diff --git a/autoload/syntastic/log.vim b/autoload/syntastic/log.vim
index 7570942b..f84eb1d2 100644
--- a/autoload/syntastic/log.vim
+++ b/autoload/syntastic/log.vim
@@ -120,7 +120,7 @@ function! syntastic#log#debugDump(level) " {{{2
         return
     endif
 
-    call syntastic#log#debugShowVariables( a:level, sort(keys(g:SYNTASTIC_DEFAULTS)) )
+    call syntastic#log#debugShowVariables( a:level, sort(keys(g:_SYNTASTIC_DEFAULTS)) )
 endfunction " }}}2
 
 " }}}1
@@ -155,7 +155,7 @@ function! s:_logRedirect(on) " {{{2
 endfunction " }}}2
 
 function! s:_logTimestamp() " {{{2
-    return 'syntastic: ' . split(reltimestr(reltime(g:SYNTASTIC_START)))[0] . ': '
+    return 'syntastic: ' . split(reltimestr(reltime(g:_SYNTASTIC_START)))[0] . ': '
 endfunction " }}}2
 
 function! s:_formatVariable(name) " {{{2
diff --git a/autoload/syntastic/util.vim b/autoload/syntastic/util.vim
index 9aa24928..27ef34b2 100644
--- a/autoload/syntastic/util.vim
+++ b/autoload/syntastic/util.vim
@@ -274,7 +274,7 @@ endfunction " }}}2
 
 function! syntastic#util#dictFilter(errors, filter) " {{{2
     let rules = s:_translateFilter(a:filter)
-    " call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, "applying filter:", rules)
+    " call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, "applying filter:", rules)
     try
         call filter(a:errors, rules)
     catch /\m^Vim\%((\a\+)\)\=:E/
@@ -287,7 +287,7 @@ endfunction " }}}2
 " (hopefully high resolution) since program start
 " TODO: This assumes reltime() returns a list of integers.
 function! syntastic#util#stamp() " {{{2
-    return reltime(g:SYNTASTIC_START)
+    return reltime(g:_SYNTASTIC_START)
 endfunction " }}}2
 
 " }}}1
diff --git a/plugin/syntastic.vim b/plugin/syntastic.vim
index 875fe986..d18cf93b 100644
--- a/plugin/syntastic.vim
+++ b/plugin/syntastic.vim
@@ -15,12 +15,12 @@ endif
 let g:loaded_syntastic_plugin = 1
 
 if has('reltime')
-    let g:SYNTASTIC_START = reltime()
-    lockvar! g:SYNTASTIC_START
+    let g:_SYNTASTIC_START = reltime()
+    lockvar! g:_SYNTASTIC_START
 endif
 
-let g:SYNTASTIC_VERSION = '3.5.0-72'
-lockvar g:SYNTASTIC_VERSION
+let g:_SYNTASTIC_VERSION = '3.5.0-72'
+lockvar g:_SYNTASTIC_VERSION
 
 " Sanity checks {{{1
 
@@ -39,24 +39,24 @@ for s:feature in [
     endif
 endfor
 
-let s:running_windows = syntastic#util#isRunningWindows()
-lockvar s:running_windows
+let s:_running_windows = syntastic#util#isRunningWindows()
+lockvar s:_running_windows
 
-if !s:running_windows && executable('uname')
+if !s:_running_windows && executable('uname')
     try
-        let s:uname = system('uname')
+        let s:_uname = system('uname')
     catch /\m^Vim\%((\a\+)\)\=:E484/
         call syntastic#log#error("your shell " . &shell . " can't handle traditional UNIX syntax for redirections")
         finish
     endtry
-    lockvar s:uname
+    lockvar s:_uname
 endif
 
