Fix CA errors.

Author: grokys

src/GitHub.App/Services/PullRequestEditorService.cs

@@ -420,8 +420,7 @@ bool FocusExistingDiffViewer(
                         leftBufferInfo.Session.PullRequest.Number == session.PullRequest.Number &&
                         leftBufferInfo.CommitSha == mergeBase)
                     {
-                        windowFrame.Show();
-                        return true;
+                        return ErrorHandler.Succeeded(windowFrame.Show());
                     }
                 }
             }
@@ -563,8 +562,13 @@ static string GetAbsolutePath(IPullRequestSession session, IPullRequestSessionFi
         static IDifferenceViewer GetDiffViewer(IVsWindowFrame frame)
         {
             object docView;
-            frame.GetProperty((int)__VSFPROPID.VSFPROPID_DocView, out docView);
-            return (docView as IVsDifferenceCodeWindow)?.DifferenceViewer;
+
+            if (ErrorHandler.Succeeded(frame.GetProperty((int)__VSFPROPID.VSFPROPID_DocView, out docView)))
+            {
+                return (docView as IVsDifferenceCodeWindow)?.DifferenceViewer;
+            }
+
+            return null;
         }
 
         static IDisposable OpenInProvisionalTab()

src/GitHub.App/Services/PullRequestService.cs

@@ -17,6 +17,7 @@
 using LibGit2Sharp;
 using GitHub.Logging;
 using GitHub.Extensions;
+using static System.FormattableString;
 
 namespace GitHub.Services
 {
@@ -680,7 +681,7 @@ static string CalculateTempFileName(string relativePath, string commitSha, Encod
             var key = relativeDir + '|' + encoding.WebName;
             var relativePathHash = key.GetSha256Hash();
             var tempDir = Path.Combine(Path.GetTempPath(), "GitHubVisualStudio", "FileContents", relativePathHash);
-            var tempFileName = $"{Path.GetFileNameWithoutExtension(relativePath)}@{commitSha}{Path.GetExtension(relativePath)}";
+            var tempFileName = Invariant($"{Path.GetFileNameWithoutExtension(relativePath)}@{commitSha}{Path.GetExtension(relativePath)}");
             return Path.Combine(tempDir, tempFileName);
         }