markdown-nested-imenu-heading-index = nil

See jrblevin/markdown-mode#578.

modules/lang/markdown/config.el

@@ -26,6 +26,10 @@ capture, the end position, and the output buffer.")
         markdown-gfm-additional-languages '("sh")
         markdown-make-gfm-checkboxes-buttons t
 
+        ;; HACK Due to jrblevin/markdown-mode#578, invoking `imenu' throws a
+        ;;      'wrong-type-argument consp nil' error if you use native-comp.
+        markdown-nested-imenu-heading-index (not (ignore-errors (native-comp-available-p)))
+
         ;; `+markdown-compile' offers support for many transpilers (see
         ;; `+markdown-compile-functions'), which it tries until one succeeds.
         markdown-command #'+markdown-compile