When an analyzer fails to load, log an error

Right now we just silently fail which isn't a good debugging experience.
Ideally these would be shown in the error list but this is good enough
when trying to track things down.

src/OmniSharp.MSBuild/ProjectManager.cs

@@ -366,6 +366,8 @@ private void AddProject(ProjectFileInfo projectFileInfo)
             var newSolution = _workspace.CurrentSolution.AddProject(projectInfo);
             _workspace.AddDocumentInclusionRuleForProject(projectInfo.Id, (filePath) => projectFileInfo.IsFileIncluded(filePath));
 
+            SubscribeToAnalyzerReferenceLoadFailures(projectInfo.AnalyzerReferences.Cast<AnalyzerFileReference>(), _logger);
+
             if (!_workspace.TryApplyChanges(newSolution))
             {
                 _logger.LogError($"Failed to add project to workspace: '{projectFileInfo.FilePath}'");
@@ -478,10 +480,22 @@ private void UpdateAnalyzerReferences(Project project, ProjectFileInfo projectFi
         {
             var analyzerFileReferences = projectFileInfo.ResolveAnalyzerReferencesForProject(_analyzerAssemblyLoader);
 
+            SubscribeToAnalyzerReferenceLoadFailures(analyzerFileReferences, _logger);
 
             _workspace.SetAnalyzerReferences(project.Id, analyzerFileReferences);
         }
 
+        private void SubscribeToAnalyzerReferenceLoadFailures(IEnumerable<AnalyzerFileReference> analyzerFileReferences, ILogger logger)
+        {
+            foreach (var analyzerFileReference in analyzerFileReferences)
+            {
+                analyzerFileReference.AnalyzerLoadFailed += (sender, e) =>
+                {
+                    logger.LogError($"Failure while loading the analyzer reference '{analyzerFileReference.Display}': {e.Message}");
+                };
+            }
+        }
+
         private void UpdateProjectProperties(Project project, ProjectFileInfo projectFileInfo)
         {
             if (projectFileInfo.DefaultNamespace != project.DefaultNamespace)