change_return_value.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;

namespace testingconsole
{
  class Program
  {
    static void Main(string[] args)
    {
      while (true)
      {
        Thread.Sleep(500);
        Test();
      }
    }

    static void Test()
    {
      Console.WriteLine("Hello World!");

      var p = new Program();
      Console.WriteLine(p.OtherTest());
    }

    // comment out this function and comment in the one below to see the error:
    // Unhandled exception. System.InvalidCastException: Unable to cast object of type 'System.Collections.Generic.Dictionary`2[System.Int32,System.String]' to type 'System.Int32'.
    //  at testingconsole.Program.OtherTest()
    //  at testingconsole.Program.Test() in /Users/johnfn/code/testingconsole/Program.cs:line 24
    //  at testingconsole.Program.Main(String[] args) in /Users/johnfn/code/testingconsole/Program.cs:line 15

   
    public int OtherTest() {
      return 5;
    }

    // public Dictionary<int, string> OtherTest() {
    //   return new Dictionary<int, string>();
    // }
  }
}

new_return_value.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Threading;

namespace testingconsole
{
  class Program
  {
    static void Main(string[] args)
    {
      while (true)
      {
        Thread.Sleep(500);
        Test();
      }
    }

    static void Test()
    {
      Console.WriteLine("Hello World.");
      // Console.WriteLine("Hello World 2.");

      var p = new Program();

      OtherTest();
    }

    // Comment out this function, and comment in the second "Console.WriteLine" in Test() and the function below
    // to cause the bug:

    public static void OtherTest() {
      return;
    }

    // public static Dictionary<int, string> OtherTest() {
    //   return new Dictionary<int, string>();
    // }
  }
}


// Unhandled exception. IlCompilationException: System.AggregateException: Instruction compilation failed: 10: pop  (Cannot Pop elements from an empty ImmutableStack)
//   ---> System.InvalidOperationException: Cannot Pop elements from an empty ImmutableStack
//   at LiveSharp.Runtime.Infrastructure.ImmutableStack`1.Pop()
// at LiveSharp.Runtime.IL.InstructionContext.PopStack()
// at LiveSharp.Runtime.IL.IlExpressionCompilerHandlers.Pop(InstructionContext ctx)

reducible.cs

using System;
using System.IO;
using System.Threading;

namespace testingconsole
{
  class Program
  {
    static void Main(string[] args)
    {
      while (true)
      {
        Thread.Sleep(500);
        Test();
      }
    }

    static void Test()
    {
      // uncomment this line to see the error
      // var projectDirectory = Directory.GetParent(Environment.CurrentDirectory).Parent?.Parent?.FullName;

      Console.WriteLine("Hello World!");
    }
  }
}