 " }}}1
 
 " Defaults {{{1
 
-let g:SYNTASTIC_DEFAULTS = {
+let g:_SYNTASTIC_DEFAULTS = {
         \ 'aggregate_errors':         0,
         \ 'always_populate_loc_list': 0,
         \ 'auto_jump':                0,
@@ -71,7 +71,7 @@ let g:SYNTASTIC_DEFAULTS = {
         \ 'enable_highlighting':      1,
         \ 'enable_signs':             1,
         \ 'error_symbol':             '>>',
-        \ 'exit_checks':              !(s:running_windows && &shell =~? '\m\<cmd\.exe$'),
+        \ 'exit_checks':              !(s:_running_windows && &shell =~? '\m\<cmd\.exe$'),
         \ 'filetype_map':             {},
         \ 'full_redraws':             !(has('gui_running') || has('gui_macvim')),
         \ 'id_checkers':              1,
@@ -86,11 +86,11 @@ let g:SYNTASTIC_DEFAULTS = {
         \ 'style_warning_symbol':     'S>',
         \ 'warning_symbol':           '>>'
     \ }
-lockvar! g:SYNTASTIC_DEFAULTS
+lockvar! g:_SYNTASTIC_DEFAULTS
 
-for s:key in keys(g:SYNTASTIC_DEFAULTS)
+for s:key in keys(g:_SYNTASTIC_DEFAULTS)
     if !exists('g:syntastic_' . s:key)
-        let g:syntastic_{s:key} = copy(g:SYNTASTIC_DEFAULTS[s:key])
+        let g:syntastic_{s:key} = copy(g:_SYNTASTIC_DEFAULTS[s:key])
     endif
 endfor
 
@@ -110,7 +110,7 @@ endif
 
 " Debug {{{1
 
-let s:DEBUG_DUMP_OPTIONS = [
+let s:_DEBUG_DUMP_OPTIONS = [
         \ 'shell',
         \ 'shellcmdflag',
         \ 'shellpipe',
@@ -121,23 +121,23 @@ let s:DEBUG_DUMP_OPTIONS = [
         \ 'shellxquote'
     \ ]
 if v:version > 703 || (v:version == 703 && has('patch446'))
-    call add(s:DEBUG_DUMP_OPTIONS, 'shellxescape')
+    call add(s:_DEBUG_DUMP_OPTIONS, 'shellxescape')
 endif
-lockvar! s:DEBUG_DUMP_OPTIONS
+lockvar! s:_DEBUG_DUMP_OPTIONS
 
 " debug constants
-let     g:SYNTASTIC_DEBUG_TRACE         = 1
-lockvar g:SYNTASTIC_DEBUG_TRACE
-let     g:SYNTASTIC_DEBUG_LOCLIST       = 2
-lockvar g:SYNTASTIC_DEBUG_LOCLIST
-let     g:SYNTASTIC_DEBUG_NOTIFICATIONS = 4
-lockvar g:SYNTASTIC_DEBUG_NOTIFICATIONS
-let     g:SYNTASTIC_DEBUG_AUTOCOMMANDS  = 8
-lockvar g:SYNTASTIC_DEBUG_AUTOCOMMANDS
-let     g:SYNTASTIC_DEBUG_VARIABLES     = 16
-lockvar g:SYNTASTIC_DEBUG_VARIABLES
-let     g:SYNTASTIC_DEBUG_CHECKERS      = 32
-lockvar g:SYNTASTIC_DEBUG_CHECKERS
+let     g:_SYNTASTIC_DEBUG_TRACE         = 1
+lockvar g:_SYNTASTIC_DEBUG_TRACE
+let     g:_SYNTASTIC_DEBUG_LOCLIST       = 2
+lockvar g:_SYNTASTIC_DEBUG_LOCLIST
+let     g:_SYNTASTIC_DEBUG_NOTIFICATIONS = 4
+lockvar g:_SYNTASTIC_DEBUG_NOTIFICATIONS
+let     g:_SYNTASTIC_DEBUG_AUTOCOMMANDS  = 8
+lockvar g:_SYNTASTIC_DEBUG_AUTOCOMMANDS
+let     g:_SYNTASTIC_DEBUG_VARIABLES     = 16
+lockvar g:_SYNTASTIC_DEBUG_VARIABLES
+let     g:_SYNTASTIC_DEBUG_CHECKERS      = 32
+lockvar g:_SYNTASTIC_DEBUG_CHECKERS
 
