[CanBeNull] object Test() => null;
void UseTest() {
var p = Test();
var s = p.ToString(); // Warning: Possible 'System.NullReferenceException'
}
[NotNull] object Foo() {
return null; // Warning: Possible 'null' assignment
}
[StringFormatMethod("message")]
void ShowError(string message, params object[] args) { /* do something */ }
void Foo() {
ShowError("Failed: {0}"); // Warning: Non-existing argument in format string
}
void Foo(string param) {
if (param == null)
throw new ArgumentNullException("par"); // Warning: Cannot resolve symbol
}
public class Foo : INotifyPropertyChanged {
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void NotifyChanged(string propertyName) { ... }
string _name;
public string Name {
get { return _name; }
set { _name = value; NotifyChanged("LastName"); /* Warning */ }
}
}
Examples of generated notifications:
Function Definition Table syntax:
[ContractAnnotation("=> halt")]
public void TerminationMethod()
[ContractAnnotation("halt <= condition: false")]
public void Assert(bool condition, string text) // regular assertion method
[ContractAnnotation("s:null => true")]
public bool IsNullOrEmpty(string s) // string.IsNullOrEmpty()
// A method that returns null if the parameter is null,
// and not null if the parameter is not null
[ContractAnnotation("null => null; notnull => notnull")]
public object Transform(object data)
[ContractAnnotation("=> true, result: notnull; => false, result: null")]
public bool TryParse(string s, out Person result)
[LocalizationRequiredAttribute(true)]
class Foo {
string str = "my string"; // Warning: Localizable string
}
[CannotApplyEqualityOperator]
class NoEquality { }
class UsesNoEquality {
void Test() {
var ca1 = new NoEquality();
var ca2 = new NoEquality();
if (ca1 != null) { // OK
bool condition = ca1 == ca2; // Warning
}
}
}
[BaseTypeRequired(typeof(IComponent)] // Specify requirement
class ComponentAttribute : Attribute { }
[Component] // ComponentAttribute requires implementing IComponent interface
class MyComponent : IComponent { }
[Pure] int Multiply(int x, int y) => x * y;
void M() {
Multiply(123, 42); // Waring: Return value of pure method is not used
}
class Foo {
[ProvidesContext] IBarService _barService = ...;
void ProcessNode(INode node) {
DoSomething(node, node.GetGlobalServices().Bar);
// ^ Warning: use value of '_barService' field
}
}
[SourceTemplate]
public static void forEach<T>(this IEnumerable<T> xs) {
foreach (var x in xs) {
//$ $END$
}
}
[SourceTemplate, Macro(Target = "item", Expression = "suggestVariableName()")]
public static void forEach<T>(this IEnumerable<T> collection) {
foreach (var item in collection) {
//$ $END$
}
}
Applying the attribute on a template method parameter:
[SourceTemplate]
public static void something(this Entity x, [Macro(Expression = "guid()", Editable = -1)] string newguid) {
/*$ var $x$Id = "$newguid$" + x.ToString();
x.DoSomething($x$Id); */
}
[ActionName("Foo")]
public ActionResult Login(string returnUrl) {
ViewBag.ReturnUrl = Url.Action("Foo"); // OK
return RedirectToAction("Bar"); // Error: Cannot resolve action
}