codeql/csharp/ql/test/library-tests/cil/dataflow/DataFlow.cs_

// Generate DataFlow.dll: `csc /o /target:library DataFlow.cs_ /out:DataFlow.dll`

using System;

namespace Dataflow
{
    public class NullMethods
    {
        public object ReturnsNull() => null;

        public object ReturnsNull2()
        {
            var x = ReturnsNull();
            return x;
        }

        // Does not necessarily return null because of virtual method call.
        public object NotReturnsNull() => VirtualReturnsNull();

        public object ReturnsNullIndirect() => ReturnsNull();

        public virtual object VirtualReturnsNull() => null;

        public object NullProperty { get => null; }

        public virtual object VirtualNullProperty { get => null; }
    }

    public class NonNullMethods
    {
        public object ReturnsNonNull() => new object();

        public object ReturnsNonNull2()
        {
            var x = ReturnsNonNull();
            return x;
        }

        public object ReturnsNonNullIndirect() => ReturnsNonNull();

        public object NonNullProperty { get => 1; }

        public string NonNullProperty2 { get => "not null"; }

        public virtual object VirtualNonNull { get => "not null"; }

        public bool cond = false;

        public string MaybeNull()
        {
            if (cond)
                return null;
            else
                return "not null";
        }

        public string MaybeNull2()
        {
            return cond ? null : "not null";
        }

        public virtual object VirtualNonNullProperty { get => "non null"; }
    }

    public class ThrowingMethods
    {
        public static object AlwaysThrows() => throw new InvalidOperationException();

        public object AlwaysThrowsIndirect() => AlwaysThrows();

        public virtual object VirtualThrows() => throw new Exception();

        public object ThrowProperty { get => throw new Exception(); }
        public virtual object VirtualThrowProperty { get => throw new Exception(); }

    }

    public class DataFlow
    {
        public object Taint1(object x) => x;

        public object Taint2(object x) => Taint5(x);

        public string Taint3(string s)
        {
            var x = s;
            Console.WriteLine(s);
            return x;
        }

        public object Taint5(object x) => Taint6(x);

        private object Taint6(object x) => x;
    }

    public class TaintFlow
    {
        public string Taint1(string a, string b) => a + b;

        public int Taint2(int a, int b) => a + b;

        public int Taint3(int a) => -a;

        public string TaintIndirect(string a, string b) => Taint1(a, b);
    }

    public class Properties
    {
        public int TrivialProperty1 { get; set; }

        int field;

        public int TrivialProperty2
        {
            get => field;
            set { field = value; }
        }
    }

    public class ThisAssemblyIsNotAStub
    {
        public void F()
        {
            // Ensure that the assembly isn't tagged as a stub
            // Need to bump the average instruction count.
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
            Console.WriteLine("This is not a stub assembly");
        }
    }
}