 " }}}1
 
@@ -207,20 +207,20 @@ endif
 
 function! s:BufReadPostHook() " {{{2
     if g:syntastic_check_on_open
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_AUTOCOMMANDS,
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_AUTOCOMMANDS,
             \ 'autocmd: BufReadPost, buffer ' . bufnr("") . ' = ' . string(bufname(str2nr(bufnr("")))))
         call s:UpdateErrors(1)
     endif
 endfunction " }}}2
 
 function! s:BufWritePostHook() " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_AUTOCOMMANDS,
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_AUTOCOMMANDS,
         \ 'autocmd: BufWritePost, buffer ' . bufnr("") . ' = ' . string(bufname(str2nr(bufnr("")))))
     call s:UpdateErrors(1)
 endfunction " }}}2
 
 function! s:BufEnterHook() " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_AUTOCOMMANDS,
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_AUTOCOMMANDS,
         \ 'autocmd: BufEnter, buffer ' . bufnr("") . ' = ' . string(bufname(str2nr(bufnr("")))) .
         \ ', &buftype = ' . string(&buftype))
     if &buftype == ''
@@ -239,7 +239,7 @@ function! s:BufEnterHook() " {{{2
 endfunction " }}}2
 
 function! s:QuitPreHook() " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_AUTOCOMMANDS,
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_AUTOCOMMANDS,
         \ 'autocmd: QuitPre, buffer ' . bufnr("") . ' = ' . string(bufname(str2nr(bufnr("")))))
     let b:syntastic_skip_checks = get(b:, 'syntastic_skip_checks', 0) || !syntastic#util#var('check_on_wq')
     call SyntasticLoclistHide()
@@ -251,10 +251,10 @@ endfunction " }}}2
 
 "refresh and redraw all the error info for this buf when saving or reading
 function! s:UpdateErrors(auto_invoked, ...) " {{{2
-    call syntastic#log#debugShowVariables(g:SYNTASTIC_DEBUG_TRACE, 'version')
-    call syntastic#log#debugShowOptions(g:SYNTASTIC_DEBUG_TRACE, s:DEBUG_DUMP_OPTIONS)
-    call syntastic#log#debugDump(g:SYNTASTIC_DEBUG_VARIABLES)
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'UpdateErrors' . (a:auto_invoked ? ' (auto)' : '') .
+    call syntastic#log#debugShowVariables(g:_SYNTASTIC_DEBUG_TRACE, 'version')
+    call syntastic#log#debugShowOptions(g:_SYNTASTIC_DEBUG_TRACE, s:_DEBUG_DUMP_OPTIONS)
+    call syntastic#log#debugDump(g:_SYNTASTIC_DEBUG_VARIABLES)
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'UpdateErrors' . (a:auto_invoked ? ' (auto)' : '') .
         \ ': ' . (a:0 ? join(a:000) : 'default checkers'))
     if s:skipFile()
         return
@@ -278,11 +278,11 @@ function! s:UpdateErrors(auto_invoked, ...) " {{{2
 
     let w:syntastic_loclist_set = 0
     if syntastic#util#var('always_populate_loc_list') || do_jump
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: setloclist (new)')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: setloclist (new)')
         call setloclist(0, loclist.getRaw())
         let w:syntastic_loclist_set = 1
         if run_checks && do_jump && !loclist.isEmpty()
-            call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: jump')
+            call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: jump')
             silent! lrewind
 
             " XXX: Vim doesn't call autocmd commands in a predictible
@@ -307,15 +307,15 @@ endfunction " }}}2
 
 "detect and cache all syntax errors in this buffer
 function! s:CacheErrors(checker_names) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'CacheErrors: ' .
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'CacheErrors: ' .
         \ (len(a:checker_names) ? join(a:checker_names) : 'default checkers'))
     call s:ClearCache()
     let newLoclist = g:SyntasticLoclist.New([])
 
     if !s:skipFile()
         " debug logging {{{3
-        call syntastic#log#debugShowVariables(g:SYNTASTIC_DEBUG_TRACE, 'aggregate_errors')
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'getcwd() = ' . getcwd())
+        call syntastic#log#debugShowVariables(g:_SYNTASTIC_DEBUG_TRACE, 'aggregate_errors')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'getcwd() = ' . getcwd())
         " }}}3
 
         let filetypes = s:resolveFiletypes()
@@ -333,12 +333,12 @@ function! s:CacheErrors(checker_names) " {{{2
         for checker in clist
             let cname = checker.getFiletype() . '/' . checker.getName()
             if !checker.isAvailable()
-                call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'CacheErrors: Checker ' . cname . ' is not available')
+                call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'CacheErrors: Checker ' . cname . ' is not available')
                 let unavailable_checkers += 1
                 continue
             endif
 
