This fixes bug #36801.
* lisp/progmodes/cc-langs.el (c-pre-lambda-tokens-re): Use c-make-keywords-re
rather than regexp-opt to make an optimised regexp out of a list of tokens.
(c-lang-defconst c-pre-lambda-tokens-re
;; Regexp matching any token in the list `c-pre-lambda-tokens'.
- t (regexp-opt (c-lang-const c-pre-lambda-tokens)))
+ t (c-make-keywords-re t (c-lang-const c-pre-lambda-tokens)))
(c-lang-defvar c-pre-lambda-tokens-re (c-lang-const c-pre-lambda-tokens-re))
\f
;;; Syntactic whitespace.