feat(emacs): Replace LSP-mode with eglot

LSP-mode in combination with the Rust language server does not really
work as RLS is extremely unstable.

This switches over to eglot, which automatically restarts RLS after
every crash. From initial testing it seems to be slightly less
annoying than the previous setup.

2 files changed, 15 insertions, 7 deletions

diff --git a/emacs.nix b/emacs.nix
index e5780812df2a..8700ac645424 100644
--- a/emacs.nix
+++ b/emacs.nix
@@ -1,5 +1,4 @@
 # Derivation for Emacs configured with the packages that I need:
-
 { pkgs }:
 
 let emacsWithPackages = with pkgs; (emacsPackagesNgGen emacs).emacsWithPackages;
@@ -58,6 +57,20 @@ nix-mode = with pkgs; emacsPackagesNg.melpaBuild {
   '';
 };
 
+# The default Rust language server mode is not really usable, install
+# `eglot` instead and hope for the best.
+eglot = with pkgs; emacsPackagesNg.melpaBuild rec {
+  pname = "eglot";
+  version = "0.8";
+
+  src = fetchFromGitHub {
+    owner  = "joaotavora";
+    repo   = "eglot";
+    rev    = version;
+    sha256 = "1avsry84sp3s2vr2iz9dphm579xgw8pqlwffl75gn5akykgazwdx";
+  };
+};
+
 in emacsWithPackages(epkgs:
   # Pinned packages (from unstable):
   (with pkgs; with lib; attrValues pinnedEmacs) ++
@@ -91,7 +104,6 @@ in emacsWithPackages(epkgs:
     haskell-mode
     ht
     idle-highlight-mode
-    intero
     kotlin-mode
     magit
     multi-term
@@ -116,5 +128,5 @@ in emacsWithPackages(epkgs:
   ]) ++
 
   # Custom packaged Emacs packages:
-  [ sly sly-company nix-mode pkgs.notmuch ]
+  [ sly sly-company nix-mode eglot pkgs.notmuch ]
 )
diff --git a/packages.nix b/packages.nix
index a0163eedc708..4c96ebb9e545 100644
--- a/packages.nix
+++ b/packages.nix
@@ -49,7 +49,6 @@ in {
       # Override various Emacs packages from unstable:
       pinnedEmacs = with unstable.emacsPackagesNg; {
         inherit
-          company-lsp
           counsel
           counsel-tramp
           exwm
@@ -57,9 +56,6 @@ in {
           ivy-gitlab
           ivy-hydra
           ivy-pass
-          lsp-mode
-          lsp-rust
-          lsp-ui
           markdown-mode
           markdown-toc
           swiper;