flycheck shows error messages when opening hh file

I'm not sure if this is the right place to ask this question, but no error message are shown by flycheck when cc file opened. I'm using doom-emacs, and emacs-ccls. I opened ccls project to give it a try, code completion works fine. The following errors are showing (with ccls/src/serializer.hh opened):

serialize… 4 9 warning #pragma once in main file (c/c++-clang) serializ… 8 10 error 'llvm/Support/Compiler.h' file not found (c/c++-clang) utils.hh 56 6 error no template named 'optional' in namespace 'std' (c/c++-clang) utils.hh 57 6 error no template named 'optional' in namespace 'std' (c/c++-clang) utils.hh 60 29 error no type named 'string_view' in namespace 'std' (c/c++-clang) utils.hh 60 51 error no type named 'string_view' in namespace 'std' (c/c++-clang) utils.hh 102 14 error no type named 'nullopt_t' in namespace 'std'; did you mean 'nullptr_t'? (c/c++-clang) utils.hh 119 17 error no template named 'optional' in namespace 'std' (c/c++-clang)

But no error is showing with ccls/src/serializer.cc opened.

my configuration:

config.el

(use-package! lsp-mode
  :commands (lsp-mode lsp-define-stdio-client))

(use-package! lsp-ui
  :hook (lsp-mode . lsp-ui-mode)
  :config
  (set-lookup-handlers! 'lsp-ui-mode
                        :definition #'lsp-ui-peek-find-definitions
                        :references #'lsp-ui-peek-find-references)
  (setq lsp-ui-doc-max-height 16
        lsp-ui-doc-max-width 50
        lsp-ui-doc-enable t
        lsp-ui-sideline-ignore-duplicate t))

(use-package! dap-mode
  :after lsp-mode
  :config
  (dap-mode t)
  (dap-ui-mode t))

(use-package! company-lsp
  :after lsp-mode
  :config
  (set-company-backend! 'lsp-mode 'company-lsp)
  (setq company-lsp-enable-recompletion t))

packages.el:

(when (package! lsp-mode)
  (package! lsp-ui)
  (package! company-lsp)
  (package! dap-mode))

init.el: :lang (cc +lsp), :tools lsp

emacs-lsp / emacs-ccls

flycheck shows error messages when opening hh file #66