Don't show 'Method with optional parameter is hidden by overload' issue if the overloads have different type parameters.

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/MethodOverloadHidesOptionalParameterIssue.cs

@@ -64,7 +64,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				if (method.Parameters.Count == 0 || !method.Parameters.Last ().IsOptional)
 					return;
 
-				var overloads = method.DeclaringType.GetMembers (m => m.Name == method.Name).OfType<IMethod> ()
+				var overloads = method.DeclaringType.GetMethods(m => m.Name == method.Name && m.TypeParameters.Count == method.TypeParameters.Count)
 					.ToArray ();
 
 				var parameterNodes = methodDeclaration.Parameters.ToArray();

ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/MethodOverloadHidesOptionalParameterIssueTests.cs

@@ -68,6 +68,18 @@ class TestClass
 {
 	void TestMethod (int a, int b = 1, int c = 1)
 	{ }
+}";
+			Test<MethodOverloadHidesOptionalParameterIssue> (input, 0);
+		}
+		
+		[Test]
+		public void TestNoIssue_Generics ()
+		{
+			var input = @"
+class TestClass
+{
+	void TestMethod (object obj) { }
+	void TestMethod<T> (object obj, int arg = 0) { }
 }";
 			Test<MethodOverloadHidesOptionalParameterIssue> (input, 0);
 		}