-            call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'CacheErrors: Invoking checker: ' . cname)
+            call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'CacheErrors: Invoking checker: ' . cname)
 
             let loclist = checker.getLocList()
 
@@ -349,7 +349,7 @@ function! s:CacheErrors(checker_names) " {{{2
                 call add(names, cname)
                 if checker.getWantSort() && !sort_aggregated_errors
                     call loclist.sort()
-                    call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'sorted:', loclist)
+                    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'sorted:', loclist)
                 endif
 
                 let newLoclist = newLoclist.extend(loclist)
@@ -382,15 +382,15 @@ function! s:CacheErrors(checker_names) " {{{2
                     call syntastic#log#warn('checkers ' . join(a:checker_names, ', ') . ' are not available')
                 endif
             else
-                call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'CacheErrors: no checkers available for ' . &filetype)
+                call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'CacheErrors: no checkers available for ' . &filetype)
             endif
         endif
         " }}}3
 
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'aggregated:', newLoclist)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'aggregated:', newLoclist)
         if sort_aggregated_errors
             call newLoclist.sort()
-            call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'sorted:', newLoclist)
+            call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'sorted:', newLoclist)
         endif
     endif
 
@@ -429,7 +429,7 @@ endfunction " }}}2
 "   'returns' - a list of valid exit codes for the checker
 " @vimlint(EVL102, 1, l:env_save)
 function! SyntasticMake(options) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'SyntasticMake: called with options:', a:options)
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'SyntasticMake: called with options:', a:options)
 
     " save options and locale env variables {{{3
     let old_shellredir = &shellredir
@@ -476,14 +476,14 @@ function! SyntasticMake(options) " {{{2
     endif
     " }}}3
 
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'checker output:', err_lines)
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'checker output:', err_lines)
 
     if has_key(a:options, 'Preprocess')
         let err_lines = call(a:options['Preprocess'], [err_lines])
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'preprocess (external):', err_lines)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'preprocess (external):', err_lines)
     elseif has_key(a:options, 'preprocess')
         let err_lines = call('syntastic#preprocess#' . a:options['preprocess'], [err_lines])
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'preprocess:', err_lines)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'preprocess:', err_lines)
     endif
     lgetexpr err_lines
 
@@ -509,11 +509,11 @@ function! SyntasticMake(options) " {{{2
     let &shellredir = old_shellredir
     " }}}3
 
-    if !s:running_windows && (s:uname() =~ "FreeBSD" || s:uname() =~ "OpenBSD")
+    if !s:_running_windows && (s:uname() =~ "FreeBSD" || s:uname() =~ "OpenBSD")
         call syntastic#util#redraw(g:syntastic_full_redraws)
     endif
 
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'raw loclist:', errors)
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'raw loclist:', errors)
 
     if syntastic#util#var('exit_checks') && has_key(a:options, 'returns') && index(a:options['returns'], v:shell_error) == -1
         throw 'Syntastic: checker error'
@@ -532,12 +532,12 @@ function! SyntasticMake(options) " {{{2
         for rule in a:options['Postprocess']
             let errors = call(rule, [errors])
         endfor
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'postprocess (external):', errors)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'postprocess (external):', errors)
     elseif has_key(a:options, 'postprocess') && !empty(a:options['postprocess'])
         for rule in a:options['postprocess']
             let errors = call('syntastic#postprocess#' . rule, [errors])
         endfor
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'postprocess:', errors)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'postprocess:', errors)
     endif
 
