vimrc: no cargo check on standalone .rs files

cargo check on a file without Cargo.toml needs nightly -Zscript, so
rust-analyzer's checkOnSave warned on every save. Turn it off when the
server starts on a standalone file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 14 insertions, 8 deletions

diff --git a/core/vimrc b/core/vimrc
index a2b40c4..06d1782 100644
--- a/core/vimrc
+++ b/core/vimrc
@@ -181,6 +181,16 @@ endfunction
 " else it loads nothing for them (no gd/completion). The list is shared by reference with
 " the init options below (covers the first file) and pushed as config for later files.
 let g:ra_detached = []
+" checkOnSave runs `cargo check` on the file, which needs nightly -Zscript for a file with
+" no Cargo.toml; RustDetach turns it off when the server starts on a standalone file.
+let g:ra_init = {
+  \   'completion': {
+  \     'autoimport': { 'enable': v:true },
+  \     'postfix':    { 'enable': v:true },
+  \   },
+  \   'checkOnSave': v:true,
+  \   'detachedFiles': g:ra_detached,
+  \ }
 function! RustDetach() abort
   if !exists('g:lsp_loaded')
     return
@@ -190,6 +200,9 @@ function! RustDetach() abort
     return
   endif
   call add(g:ra_detached, l:p)
+  if lsp#get_server_status('rust-analyzer') !~# '^\(running\|starting\)$'
+    let g:ra_init['checkOnSave'] = v:false
+  endif
   if lsp#get_server_status('rust-analyzer') ==# 'running'
     call lsp#update_workspace_config('rust-analyzer', {'rust-analyzer': {'detachedFiles': copy(g:ra_detached)}})
   endif
@@ -206,14 +219,7 @@ if executable(expand('~/.cargo/bin/rust-analyzer'))
   \   'cmd': {server_info -> [expand('~/.cargo/bin/rust-analyzer')]},
   \   'allowlist': ['rust'],
   \   'root_uri': {server_info -> lsp#utils#path_to_uri(RustRoot())},
-  \   'initialization_options': {
-  \     'completion': {
-  \       'autoimport': { 'enable': v:true },
-  \       'postfix':    { 'enable': v:true },
-  \     },
-  \     'checkOnSave': v:true,
-  \     'detachedFiles': g:ra_detached,
-  \   },
+  \   'initialization_options': g:ra_init,
   \   'workspace_config': {'rust-analyzer': {'detachedFiles': g:ra_detached}},
   \ })
 endif