lang/haskell: remove intero support

The package was deprecated and abandoned upstream since November 2019.

Closes #2121

modules/lang/haskell/+intero.el

@@ -1,30 +0,0 @@
-;;; lang/haskell/+intero.el -*- lexical-binding: t; -*-
-;;;###if (featurep! +intero)
-
-(use-package! intero
-  :commands intero-mode
-  :hook (haskell-mode-local-vars . +haskell-init-intero-h)
-  :config
-  (defun +haskell-init-intero-h ()
-    "Initializes `intero-mode' in haskell-mode, unless stack isn't installed.
-This is necessary because `intero-mode' doesn't do its own error checks."
-    (when (derived-mode-p 'haskell-mode)
-      (if (executable-find "stack")
-          (intero-mode +1)
-        (message "Couldn't find stack. Refusing to enable intero-mode."))))
-
-  (setq haskell-compile-cabal-build-command "stack build --fast")
-  (set-lookup-handlers! 'intero-mode :definition #'intero-goto-definition)
-  (set-company-backend! 'intero-mode 'intero-company)
-  (when (featurep! :checkers syntax)
-    (flycheck-add-next-checker 'intero '(warning . haskell-hlint)))
-
-  (when (featurep 'evil)
-    (add-hook 'intero-mode-hook #'evil-normalize-keymaps))
-  (map! :localleader
-        :map intero-mode-map
-        "t" #'intero-type-at
-        "i" #'intero-info
-        "l" #'intero-repl-load
-        "e" #'intero-repl-eval-region
-        "a" #'intero-apply-suggestions))

modules/lang/haskell/README.org

@@ -19,8 +19,8 @@
 - [[#troubleshooting][Troubleshooting]]
 
 * Description
-This module adds [[https://www.haskell.org/][Haskell]] support, powered by either [[https://github.com/jyp/dante][dante]] (the default), LSP
-(haskell-language-server or ghcide) or [[https://haskell-lang.org/intero][intero]].
+This module adds [[https://www.haskell.org/][Haskell]] support, powered by either [[https://github.com/jyp/dante][dante]] (the default) or LSP
+(haskell-language-server or ghcide).
 
 + Code completion (~company-ghc~)
 + Look up documentation (~hoogle~)
@@ -45,8 +45,6 @@ Here are a few resources I've found indispensable in my Haskell adventures:
 + =+ghcide= Enables LSP support with ghcide (requires the ~:tools lsp~ module).
 + =+lsp= Enables LSP support with haskell-ide-engine (requires the ~:tools lsp~
   module).
-+ =+intero= (Deprecated) Enables intero; a comprehensive, stack-based
-  development environment for Haskell.
 
 ** Plugins
 + [[https://github.com/haskell/haskell-mode][haskell-mode]]
@@ -55,16 +53,13 @@ Here are a few resources I've found indispensable in my Haskell adventures:
   + [[https://github.com/jyp/attrap][attrap]]
 + =+lsp=
   + [[https://github.com/emacs-lsp/lsp-haskell][lsp-haskell]]
-+ =+intero=
-  + [[https://github.com/chrisdone/intero][intero]] =DEPRECATED=
 
 * Prerequisites
-Depending on whether you use Intero, Dante or LSP, your dependencies will
-differ:
+Depending on whether you use Dante, haskell-language-server or ghcide, your
+dependencies will differ:
 
 + Dante users need =cabal=, =ghc= and =ghc-mod=
-+ LSP users need the =haskell-ide-engine= LSP server
-+ Intero and LSP users need =stack=
++ LSP users need the =haskell-ide-engine= LSP server OR =ghcide=
 + All users will need the =hoogle= package
 
 ** Cabal
@@ -111,7 +106,7 @@ yay -S haskell-ide-engine-git
 See https://github.com/digital-asset/ghcide for install instructions.
 
 ** Stack
-To use Intero or LSP, you need =stack=:
+To use LSP, you need =stack=:
 
 *** MacOS
 #+BEGIN_SRC sh

modules/lang/haskell/autoload.el

@@ -4,12 +4,9 @@
 (defun +haskell/open-repl (&optional arg)
   "Opens a Haskell REPL."
   (interactive "P")
-  (if-let*
-      ((window
-        (display-buffer
-         (if (featurep! +intero)
-             (intero-repl-buffer arg)
-           (haskell-session-interactive-buffer (haskell-session))))))
+  (if-let (window
+           (display-buffer
+            (haskell-session-interactive-buffer (haskell-session))))
       (window-buffer window)
     (error "Failed to display Haskell REPL")))
 

modules/lang/haskell/config.el

@@ -35,7 +35,6 @@
 
   (map! :localleader
         :map haskell-mode-map
-        ;; this is set to use cabal for dante users and stack for intero users:
         "b" #'haskell-process-cabal-build
         "c" #'haskell-cabal-visit-file
         "h" #'haskell-hide-toggle
@@ -45,8 +44,7 @@
 ;;
 ;;; Backends
 
-(cond ((featurep! +intero) (load! "+intero")) ; DEPRECATED
-      ((featurep! +dante)  (load! "+dante"))
+(cond ((featurep! +dante)  (load! "+dante"))
       ((or (featurep! +lsp)
            (featurep! +ghcide))
        (load! "+lsp")))

modules/lang/haskell/doctor.el

@@ -7,12 +7,6 @@
 
 (when (featurep! +dante)
   (unless (executable-find "cabal")
-    (warn! "Couldn't find cabal, haskell-mode may have issues")))
-
-(when (featurep! +intero)
-  (unless (executable-find "stack")
-    (warn! "Couldn't find stack. Intero will not work")))
-
-(when (or (featurep! +dante) (featurep! +intero))
+    (warn! "Couldn't find cabal, haskell-mode may have issues"))
   (unless (executable-find "hlint")
     (warn! "Couldn't find hlint. Flycheck may have issues in haskell-mode")))

modules/lang/haskell/packages.el

@@ -9,6 +9,3 @@
 (when (or (featurep! +lsp)
           (featurep! +ghcide))
   (package! lsp-haskell :pin "582fa27c88"))
-;; DEPRECATED
-(when (featurep! +intero)
-  (package! intero :pin "fdb0550a2d"))