From 6742695f53c96044f8ae06b6c86d13c0729be685 Mon Sep 17 00:00:00 2001
From: Daniel Borchmann <daniel@algebra20.de>
Date: Sat, 28 Nov 2020 08:50:47 +0100
Subject: [PATCH] Enable flycheck mode in Emacs Lisp only when buffer has a
 file

Flycheck used to be activated unconditionally, resulting in annoying warnings
when evaluating Lisp expressions in the minibuffer with `pp-eval-expression`,
and in the scratch buffer.
---
 init.el               | 3 ++-
 site-lisp/db-utils.el | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/init.el b/init.el
index 1fc4596..32dac21 100644
--- a/init.el
+++ b/init.el
@@ -593,6 +593,7 @@
              db/text-to-hex
              conditionally-enable-lispy
              turn-on-lispy-when-available
+             turn-on-flycheck-when-file
              db/sort-nsm-permanent-settings
              endless/colorize-compilation
              db/turn-off-local-electric-pair-mode
@@ -2587,7 +2588,7 @@ With given ARG, display files in `db/important-document-path’."
 (use-package elisp-mode
   :config (progn
             (add-hook 'emacs-lisp-mode-hook 'turn-on-lispy-when-available)
-            (add-hook 'emacs-lisp-mode-hook 'flycheck-mode)))
+            (add-hook 'emacs-lisp-mode-hook 'turn-on-flycheck-when-file)))
 
 (use-package geiser
   :commands (geiser-mode))
diff --git a/site-lisp/db-utils.el b/site-lisp/db-utils.el
index 58d6bf2..099c006 100644
--- a/site-lisp/db-utils.el
+++ b/site-lisp/db-utils.el
@@ -257,6 +257,11 @@ Will print a warning in case of failure."
     (require 'lispy)
     (lispy-mode)))
 
+(defun turn-on-flycheck-when-file ()
+  "Turn on `flycheck-mode' when buffer is associated with a file."
+  (when buffer-file-name
+    (flycheck-mode +1)))
+
 (defun db/sort-nsm-permanent-settings ()
   "Sort values in `nsm-permanent-host-settings’."
   (setq nsm-permanent-host-settings