Snippet of my Spacemacs config showing Merlin usage

spmcs.el

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(evil-want-Y-yank-to-eol nil)
 '(merlin-command (quote opam))
 '(merlin-completion-with-doc t)
 '(package-selected-packages
   (quote
    (intero flycheck hlint-refactor hindent haskell-snippets company-ghci company-ghc ghc haskell-mode company-cabal cmm-mode ibuffer-projectile org-projectile org-present org-pomodoro alert log4e gntp org-download htmlize gnuplot utop tuareg caml ocp-indent merlin zonokai-theme zen-and-art-theme underwater-theme ujelly-theme twilight-theme twilight-bright-theme twilight-anti-bright-theme tronesque-theme toxi-theme tao-theme tangotango-theme tango-plus-theme tango-2-theme sunny-day-theme sublime-themes subatomic256-theme subatomic-theme spacegray-theme soothe-theme solarized-theme soft-stone-theme soft-morning-theme soft-charcoal-theme smyx-theme smeargle seti-theme reverse-theme railscasts-theme purple-haze-theme professional-theme planet-theme phoenix-dark-pink-theme phoenix-dark-mono-theme pastels-on-dark-theme orgit organic-green-theme omtose-phellack-theme oldlace-theme occidental-theme obsidian-theme noctilux-theme niflheim-theme naquadah-theme mustang-theme monokai-theme monochrome-theme molokai-theme moe-theme mmm-mode minimal-theme material-theme markdown-toc markdown-mode majapahit-theme magit-gitflow madhat2r-theme lush-theme light-soap-theme jbeans-theme jazz-theme ir-black-theme inkpot-theme heroku-theme hemisu-theme hc-zenburn-theme gruvbox-theme gruber-darker-theme grandshell-theme gotham-theme gitignore-mode gitconfig-mode gitattributes-mode git-timemachine git-messenger git-link git-gutter-fringe+ git-gutter-fringe fringe-helper git-gutter+ git-gutter gh-md gandalf-theme fuzzy flyspell-correct-ivy flyspell-correct flatui-theme flatland-theme firebelly-theme farmhouse-theme evil-magit magit magit-popup git-commit with-editor espresso-theme dracula-theme django-theme diff-hl darktooth-theme autothemer darkokai-theme darkmine-theme darkburn-theme dakrone-theme cyberpunk-theme company-statistics company color-theme-sanityinc-tomorrow color-theme-sanityinc-solarized clues-theme cherry-blossom-theme busybee-theme bubbleberry-theme birds-of-paradise-plus-theme badwolf-theme auto-yasnippet yasnippet auto-dictionary apropospriate-theme anti-zenburn-theme ample-zen-theme ample-theme alect-themes afternoon-theme ac-ispell auto-complete ws-butler winum which-key wgrep volatile-highlights vi-tilde-fringe uuidgen use-package toc-org spaceline powerline smex restart-emacs request rainbow-delimiters popwin persp-mode pcre2el paradox spinner org-plus-contrib org-bullets open-junk-file neotree move-text macrostep lorem-ipsum linum-relative link-hint ivy-hydra info+ indent-guide hydra hungry-delete hl-todo highlight-parentheses highlight-numbers parent-mode highlight-indentation hide-comnt help-fns+ helm-make helm helm-core google-translate golden-ratio flx-ido flx fill-column-indicator fancy-battery eyebrowse expand-region exec-path-from-shell evil-visualstar evil-visual-mark-mode evil-unimpaired evil-tutor evil-surround evil-search-highlight-persist evil-numbers evil-nerd-commenter evil-mc evil-matchit evil-lisp-state smartparens evil-indent-plus evil-iedit-state iedit evil-exchange evil-escape evil-ediff evil-args evil-anzu anzu evil goto-chg undo-tree eval-sexp-fu highlight elisp-slime-nav dumb-jump popup f s diminish define-word counsel-projectile projectile pkg-info epl counsel swiper ivy column-enforce-mode clean-aindent-mode bind-map bind-key auto-highlight-symbol auto-compile packed dash async aggressive-indent adaptive-wrap ace-window ace-link avy))))