Add Elixir linter for dialyxir (#1257)

* Add Elixir linter for dialyxir

* Update doc/ale.txt with dialyxir

* Keep elixir tools alphabetically ordered in README

* Add a missing entry for dialyxir to the main documentation file.

4 files changed, 52 insertions, 2 deletions

diff --git a/README.md b/README.md
index 29095df3..c42f4bfa 100644
--- a/README.md
+++ b/README.md
@@ -94,7 +94,7 @@ formatting.
 | Dafny | [dafny](https://rise4fun.com/Dafny) !! |
 | Dart | [dartanalyzer](https://github.com/dart-lang/sdk/tree/master/pkg/analyzer_cli) !!, [language_server](https://github.com/natebosch/dart_language_server) |
 | Dockerfile | [hadolint](https://github.com/lukasmartinelli/hadolint) |
-| Elixir | [credo](https://github.com/rrrene/credo), [dogma](https://github.com/lpil/dogma) !! |
+| Elixir | [credo](https://github.com/rrrene/credo), [dialyxir](https://github.com/jeremyjh/dialyxir), [dogma](https://github.com/lpil/dogma) !!|
 | Elm | [elm-format](https://github.com/avh4/elm-format), [elm-make](https://github.com/elm-lang/elm-make) |
 | Erb | [erb](https://github.com/jeremyevans/erubi), [erubis](https://github.com/kwatch/erubis) |
 | Erlang | [erlc](http://erlang.org/doc/man/erlc.html), [SyntaxErl](https://github.com/ten0s/syntaxerl) |
diff --git a/ale_linters/elixir/dialyxir.vim b/ale_linters/elixir/dialyxir.vim
new file mode 100644
index 00000000..5ef3a047
--- /dev/null
+++ b/ale_linters/elixir/dialyxir.vim
@@ -0,0 +1,34 @@
+" Author: Fran C. - https://github.com/franciscoj
+" Description: Add dialyzer support for elixir through dialyxir
+" https://github.com/jeremyjh/dialyxir
+
+function! ale_linters#elixir#dialyxir#Handle(buffer, lines) abort
+    " Matches patterns line the following:
+    "
+    " lib/filename.ex:19: Function fname/1 has no local return
+    let l:pattern = '\v(.+):(\d+): (.+)$'
+    let l:output = []
+    let l:type = 'W'
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        if bufname(a:buffer) == l:match[1]
+            call add(l:output, {
+            \   'bufnr': a:buffer,
+            \   'lnum': l:match[2] + 0,
+            \   'col': 0,
+            \   'type': l:type,
+            \   'text': l:match[3],
+            \})
+        endif
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('elixir', {
+\   'name': 'dialyxir',
+\   'executable': 'mix',
+\   'command': 'mix dialyzer',
+\   'callback': 'ale_linters#elixir#dialyxir#Handle',
+\})
+
diff --git a/doc/ale-elixir.txt b/doc/ale-elixir.txt
index a5318c0f..b7d4922e 100644
--- a/doc/ale-elixir.txt
+++ b/doc/ale-elixir.txt
@@ -14,4 +14,19 @@ g:ale_elixir_mix_options                             *g:ale_elixir_mix_options*
   This variable can be changed to specify the mix executable.
 
 ===============================================================================
+dialyxir                                                  *ale-elixir-dialyxir*
+
+Dialyzer, a DIscrepancy AnaLYZer for ERlang programs.
+http://erlang.org/doc/man/dialyzer.html
+
+It can be used with elixir through dialyxir
+https://github.com/jeremyjh/dialyxir
+
+Options for dialyzer are not configurable by ale, but they are instead
+configured on your project's `mix.exs`.
+
+See https://github.com/jeremyjh/dialyxir#with-explaining-stuff for more
+information.
+
+===============================================================================
   vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:
diff --git a/doc/ale.txt b/doc/ale.txt
index b99c800c..47765685 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -57,6 +57,7 @@ CONTENTS                                                         *ale-contents*
       hadolint............................|ale-dockerfile-hadolint|
     elixir................................|ale-elixir-options|
       mix.................................|ale-elixir-mix|
+      dialyxir............................|ale-elixir-dialyxir|
     elm...................................|ale-elm-options|
       elm-format..........................|ale-elm-elm-format|
       elm-make............................|ale-elm-elm-make|
@@ -301,7 +302,7 @@ Notes:
 * Dafny: `dafny`!!
 * Dart: `dartanalyzer`!!, `language_server`
 * Dockerfile: `hadolint`
-* Elixir: `credo`, `dogma`!!
+* Elixir: `credo`, `dialyxir`, `dogma`!!
 * Elm: `elm-format, elm-make`
 * Erb: `erb`, `erubis`
 * Erlang: `erlc`, `SyntaxErl`