+	{
+	}
+}
+
+class Test
+{
+	public static void Main ()
+	{
+		N n = default (N); // Am I Int32 or A.N
+	}
+}

mcs/tests/test-static-using-10.cs

@@ -0,0 +1,24 @@
+namespace A
+{
+	public class T
+	{
+		public class N
+		{
+
+		}
+	}
+}
+
+namespace B
+{
+	using static A.T;
+
+	static class Program
+	{
+		static void Main ()
+		{
+			var t = typeof (N);
+			var u = new N ();
+		}
+	}
+}

mcs/tests/ver-il-net_4_5.xml

@@ -70158,13 +70158,50 @@
       </method>
     </type>
   </test>
+  <test name="test-static-using-08.cs">
+    <type name="A">
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="A+N">
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="Test">
+      <method name="Void Main()" attrs="150">
+        <size>4</size>
+      </method>
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+  </test>
   <test name="test-static-using-09.cs">
     <type name="Program">
       <method name="Void Main()" attrs="145">
         <size>9</size>
       </method>
     </type>
   </test>
+  <test name="test-static-using-10.cs">
+    <type name="A.T">
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="A.T+N">
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="B.Program">
+      <method name="Void Main()" attrs="145">
+        <size>19</size>
+      </method>
+    </type>
+  </test>
   <test name="test-var-01.cs">
     <type name="Test">
       <method name="Int32 Main()" attrs="150">