3 files changed, 18 insertions, 14 deletions
diff --git a/runtime/autoload/health/nvim.vim b/runtime/autoload/health/nvim.vim
index efa3292801..8fcea2e941 100644
--- a/runtime/autoload/health/nvim.vim
+++ b/runtime/autoload/health/nvim.vim
@@ -170,6 +170,17 @@ function! s:check_tmux() abort
           \ ["Set default-terminal in ~/.tmux.conf:\nset-option -g default-terminal \"screen-256color\"",
           \  s:suggest_faq])
   endif
+
+  " check for RGB capabilities
+  let info = system('tmux server-info')
+  let has_tc = stridx(info, " Tc: (flag) true") != -1
+  let has_rgb = stridx(info, " RGB: (flag) true") != -1
+  if !has_tc && !has_rgb
+    call health#report_warn(
+          \ "Neither Tc nor RGB capability set. True colors are disabled. |'termguicolors'| won't work properly.",
+          \ ["Put this in your ~/.tmux.conf and replace XXX by your $TERM outside of tmux:\nset-option -sa terminal-overrides ',XXX:RGB'",
+          \  "For older tmux versions use this instead:\nset-option -ga terminal-overrides ',XXX:Tc'"])
+  endif
 endfunction
 
 function! s:check_terminal() abort
diff --git a/runtime/autoload/health/provider.vim b/runtime/autoload/health/provider.vim
index 8f364a2ace..29bbee4888 100644
--- a/runtime/autoload/health/provider.vim
+++ b/runtime/autoload/health/provider.vim
@@ -106,7 +106,8 @@ endfunction
 
 " Fetch the contents of a URL.
 function! s:download(url) abort
-  if executable('curl')
+  let has_curl = executable('curl')
+  if has_curl && system(['curl', '-V']) =~# 'Protocols:.*https'
     let rv = s:system(['curl', '-sL', a:url], '', 1, 1)
     return s:shell_error ? 'curl error with '.a:url.': '.s:shell_error : rv
   elseif executable('python')
@@ -124,7 +125,9 @@ function! s:download(url) abort
           \ ? 'python urllib.request error: '.s:shell_error
           \ : rv
   endif
-  return 'missing `curl` and `python`, cannot make pypi request'
+  return 'missing `curl` '
+          \ .(has_curl ? '(with HTTPS support) ' : '')
+          \ .'and `python`, cannot make web request'
 endfunction
 
 " Check for clipboard tools.
diff --git a/runtime/autoload/spellfile.vim b/runtime/autoload/spellfile.vim
index 9ec6091218..c0ef51cdfe 100644
--- a/runtime/autoload/spellfile.vim
+++ b/runtime/autoload/spellfile.vim
@@ -195,16 +195,6 @@ function! spellfile#GetDirChoices()
 endfunc
 
 function! spellfile#WritableSpellDir()
-  " Always use the $XDG_DATA_HOME/nvim/site directory
-  if exists('$XDG_DATA_HOME')
-    return $XDG_DATA_HOME . "/nvim/site/spell"
-  elseif !(has('win32') || has('win64'))
-    return $HOME . "/.local/share/nvim/site/spell"
-  endif
-  for dir in split(&rtp, ',')
-    if filewritable(dir) == 2
-      return dir . "/spell"
-    endif
-  endfor
-  return ''
+  " Always use the $XDG_DATA_HOME/…/site directory
+  return stdpath('data').'/site/spell'
 endfunction