Roslyn Compilation, 160 errors and process terminated due to NullReferenceException when a class with primary constructor implements INotifyPropertyChanged

[sherif-elmetainy]

Version Used:
C# 12, dotnet SDK version 8.0.100, MSBuild version 17.8.3+195e7f5a3 for .NET, Visual Studio Professional 2022 Version 17.8.3
Also occurs when using Rider version 2023.3.2

Steps to Reproduce:
1- Create a C# file with the following code and try to compile it.

using System.ComponentModel;

internal class MyClass(MyOtherClass otherClass, string key, int value) : INotifyPropertyChanged
{
    public string MyProperty { get; private set; } = GetValue(otherClass.MyProperty, key, value);
    private PropertyChangedEventHandler? _propertyChanged;


    private static string GetValue(string myProperty, string key, int value)
    {
        throw new NotImplementedException();
    }

    public event PropertyChangedEventHandler? PropertyChanged
    {
        add
        {
            lock (this)
            {
                if (_propertyChanged is null)
                {
                    otherClass.SomethingChanged += OnSomethingChanged;
                }
                _propertyChanged += value;

            }
        }
        remove
        {
            lock (this)
            {
                if (_propertyChanged is null)
                {
                    return;
                }
                _propertyChanged -= value;
                if (_propertyChanged is null)
                {
                    otherClass.SomethingChanged -= OnSomethingChanged;
                }
            }
        }
    }

    private void OnSomethingChanged(object? sender, EventArgs e)
    {
        throw new NotImplementedException();
    }
}

internal class MyOtherClass
{
    public event EventHandler? SomethingChanged;
    public string MyProperty { get; set; }
}

Expected Behavior:
The code should compile without error.

Actual Behavior:

• When building from the command line (dotnet build), the C# compiler produces 160 errors the crashes with error C:\Program Files\dotnet\sdk\8.0.100\Roslyn\Microsoft.CSharp.Core.targets(84,5): error : Process terminated. System.NullReferenceException: Object reference not set to an instance of an object. [D:\source\my\ConsoleApp1\ConsoleApp1\ConsoleApp1.csproj] (This is a partial log of the error which is very big, the entire error log is attached here).
• When building in Visual Studio I get C:\Program Files\Microsoft Visual Studio\2022\Professional\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error MSB6006: "csc.exe" exited with code -2146232797.

Moreover, when working with either Visual Studio or Rider, the C# analyzers and generators stop working (apparently because of the Roslyn process crashing). While this may not be apparent in my sample reproduction, it occurs in my actual project, but I kept the reproduction to minimum and excluded irrelevant code.

This seems to be similar to #50198, however the old issue is resolved (may be this is a regression?) and old one was related to records and not primary constructors.

Workaround:

Using a normal constructor instead of a primary constructor with that class fixed the issue and allowed me to continue my work.

[jhinder]

The repro can be simplified.

• The event must be an interface implementation.
• One of the event accessors needs to reference a field from the primary constructor, but it can be of any type.
• The mere reference of the constructor parameter is enough to trigger the error.

using System;

interface I
{
    event EventHandler E;
}

class C(int i) : I
{
    public event EventHandler E
    {
        add { i }
        remove { }
    }
}

https://sharplab.io/#v2:EYLgtghglgdgPgAQEwEYCwAoTsAuBTAJwDMIBjPAAgElMBvTCxivANzxhwoFE2OAJCDAAmAG0LcA3JgC+mTMgoBhABS4KUAJQUQ1OgyYIAzM16ce7HAOFiC3fY3oYmzihCFCKtdRVlOXjAjwwAHs2Tx97CIxpIA=

In the cases where it doesn't throw an exception, it fails this assertion here:

roslyn/src/Compilers/CSharp/Portable/Symbols/Source/SourceEventAccessorSymbol.cs

Line 193 in 182e829

Debug.Assert(!_lazyParameters.IsDefault);

[nvmkpk]

This also happens in MAUI and WPF when implementing ICommand interface