\n /// [CanBeNull] object Test() => null;\n /// \n /// void UseTest() {\n /// var p = Test();\n /// var s = p.ToString(); // Warning: Possible 'System.NullReferenceException'\n /// }\n /// \n /// [NotNull] object Foo() {\n /// return null; // Warning: Possible 'null' assignment\n /// }\n /// \n /// public void Foo([ItemNotNull]List<string> books)\n /// {\n /// foreach (var book in books) {\n /// if (book != null) // Warning: Expression is always true\n /// Console.WriteLine(book.ToUpper());\n /// }\n /// }\n /// \n /// public void Foo([ItemCanBeNull]List<string> books)\n /// {\n /// foreach (var book in books)\n /// {\n /// // Warning: Possible 'System.NullReferenceException'\n /// Console.WriteLine(book.ToUpper());\n /// }\n /// }\n /// \n /// [StringFormatMethod(\"message\")]\n /// void ShowError(string message, params object[] args) { /* do something */ }\n /// \n /// void Foo() {\n /// ShowError(\"Failed: {0}\"); // Warning: Non-existing argument in format string\n /// }\n /// \n /// namespace TestNamespace\n /// {\n /// public class Constants\n /// {\n /// public static int INT_CONST = 1;\n /// public const string STRING_CONST = \"1\";\n /// }\n ///\n /// public class Class1\n /// {\n /// [ValueProvider(\"TestNamespace.Constants\")] public int myField;\n /// public void Foo([ValueProvider(\"TestNamespace.Constants\")] string str) { }\n ///\n /// public void Test()\n /// {\n /// Foo(/*try completion here*/);//\n /// myField = /*try completion here*/\n /// }\n /// }\n /// }\n /// \n /// void Foo([ValueRange(0, 100)] int value) {\n /// if (value == -1) { // Warning: Expression is always 'false'\n /// ...\n /// }\n /// }\n /// \n /// void Foo([NonNegativeValue] int value) {\n /// if (value == -1) { // Warning: Expression is always 'false'\n /// ...\n /// }\n /// }\n /// \n /// void Foo(string param) {\n /// if (param == null)\n /// throw new ArgumentNullException(\"par\"); // Warning: Cannot resolve symbol\n /// }\n /// \n /// public class Foo : INotifyPropertyChanged {\n /// public event PropertyChangedEventHandler PropertyChanged;\n /// \n /// [NotifyPropertyChangedInvocator]\n /// protected virtual void NotifyChanged(string propertyName) { ... }\n ///\n /// string _name;\n /// \n /// public string Name {\n /// get { return _name; }\n /// set { _name = value; NotifyChanged(\"LastName\"); /* Warning */ }\n /// }\n /// }\n /// \n /// Examples of generated notifications:\n /// Function Definition Table syntax:
\n ///\n /// [ContractAnnotation(\"=> halt\")]\n /// public void TerminationMethod()\n /// \n /// [ContractAnnotation(\"null <= param:null\")] // reverse condition syntax\n /// public string GetName(string surname)\n /// \n /// [ContractAnnotation(\"s:null => true\")]\n /// public bool IsNullOrEmpty(string s) // string.IsNullOrEmpty()\n /// \n /// // A method that returns null if the parameter is null,\n /// // and not null if the parameter is not null\n /// [ContractAnnotation(\"null => null; notnull => notnull\")]\n /// public object Transform(object data)\n /// \n /// [ContractAnnotation(\"=> true, result: notnull; => false, result: null\")]\n /// public bool TryParse(string s, out Person result)\n /// \n /// [LocalizationRequiredAttribute(true)]\n /// class Foo {\n /// string str = \"my string\"; // Warning: Localizable string\n /// }\n /// \n /// [CannotApplyEqualityOperator]\n /// class NoEquality { }\n /// \n /// class UsesNoEquality {\n /// void Test() {\n /// var ca1 = new NoEquality();\n /// var ca2 = new NoEquality();\n /// if (ca1 != null) { // OK\n /// bool condition = ca1 == ca2; // Warning\n /// }\n /// }\n /// }\n /// \n /// [BaseTypeRequired(typeof(IComponent)] // Specify requirement\n /// class ComponentAttribute : Attribute { }\n /// \n /// [Component] // ComponentAttribute requires implementing IComponent interface\n /// class MyComponent : IComponent { }\n /// \n /// [Pure] int Multiply(int x, int y) => x * y;\n /// \n /// void M() {\n /// Multiply(123, 42); // Warning: Return value of pure method is not used\n /// }\n /// [MustUseReturnValue(\"Use the return value to...\")].\n /// \n /// class Foo {\n /// [ProvidesContext] IBarService _barService = ...;\n /// \n /// void ProcessNode(INode node) {\n /// DoSomething(node, node.GetGlobalServices().Bar);\n /// // ^ Warning: use value of '_barService' field\n /// }\n /// }\n /// \n /// [SourceTemplate]\n /// public static void forEach<T>(this IEnumerable<T> xs) {\n /// foreach (var x in xs) {\n /// //$ $END$\n /// }\n /// }\n /// \n /// \n /// [SourceTemplate, Macro(Target = \"item\", Expression = \"suggestVariableName()\")]\n /// public static void forEach<T>(this IEnumerable<T> collection) {\n /// foreach (var item in collection) {\n /// //$ $END$\n /// }\n /// }\n /// \n /// Applying the attribute on a template method parameter:\n /// \n /// [SourceTemplate]\n /// public static void something(this Entity x, [Macro(Expression = \"guid()\", Editable = -1)] string newguid) {\n /// /*$ var $x$Id = \"$newguid$\" + x.ToString();\n /// x.DoSomething($x$Id); */\n /// }\n /// \n /// \n /// [ActionName(\"Foo\")]\n /// public ActionResult Login(string returnUrl) {\n /// ViewBag.ReturnUrl = Url.Action(\"Foo\"); // OK\n /// return RedirectToAction(\"Bar\"); // Error: Cannot resolve action\n /// }\n /// \n /// public class MyStringCollection : List<string>\n /// {\n /// [CollectionAccess(CollectionAccessType.Read)]\n /// public string GetFirstString()\n /// {\n /// return this.ElementAt(0);\n /// }\n /// }\n /// class Test\n /// {\n /// public void Foo()\n /// {\n /// // Warning: Contents of the collection is never updated\n /// var col = new MyStringCollection();\n /// string x = col.GetFirstString();\n /// }\n /// }\n /// \n /// static void ThrowIfNull<T>([NoEnumeration] T v, string n) where T : class\n /// {\n /// // custom check for null but no enumeration\n /// }\n /// \n /// void Foo(IEnumerable<string> values)\n /// {\n /// ThrowIfNull(values, nameof(values));\n /// var x = values.ToList(); // No warnings about multiple enumeration\n /// }\n ///