Add importing of netmodule

Mono.Cecil/Import.cs

@@ -521,14 +521,33 @@ protected IMetadataScope ImportScope (IMetadataScope scope)
 				return ImportReference ((AssemblyNameReference) scope);
 			case MetadataScopeType.ModuleDefinition:
 				if (scope == module) return scope;
-				return ImportReference (((ModuleDefinition) scope).Assembly.Name);
+				var moduleDefinition = (ModuleDefinition) scope;
+				if (moduleDefinition.Assembly == null)
+					return ImportReference (moduleDefinition);
+				else
+					return ImportReference (moduleDefinition.Assembly.Name);
 			case MetadataScopeType.ModuleReference:
-				throw new NotImplementedException ();
+					return ImportReference ((ModuleReference) scope);
 			}
 
 			throw new NotSupportedException ();
 		}
 
+		public virtual ModuleReference ImportReference (ModuleReference name)
+		{
+			Mixin.CheckName (name);
+
+			ModuleReference reference;
+			if (module.TryGetModuleReference (name, out reference))
+				return reference;
+
+			reference = new ModuleReference (name.Name);
+
+			module.ModuleReferences.Add (reference);
+
+			return reference;
+		}
+
 		public virtual AssemblyNameReference ImportReference (AssemblyNameReference name)
 		{
 			Mixin.CheckName (name);
@@ -771,6 +790,23 @@ public static bool TryGetAssemblyNameReference (this ModuleDefinition module, As
 			return false;
 		}
 
+		public static bool TryGetModuleReference (this ModuleDefinition module, ModuleReference name_reference, out ModuleReference module_reference)
+		{
+			var references = module.ModuleReferences;
+
+			for (int i = 0; i < references.Count; i++) {
+				var reference = references [i];
+				if (!Equals (name_reference, reference))
+					continue;
+
+				module_reference = reference;
+				return true;
+			}
+
+			module_reference = null;
+			return false;
+		}
+
 		static bool Equals (byte [] a, byte [] b)
 		{
 			if (ReferenceEquals (a, b))
@@ -808,5 +844,14 @@ static bool Equals (AssemblyNameReference a, AssemblyNameReference b)
 				return false;
 			return true;
 		}
+
+		static bool Equals (ModuleReference a, ModuleReference b)
+		{
+			if (ReferenceEquals (a, b))
+				return true;
+			if (a.Name != b.Name)
+				return false;
+			return true;
+		}
 	}
 }

Test/Mono.Cecil.Tests/ImportCecilTests.cs

@@ -286,6 +286,20 @@ public void ContextGenericTest ()
 			Assert.AreEqual ("Mono.Cecil.Tests.ImportCecilTests/Generic`1<TS> Mono.Cecil.Tests.ImportCecilTests/Generic`1<System.String>::ComplexGenericMethod<TS>(T,TS)", method.FullName);
 		}
 
+		[Test]
+		public void ImportTypeFromOtherModule ()
+		{
+			var fooModule = ModuleDefinition.CreateModule("Foo", ModuleKind.NetModule);
+			var foo = new TypeDefinition("", "Foo", 0, fooModule.TypeSystem.Object);
+			fooModule.Types.Add(foo);
+
+			var mainModule = ModuleDefinition.CreateModule("Main", ModuleKind.NetModule);
+			mainModule.ModuleReferences.Add(fooModule);
+			var program = new TypeDefinition("", "Program", TypeAttributes.Class, mainModule.TypeSystem.Object);
+			var importedFooType = mainModule.ImportReference(foo);
+			Assert.AreEqual ("Foo", importedFooType.FullName);
+		}
+
 		delegate void Emitter (ModuleDefinition module, MethodBody body);
 
 		static TDelegate Compile<TDelegate> (Emitter emitter, [CallerMemberName] string testMethodName = null)