     return errors
@@ -578,7 +578,7 @@ function! s:skipFile() " {{{2
         \ !filereadable(fname) || getwinvar(0, '&diff') || s:ignoreFile(fname) ||
         \ fnamemodify(fname, ':e') =~? g:syntastic_ignore_extensions
     if skip
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'skipFile: skipping')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'skipFile: skipping')
     endif
     return skip
 endfunction " }}}2
@@ -632,7 +632,7 @@ function! s:bashHack() " {{{2
     if g:syntastic_bash_hack
         if !exists('s:shell_is_bash')
             let s:shell_is_bash =
-                \ !s:running_windows &&
+                \ !s:_running_windows &&
                 \ (s:uname() !~# "FreeBSD") && (s:uname() !~# "OpenBSD") &&
                 \ &shell =~# '\m\<bash$'
         endif
@@ -644,11 +644,11 @@ function! s:bashHack() " {{{2
 endfunction " }}}2
 
 function! s:uname() " {{{2
-    if !exists('s:uname')
-        let s:uname = system('uname')
-        lockvar s:uname
+    if !exists('s:_uname')
+        let s:_uname = system('uname')
+        lockvar s:_uname
     endif
-    return s:uname
+    return s:_uname
 endfunction " }}}2
 
 " }}}1
diff --git a/plugin/syntastic/autoloclist.vim b/plugin/syntastic/autoloclist.vim
index 9a5b68fe..efda8952 100644
--- a/plugin/syntastic/autoloclist.vim
+++ b/plugin/syntastic/autoloclist.vim
@@ -13,12 +13,12 @@ function! g:SyntasticAutoloclistNotifier.New() " {{{2
 endfunction " }}}2
 
 function! g:SyntasticAutoloclistNotifier.refresh(loclist) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'autoloclist: refresh')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'autoloclist: refresh')
     call g:SyntasticAutoloclistNotifier.AutoToggle(a:loclist)
 endfunction " }}}2
 
 function! g:SyntasticAutoloclistNotifier.AutoToggle(loclist) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'autoloclist: toggle')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'autoloclist: toggle')
     if !a:loclist.isEmpty()
         if syntastic#util#var('auto_loc_list') == 1
             call a:loclist.show()
diff --git a/plugin/syntastic/balloons.vim b/plugin/syntastic/balloons.vim
index ba87ba9e..b4f491ca 100644
--- a/plugin/syntastic/balloons.vim
+++ b/plugin/syntastic/balloons.vim
@@ -36,7 +36,7 @@ endfunction " }}}2
 function! g:SyntasticBalloonsNotifier.reset(loclist) " {{{2
     let b:syntastic_balloons = {}
     if has('balloon_eval')
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'balloons: reset')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'balloons: reset')
         unlet! b:syntastic_balloons
         set noballooneval
     endif
diff --git a/plugin/syntastic/checker.vim b/plugin/syntastic/checker.vim
index fbaf0b1e..5fb46b5b 100644
--- a/plugin/syntastic/checker.vim
+++ b/plugin/syntastic/checker.vim
@@ -59,13 +59,13 @@ function! g:SyntasticChecker.getLocListRaw() " {{{2
     let name = self._filetype . '/' . self._name
     try
         let list = self._locListFunc()
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_TRACE, 'getLocList: checker ' . name . ' returned ' . v:shell_error)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_TRACE, 'getLocList: checker ' . name . ' returned ' . v:shell_error)
     catch /\m\C^Syntastic: checker error$/
         let list = []
         call syntastic#log#error('checker ' . name . ' returned abnormal status ' . v:shell_error)
     endtry
     call self._populateHighlightRegexes(list)
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, name . ' raw:', list)
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, name . ' raw:', list)
     call self._quietMessages(list)
     return list
 endfunction " }}}2
@@ -85,9 +85,9 @@ endfunction " }}}2
 function! g:SyntasticChecker.log(msg, ...) " {{{2
     let leader = self._filetype . '/' . self._name . ': '
     if a:0 > 0
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_CHECKERS, leader . a:msg, a:1)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_CHECKERS, leader . a:msg, a:1)
     else
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_CHECKERS, leader . a:msg)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_CHECKERS, leader . a:msg)
     endif
 endfunction " }}}2
 
