Add telemetry

src/Features/Core/Portable/EditAndContinue/EncDebuggingSessionInfo.cs

@@ -4,10 +4,11 @@
 
 namespace Microsoft.CodeAnalysis.EditAndContinue
 {
-    internal class EncDebuggingSessionInfo
+    internal sealed class EncDebuggingSessionInfo
     {
         public readonly List<EncEditSessionInfo> EditSessions = new List<EncEditSessionInfo>();
-        public int EmptyEditSessions;
+        public int EmptyEditSessions { get; private set; }
+        public bool ReadOnlyEditAttemptedProjectNotBuiltOrLoaded { get; private set; }
 
         internal void EndEditSession(EncEditSessionInfo encEditSessionInfo)
         {
@@ -20,5 +21,10 @@ internal void EndEditSession(EncEditSessionInfo encEditSessionInfo)
                 EditSessions.Add(encEditSessionInfo);
             }
         }
+
+        internal void LogReadOnlyEditAttemptedProjectNotBuiltOrLoaded()
+        {
+            ReadOnlyEditAttemptedProjectNotBuiltOrLoaded = true;
+        }
     }
 }

src/VisualStudio/Core/Def/Implementation/EditAndContinue/DebugLogMessage.cs

@@ -17,6 +17,7 @@ internal static class DebugLogMessage
 
         private const string SessionCount = nameof(SessionCount);
         private const string EmptySessionCount = nameof(EmptySessionCount);
+        private const string ReadOnlyEditAttemptedProjectNotBuiltOrLoaded = nameof(ReadOnlyEditAttemptedProjectNotBuiltOrLoaded);
 
         private const string HadCompilationErrors = nameof(HadCompilationErrors);
         private const string HadRudeEdits = nameof(HadRudeEdits);
@@ -61,6 +62,7 @@ private static void CreateSessionKeyValue(Dictionary<string, object> map, int se
             map[SessionId] = sessionId;
             map[SessionCount] = session.EditSessions.Count;
             map[EmptySessionCount] = session.EmptyEditSessions;
+            map[ReadOnlyEditAttemptedProjectNotBuiltOrLoaded] = session.ReadOnlyEditAttemptedProjectNotBuiltOrLoaded;
         }
 
         private static void CreateSessionEditKeyValue(Dictionary<string, object> map, int sessionId, int editSessionId, EncEditSessionInfo editSession)

src/VisualStudio/Core/Def/Implementation/EditAndContinue/VsENCRebuildableProjectImpl.cs

@@ -175,6 +175,8 @@ internal bool OnEdit(DocumentId documentId)
                                       Environment.NewLine +
                                       "'Lightweight solution load' is enabled for the current solution. " +
                                       "Disable it to ensure that all projects are loaded when debugging starts.";
+
+                            s_encDebuggingSessionInfo?.LogReadOnlyEditAttemptedProjectNotBuiltOrLoaded();
                         }
                         else
                         {