Font-locking fails when `font-lock-maximum-decoration` is an alist

[zk-phi]

Conforming Bugs

Please tell us below:

• [x] basic information
  • OS name: [Mac OS]
  • Versions: Emacs [26.1], Nim compiler [1.0.4]
• [x] Are you using latest version of nim-mode? [YES]
• [x] Are there message related to nim-mode in *Messages* buffer? [YES]
• [x] Did you read README.md? [YES]
• [x] Is your problem related to nimsuggest-mode? (company-mode, flycheck, or el-doc) [NO]
  • [x] Did you try nim-mode without nimsugggest-mode? What happened? (Comment out nimsuggest-mode's config please)
  • [nimsuggest-mode is not installed but the error occurs]

And describe your problem:

When font-lock-maximum-decoration is an alist (((cperl-mode . 1) (t . t)) in my environment), nim-mode fails to font-lock the buffer with invalid-function error (seen in the *Messages* buffer).

I also tried to call font-lock-fontify-region manually and got following backtrace:

Debugger entered--Lisp error: (invalid-function ("\\(?:^\\|;\\) *\\_<\\(?:\\(?:converter\\|func\\|iterator\\|m\\(?:acro\\|ethod\\)\\|proc\\|template\\)\\)\\_> +\\(\\(?:[[:alpha:]]\\(?:_\\|[[:alnum:]]\\)*\\|`[]-_!$-&*-/<-@[|~[:alnum:]]+?`\\) *\\(\\*\\)?\\)" (1 (if (match-string 2) 'nim-font-lock-export-face font-lock-function-name-face) keep t)))
("\\(?:^\\|;\\) *\\_<\\(?:\\(?:converter\\|func\\|iterator\\|m\\(?:acro\\|ethod\\)\\|proc\\|template\\)\\)\\_> +\\(\\(?:[[:alpha:]]\\(?:_\\|[[:alnum:]]\\)*\\|`[]-_!$-&*-/<-@[|~[:alnum:]]+?`\\) *\\(\\*\\)?\\)" (1 (if (match-string 2) 'nim-font-lock-export-face font-lock-function-name-face) keep t))(184)
font-lock-fontify-keywords-region(1 184 nil)
font-lock-default-fontify-region(1 184 nil)
font-lock-fontify-region(1 184)
eval((font-lock-fontify-region (point-min) (point-max)) nil)

This does not occur when font-lock-maximum-decoration is t, which is the default value.

[krux02]

Thanks a lot for the feedback. I think this should be easy to fix.