@@ -132,11 +132,11 @@ function! g:SyntasticChecker._quietMessages(errors) " {{{2
         call syntastic#log#warn('ignoring invalid syntastic_' . name . '_quiet_messages')
     endtry
 
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'quiet_messages filter:', quiet_filters)
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'quiet_messages filter:', quiet_filters)
 
     if !empty(quiet_filters)
         call syntastic#util#dictFilter(a:errors, quiet_filters)
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_LOCLIST, 'filtered by quiet_messages:', a:errors)
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_LOCLIST, 'filtered by quiet_messages:', a:errors)
     endif
 endfunction " }}}2
 
diff --git a/plugin/syntastic/cursor.vim b/plugin/syntastic/cursor.vim
index 5ff6f5a8..629cf2d6 100644
--- a/plugin/syntastic/cursor.vim
+++ b/plugin/syntastic/cursor.vim
@@ -18,7 +18,7 @@ endfunction " }}}2
 
 function! g:SyntasticCursorNotifier.refresh(loclist) " {{{2
     if self.enabled() && !a:loclist.isEmpty()
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'cursor: refresh')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'cursor: refresh')
         let b:syntastic_messages = copy(a:loclist.messages(bufnr('')))
         let b:syntastic_line = -1
         let b:syntastic_cursor_columns = a:loclist.getCursorColumns()
@@ -29,7 +29,7 @@ endfunction " }}}2
 
 " @vimlint(EVL103, 1, a:loclist)
 function! g:SyntasticCursorNotifier.reset(loclist) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'cursor: reset')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'cursor: reset')
     autocmd! syntastic CursorMoved
     unlet! b:syntastic_messages
     let b:syntastic_line = -1
diff --git a/plugin/syntastic/highlighting.vim b/plugin/syntastic/highlighting.vim
index 576b2383..0f027b17 100644
--- a/plugin/syntastic/highlighting.vim
+++ b/plugin/syntastic/highlighting.vim
@@ -32,7 +32,7 @@ endfunction " }}}2
 " Sets error highlights in the cuirrent window
 function! g:SyntasticHighlightingNotifier.refresh(loclist) " {{{2
     if self.enabled()
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'highlighting: refresh')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'highlighting: refresh')
         call self._reset()
         let buf = bufnr('')
         let issues = filter(a:loclist.copyRaw(), 'v:val["bufnr"] == buf')
@@ -63,7 +63,7 @@ endfunction " }}}2
 " @vimlint(EVL103, 1, a:loclist)
 function! g:SyntasticHighlightingNotifier.reset(loclist) " {{{2
     if s:has_highlighting
-        call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'highlighting: reset')
+        call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'highlighting: reset')
         call self._reset()
     endif
 endfunction " }}}2
diff --git a/plugin/syntastic/loclist.vim b/plugin/syntastic/loclist.vim
index f16d0a1e..fb7cefb7 100644
--- a/plugin/syntastic/loclist.vim
+++ b/plugin/syntastic/loclist.vim
@@ -281,14 +281,14 @@ function! g:SyntasticLoclist.setloclist() " {{{2
         let w:syntastic_loclist_set = 0
     endif
     let replace = g:syntastic_reuse_loc_lists && w:syntastic_loclist_set
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: setloclist ' . (replace ? '(replace)' : '(new)'))
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: setloclist ' . (replace ? '(replace)' : '(new)'))
     call setloclist(0, self.getRaw(), replace ? 'r' : ' ')
     let w:syntastic_loclist_set = 1
 endfunction " }}}2
 
