dotnet-core/release-notes/3.0/preview/api-diff/preview6/3.0-preview6_System.Runtime.CompilerServices.md

System.Runtime.CompilerServices

 namespace System.Runtime.CompilerServices {
     public sealed class ConditionalWeakTable<TKey, TValue> : IEnumerable, IEnumerable<KeyValuePair<TKey, TValue>> where TKey : class where TValue : class {
-        ~ConditionalWeakTable();

     }
     public sealed class SwitchExpressionException : InvalidOperationException {
+        public override string Message { get; }
     }
 }