Breaking changes in Roslyn after .NET 9.0.100 through .NET 10.0.100

This document lists known breaking changes in Roslyn after .NET 9 general release (.NET SDK version 9.0.100) through .NET 10 general release (.NET SDK version 10.0.100).

Set state of enumerator object to "after" during disposal

Introduced in Visual Studio 2022 version 17.13

The state machine for enumerators incorrectly allowed resuming execution after the enumerator was disposed.
Now, MoveNext() on a disposed enumerator properly returns false without executing any more user code.

Imports System
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim enumerator = C.GetEnumerator()

        Console.Write(enumerator.MoveNext()) ' prints True
        Console.Write(enumerator.Current)    ' prints 1

        enumerator.Dispose()

        Console.Write(enumerator.MoveNext()) ' now prints False
    End Sub
End Module

Class C
    Public Shared Iterator Function GetEnumerator() As IEnumerator(Of Integer)
        Yield 1
        Console.Write("not executed after disposal")
        Yield 2
    End Function
End Class

Microsoft.CodeAnalysis.EmbeddedAttribute is validated on declaration

Introduced in Visual Studio 2022 version 17.13

The compiler now validates the shape of Microsoft.CodeAnalysis.EmbeddedAttribute when declared in source. Previously, the compiler would allow user-defined declarations of this attribute with any shape. We now validate that:

1. It must be Friend
2. It must be a Class
3. It must be NotInheritable
4. It must not be a Module
5. It must have a Public parameterless constructor
6. It must inherit from System.Attribute.
7. It must be allowed on any type declaration (Class, Structure, Interface, Enum, or Delegate)

Namespace Microsoft.CodeAnalysis

    ' Previously allowed. Now, BC37335
    Public Class EmbeddedAttribute
        Inherits Attribute
    End Class
End Namespace