 "display the cached errors for this buf in the location list
 function! g:SyntasticLoclist.show() " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: show')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: show')
     call self.setloclist()
 
     if !self.isEmpty()
@@ -323,7 +323,7 @@ endfunction " }}}2
 " Non-method functions {{{1
 
 function! SyntasticLoclistHide() " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: hide')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'loclist: hide')
     silent! lclose
 endfunction " }}}2
 
diff --git a/plugin/syntastic/modemap.vim b/plugin/syntastic/modemap.vim
index 525397cf..6dd9490d 100644
--- a/plugin/syntastic/modemap.vim
+++ b/plugin/syntastic/modemap.vim
@@ -63,7 +63,7 @@ function! g:SyntasticModeMap.echoMode() " {{{2
 endfunction " }}}2
 
 function! g:SyntasticModeMap.modeInfo(...) " {{{2
-    echomsg 'Syntastic version: ' . g:SYNTASTIC_VERSION
+    echomsg 'Syntastic version: ' . g:_SYNTASTIC_VERSION
     let type = a:0 ? a:1 : &filetype
     echomsg 'Info for filetype: ' . type
 
diff --git a/plugin/syntastic/notifiers.vim b/plugin/syntastic/notifiers.vim
index 2a58bd94..11b72c6a 100644
--- a/plugin/syntastic/notifiers.vim
+++ b/plugin/syntastic/notifiers.vim
@@ -5,11 +5,11 @@ let g:loaded_syntastic_notifiers = 1
 
 let g:SyntasticNotifiers = {}
 
-let s:NOTIFIER_TYPES = ['signs', 'balloons', 'highlighting', 'cursor', 'autoloclist']
-lockvar! s:NOTIFIER_TYPES
+let s:_NOTIFIER_TYPES = ['signs', 'balloons', 'highlighting', 'cursor', 'autoloclist']
+lockvar! s:_NOTIFIER_TYPES
 
-let s:PERSISTENT_NOTIFIERS = ['signs', 'balloons']
-lockvar! s:PERSISTENT_NOTIFIERS
+let s:_PERSISTENT_NOTIFIERS = ['signs', 'balloons']
+lockvar! s:_PERSISTENT_NOTIFIERS
 
 " Public methods {{{1
 
@@ -28,11 +28,11 @@ function! g:SyntasticNotifiers.refresh(loclist) " {{{2
         return
     endif
 
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'notifiers: refresh')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'notifiers: refresh')
     for type in self._enabled_types
         let class = substitute(type, '\m.*', 'Syntastic\u&Notifier', '')
         if !has_key(g:{class}, 'enabled') || self._notifier[type].enabled()
-            if index(s:PERSISTENT_NOTIFIERS, type) > -1
+            if index(s:_PERSISTENT_NOTIFIERS, type) > -1
                 " refresh only if loclist has changed since last call
                 if !exists('b:syntastic_' . type . '_stamp')
                     let b:syntastic_{type}_stamp = []
@@ -49,7 +49,7 @@ function! g:SyntasticNotifiers.refresh(loclist) " {{{2
 endfunction " }}}2
 
 function! g:SyntasticNotifiers.reset(loclist) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'notifiers: reset')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'notifiers: reset')
     for type in self._enabled_types
         let class = substitute(type, '\m.*', 'Syntastic\u&Notifier', '')
 
@@ -61,7 +61,7 @@ function! g:SyntasticNotifiers.reset(loclist) " {{{2
         endif
 
         " also reset stamps
-        if index(s:PERSISTENT_NOTIFIERS, type) > -1
+        if index(s:_PERSISTENT_NOTIFIERS, type) > -1
             let b:syntastic_{type}_stamp = []
         endif
     endfor
@@ -73,12 +73,12 @@ endfunction " }}}2
 
 function! g:SyntasticNotifiers._initNotifiers() " {{{2
     let self._notifier = {}
-    for type in s:NOTIFIER_TYPES
+    for type in s:_NOTIFIER_TYPES
         let class = substitute(type, '\m.*', 'Syntastic\u&Notifier', '')
         let self._notifier[type] = g:{class}.New()
     endfor
 
-    let self._enabled_types = copy(s:NOTIFIER_TYPES)
+    let self._enabled_types = copy(s:_NOTIFIER_TYPES)
 endfunction " }}}2
 
 " }}}1
diff --git a/plugin/syntastic/registry.vim b/plugin/syntastic/registry.vim
index cc314d3a..8f50f8af 100644
--- a/plugin/syntastic/registry.vim
+++ b/plugin/syntastic/registry.vim
@@ -5,7 +5,7 @@ let g:loaded_syntastic_registry = 1
 
