code-contracts

I am implementing my own ArrayList for school purposes, but to spice up things a bit I'm trying to use C# 4.0 Code Contracts. All was fine until I needed to add Contracts to the constructors. Should I add Contract.Ensures() in the empty parameter constructor? public ArrayList(int capacity) { Contract.Requires(capacity > 0); Contract.Ensures(Size == capacity); _array = new T[capacity]; } public ArrayList() : this(32) { Contract.Ensures(Size == 32); } I'd say yes, each method should have a well defined contract. On the other hand, why put it if it's just delegating work to the "main" constructor

Consider the following "Safe" program: internal class Safe { public static void SafeMethodWillNeverThrow() { try { var something = ThrowsNewException(); Func<int, string> x = p => something.ToString(); } catch (Exception) { } } private static object ThrowsNewException() { throw new Exception(); } public static void Main() { SafeMethodWillNeverThrow(); } } It should never complete with an exception. But why it fails when I run it? Why SafeMethodWillNeverThrow() throws the Exception? Before testing this code please read the answer below. It is because you have Code Contracts Runtime Contract

I have the following scenario: public interface ISomething { void DoStuff(); //... } public class Something : ISomething { private readonly ISomethingElse _somethingElse; //... public Something (ISomethingElse somethingElse) { Contract.Requires(somethingElse != null); _somethingElse = somethingElse; } public void DoStuff() { // *1* Please look at explanation / question below _somethingElse.DoThings(); } } At line 1 and with the static checker on, I'll get a warning saying that _somethingElse is possibly null, and if I add a contract it will give me the error [Type]implements interface method

I've got Code Contracts working fine from inside Visual Studio 2010, but I can't get ccrewrite.exe to do anything useful from the command line. Here's a sample app: using System.Diagnostics.Contracts; public class Dummy { public static void Main(string[] args) { Contract.Requires(args.Length > 0); } } I then compile the code and run ccrewrite.exe on it: > csc /debug+ /D:CONTRACTS_FULL Dummy.cs > ccrewrite /o:RewrittenDummy.exe Dummy.exe elapsed time: 61ms There's no RewrittenDummy.exe file afterwards. I've tried loads of options, but nothing's making any difference. A few things I've noticed:

I'm wondering whether should I throw exceptions or call Contract.Requires<TException> For example: public static void Function(String str) { if (str == null) throw new ArgumentNullException("str", "Input string cannot be null."); // ... } vs public static void Function(String str) { Contract.Requires<ArgumentNullException>(str != null, "Input string cannot be null."); // ... } Since Contract.Requires<TException> doesn't require the CONTRACTS_FULL symbol I can keep it in my release builds as well. This is my consideration: Con: You can't call an overloaded version of the custom exception type