Build and project bug fixes possibly related to Visual Studio 2017 compatibility

VisualRust.Build/Rustc.cs

@@ -373,6 +373,10 @@ public static void LogRustcMessage(RustcMessageJson msg, string rootPath, TaskLo
             // todo all other fields
             // todo mb help key word is code.explanation
 
+            // cargo build json messages don't always contain a message component
+            if (msg == null)
+                return;
+
             var type = msg.GetLevelAsEnum();
             var primarySpan = msg.GetPrimarySpan();
             var code = msg.GetErrorCodeAsString();

VisualRust.ProjectSystem.FileSystemMirroring/IO/MsBuildFileSystemWatcher.cs

@@ -13,6 +13,7 @@
 using System.IO.Abstractions;
 using NotifyFilters = System.IO.NotifyFilters;
 using IOException = System.IO.IOException;
+using Win32Exception = System.ComponentModel.Win32Exception;
 using ErrorEventArgs = System.IO.ErrorEventArgs;
 
 #if VS14
@@ -222,10 +223,14 @@ private static bool IsFileAllowed(string rootDirectory, string fullPath,
             shortRelativePath = null;
             if (fullPath.StartsWithIgnoreCase(rootDirectory)) {
                 relativePath = PathHelper.MakeRelative(rootDirectory, fullPath);
-                 try {
+                try
+                {
                     shortRelativePath = fileSystem.ToShortRelativePath(fullPath, rootDirectory);
                     return !string.IsNullOrEmpty(shortRelativePath) && filter.IsFileAllowed(relativePath, fileSystem.FileInfo.FromFileName(fullPath).Attributes);
-                } catch (IOException) { } catch (UnauthorizedAccessException) { } // File isn't allowed if it isn't accessible
+                }
+                catch (IOException) { }
+                catch (UnauthorizedAccessException) { } // File isn't allowed if it isn't accessible
+                catch (Win32Exception) { } // ToShortPath can throw a Win32Exception if the file doesn't exist anymore, which isn't exceptional
             }
             return false;
         }

VisualRust.ProjectSystem.FileSystemMirroring/Project/FileSystemMirroringProject.cs

@@ -137,6 +137,7 @@ private async Task ReevaluateLoadedConfiguredProjects(CancellationToken cancella
             foreach (var configuredProject in _unconfiguredProject.LoadedConfiguredProjects) {
                 try {
                     var jsproj = await access.GetProjectAsync(configuredProject, cancellationToken);
+                    jsproj.MarkDirty();
                     jsproj.ReevaluateIfNecessary();
                 } catch (Exception ex) {
                     System.Diagnostics.Debug.Fail("We were unable to mark a configuration as dirty" + ex.Message, ex.StackTrace);