Emacs: Replace company-lsp with company-capf.

company-lsp is no longer supported and will be deprecated soon.

init.d/programming/lsp.el

@@ -1,6 +1,6 @@
 ;;; lsp.el --- Language Server Protocol.             -*- lexical-binding: t; -*-
 
-;; Time-stamp: <2020-07-07T05:30:48+0200>
+;; Time-stamp: <2020-07-07T05:33:56+0200>
 
 ;;; Commentary:
 
@@ -20,7 +20,8 @@
              (lsp-auto-guess-root t)      ; Don't ask for project root.
              (lsp-eldoc-render-all t)
              (lsp-restart 'auto-restart)
-             (lsp-enable-semantic-highlighting t)) ; Needs clangd 11(?).
+             (lsp-enable-semantic-highlighting t) ; Needs clangd 11(?).
+             (lsp-prefer-capf t))
     :config (progn
               (setq lsp-clients-clangd-args '("--compile-commands-dir=build"))
               ;; Add “-clang-tidy” to clangd args if the version supports it.
@@ -30,7 +31,10 @@
               (put 'lsp-clients-clangd-args 'safe-local-variable #'consp))
     :bind ("C-c C-f" . lsp-execute-code-action)
     :hook ((c++-mode . lsp)
-           (c-mode . lsp)))
+           (c-mode . lsp)
+           ;; ↓ See <https://github.com/emacs-lsp/lsp-mode/issues/1736>. ↓
+           (lsp-managed-mode
+            . (lambda () (setq-local company-backends '(company-capf))))))
 
   ;; Eye-candy and flycheck support for lsp-mode.
   (use-package lsp-ui
@@ -51,13 +55,6 @@
     :hook ((lsp-mode . lsp-ui-mode)
            (lsp-ui-peek-mode . my/lsp-ws-toggle)))
 
-  ;; Completions with lsp-mode.
-  (use-package company-lsp
-    :demand t
-    :after (lsp-mode company)
-    :custom (company-lsp-cache-candidates 'auto)
-    :config (push 'company-lsp company-backends))
-
   ;; ivy interface to lsp-mode.
   (use-package lsp-ivy
     :demand t