Fix #1166 - Add an option for the rls toolchain

ale_linters/rust/rls.vim

@@ -2,6 +2,7 @@
 " Description: A language server for Rust
 
 call ale#Set('rust_rls_executable', 'rls')
+call ale#Set('rust_rls_toolchain', 'nightly')
 
 function! ale_linters#rust#rls#GetExecutable(buffer) abort
     return ale#Var(a:buffer, 'rust_rls_executable')
@@ -9,8 +10,10 @@ endfunction
 
 function! ale_linters#rust#rls#GetCommand(buffer) abort
     let l:executable = ale_linters#rust#rls#GetExecutable(a:buffer)
+    let l:toolchain = ale#Var(a:buffer, 'rust_rls_toolchain')
 
-    return ale#Escape(l:executable) . ' +nightly'
+    return ale#Escape(l:executable)
+    \   . ' +' . ale#Escape(l:toolchain)
 endfunction
 
 function! ale_linters#rust#rls#GetLanguage(buffer) abort

doc/ale-rust.txt

@@ -70,6 +70,17 @@ g:ale_rust_rls_executable                           *g:ale_rust_rls_executable*
   This variable can be modified to change the executable path for `rls`.
 
 
+g:ale_rust_rls_toolchain                             *g:ale_rust_rls_toolchain*
+                                                     *b:ale_rust_rls_toolchain*
+  Type: |String|
+  Default: `'nightly'`
+
+  This option can be set to change the toolchain used for `rls`. Possible
+  values include `'nightly'`, `'beta'`, and `'stable'`.
+
+  The `rls` server will only be started once per executable.
+
+
 ===============================================================================
 rustc                                                          *ale-rust-rustc*
 

test/command_callback/test_rust_rls_callbacks.vader

@@ -1,7 +1,9 @@
 Before:
   Save g:ale_rust_rls_executable
+  Save g:ale_rust_rls_toolchain
 
   unlet! g:ale_rust_rls_executable
+  unlet! g:ale_rust_rls_toolchain
 
   runtime ale_linters/rust/rls.vim
 
@@ -16,7 +18,14 @@ After:
 Execute(The default executable path should be correct):
   AssertEqual 'rls', ale_linters#rust#rls#GetExecutable(bufnr(''))
   AssertEqual
-  \ ale#Escape('rls') . ' +nightly',
+  \ ale#Escape('rls') . ' +' . ale#Escape('nightly'),
+  \ ale_linters#rust#rls#GetCommand(bufnr(''))
+
+Execute(The toolchain should be configurable):
+  let g:ale_rust_rls_toolchain = 'stable'
+
+  AssertEqual
+  \ ale#Escape('rls') . ' +' . ale#Escape('stable'),
   \ ale_linters#rust#rls#GetCommand(bufnr(''))
 
 Execute(The language string should be correct):