 " Initialisation {{{1
 
-let s:DEFAULT_CHECKERS = {
+let s:_DEFAULT_CHECKERS = {
         \ 'actionscript':['mxmlc'],
         \ 'ada':         ['gcc'],
         \ 'applescript': ['osacompile'],
@@ -94,9 +94,9 @@ let s:DEFAULT_CHECKERS = {
         \ 'zpt':         ['zptlint'],
         \ 'zsh':         ['zsh', 'shellcheck']
     \ }
-lockvar! s:DEFAULT_CHECKERS
+lockvar! s:_DEFAULT_CHECKERS
 
-let s:DEFAULT_FILETYPE_MAP = {
+let s:_DEFAULT_FILETYPE_MAP = {
         \ 'gentoo-metadata': 'xml',
         \ 'groff': 'nroff',
         \ 'lhaskell': 'haskell',
@@ -106,7 +106,7 @@ let s:DEFAULT_FILETYPE_MAP = {
         \ 'sgml': 'docbk',
         \ 'sgmllnx': 'docbk',
     \ }
-lockvar! s:DEFAULT_FILETYPE_MAP
+lockvar! s:_DEFAULT_FILETYPE_MAP
 
 let g:SyntasticRegistry = {}
 
@@ -152,7 +152,7 @@ function! g:SyntasticRegistry.getCheckers(ftalias, hints_list) " {{{2
         \ !empty(a:hints_list) ? syntastic#util#unique(a:hints_list) :
         \ exists('b:syntastic_checkers') ? b:syntastic_checkers :
         \ exists('g:syntastic_' . ft . '_checkers') ? g:syntastic_{ft}_checkers :
-        \ get(s:DEFAULT_CHECKERS, ft, 0)
+        \ get(s:_DEFAULT_CHECKERS, ft, 0)
 
     return type(names) == type([]) ?
         \ self._filterCheckersByName(checkers_map, names) : [checkers_map[keys(checkers_map)[0]]]
@@ -165,9 +165,9 @@ function! g:SyntasticRegistry.getCheckersAvailable(ftalias, hints_list) " {{{2
 endfunction " }}}2
 
 function! g:SyntasticRegistry.getKnownFiletypes() " {{{2
-    let types = keys(s:DEFAULT_CHECKERS)
+    let types = keys(s:_DEFAULT_CHECKERS)
 
-    call extend(types, keys(s:DEFAULT_FILETYPE_MAP))
+    call extend(types, keys(s:_DEFAULT_FILETYPE_MAP))
 
     if exists('g:syntastic_filetype_map')
         call extend(types, keys(g:syntastic_filetype_map))
@@ -262,7 +262,7 @@ endfunction " }}}2
 "resolve filetype aliases, and replace - with _ otherwise we cant name
 "syntax checker functions legally for filetypes like "gentoo-metadata"
 function! s:_normaliseFiletype(ftalias) " {{{2
-    let ft = get(s:DEFAULT_FILETYPE_MAP, a:ftalias, a:ftalias)
+    let ft = get(s:_DEFAULT_FILETYPE_MAP, a:ftalias, a:ftalias)
     let ft = get(g:syntastic_filetype_map, ft, ft)
     let ft = substitute(ft, '\m-', '_', 'g')
     return ft
diff --git a/plugin/syntastic/signs.vim b/plugin/syntastic/signs.vim
index 24132da0..9d169490 100644
--- a/plugin/syntastic/signs.vim
+++ b/plugin/syntastic/signs.vim
@@ -36,7 +36,7 @@ function! g:SyntasticSignsNotifier.enabled() " {{{2
 endfunction " }}}2
 
 function! g:SyntasticSignsNotifier.refresh(loclist) " {{{2
-    call syntastic#log#debug(g:SYNTASTIC_DEBUG_NOTIFICATIONS, 'signs: refresh')
+    call syntastic#log#debug(g:_SYNTASTIC_DEBUG_NOTIFICATIONS, 'signs: refresh')
     let old_signs = copy(self._bufSignIds())
     if self.enabled()
         call self._signErrors(a:loclist)