*** /tmp/ediffuS9ebt	2021-02-11 16:14:54.793873579 +0100
--- /net/ford/albinus/src/tramp/lisp/tramp-integration.el	2021-02-11 16:10:01.276681568 +0100
***************
*** 261,266 ****
--- 261,294 ----
  		  (delete (info-lookup->mode-cache 'symbol ',mode)
  			  (info-lookup->topic-cache 'symbol))))))))

+ ;; Compilation processes use `accept-process-output' such a way that
+ ;; Tramp's parallel `accept-process-output' blocks.  See last part of
+ ;; Bug#45518.  So we forbid them to run in parallel.  There must be a
+ ;; better solution, though.
+ (with-eval-after-load 'compile
+   (add-hook 'compilation-start-hook
+ 	    #'tramp-compile-advice-add)
+   (add-hook 'compilation-finish-functions
+ 	    #'tramp-compile-advice-remove)
+   (add-hook 'tramp-integration-unload-hook
+ 	    (lambda ()
+ 	      (remove-hook 'compilation-start-hook
+ 			   #'tramp-compile-advice-add)
+ 	      (remove-hook 'compilation-finish-functions
+ 			   #'tramp-compile-advice-remove))))
+
+ (defun tramp-compile-advice-add (proc)
+   "Don't allow remote file operations while compiling."
+   (with-current-buffer (process-buffer proc)
+     (when (file-remote-p default-directory)
+       (advice-add 'ignore :override 'compile-goto-error))))
+
+ (defun tramp-compile-advice-remove (buffer _message)
+   "Reenable remote file operations."
+   (with-current-buffer buffer
+     (when (file-remote-p  default-directory)
+       (advice-remove 'ignore 'compile-goto-error))))
+
  ;;; Default connection-local variables for Tramp:
  ;; `connection-local-set-profile-variables' and
  ;; `connection-local-set-profiles' exists since Emacs 26.1.