diff --git a/test/lisp/progmodes/flymake-tests.el b/test/lisp/progmodes/flymake-tests.el
index 0793b2bfdab..ced7b5aaced 100644
--- a/test/lisp/progmodes/flymake-tests.el
+++ b/test/lisp/progmodes/flymake-tests.el
@@ -145,11 +145,6 @@ SEVERITY-PREDICATE is used to setup
   (string-match "[Cc]lang version "
                 (shell-command-to-string "gcc --version")))
 
-(defun flymake-tests--gcc-is-clang ()
-  "Whether the `gcc' command actually runs the Clang compiler."
-  (string-match "[Cc]lang version "
-                (shell-command-to-string "gcc --version")))
-
 (ert-deftest different-diagnostic-types ()
   "Test GCC warning via function predicate."
   (skip-unless (and (executable-find "gcc")