runtime(vim): Improve Vim9 and legacy-script comment highlighting (#13104)

This is a first-pass attempt to limit matching of Vim9 and legacy-script
comments to the appropriate syntactic contexts.

Vim9-script comments are highlighted at top level in a Vim9-script file,
in all :def functions, and in all :autocmd and :commmand command blocks.
Legacy-script comments are highlighted at top level in a legacy script
file, in all :func functions and in the Vim9-script preamble before the
:vim9script marker command.

Fixes #13047, #11307 and #9587.

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

30 files changed, 622 insertions, 91 deletions

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index f8ea87ec1f..ac127f0c17 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -222,6 +222,7 @@ runtime/ftplugin/typescript.vim		@dkearns
 runtime/ftplugin/typescriptreact.vim	@dkearns
 runtime/ftplugin/unison.vim		@chuwy
 runtime/ftplugin/vdf.vim		@ObserverOfTime
+runtime/ftplugin/vim.vim		@dkearns
 runtime/ftplugin/wast.vim		@rhysd
 runtime/ftplugin/wget.vim		@dkearns
 runtime/ftplugin/wget2.vim		@dkearns
diff --git a/runtime/ftplugin/vim.vim b/runtime/ftplugin/vim.vim
index 575af7405c..a8636f4c81 100644
--- a/runtime/ftplugin/vim.vim
+++ b/runtime/ftplugin/vim.vim
@@ -1,7 +1,7 @@
 " Vim filetype plugin
-" Language:	Vim
-" Maintainer:	The Vim Project <https://github.com/vim/vim>
-" Last Change:	2023 Aug 10
+" Language:		Vim
+" Maintainer:		Doug Kearns <dougkearns@gmail.com>
+" Last Change:		2024 Apr 08
 " Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 " Only do this when not done yet for this buffer
@@ -50,7 +50,7 @@ setlocal isk+=#
 setlocal keywordprg=:help
 
 " Comments starts with # in Vim9 script.  We have to guess which one to use.
-if "\n" .. getline(1, 10)->join("\n") =~# '\n\s*vim9\%[script]\>'
+if "\n" .. getline(1, 32)->join("\n") =~# '\n\s*vim9\%[script]\>'
   setlocal commentstring=#%s
 else
   setlocal commentstring=\"%s
diff --git a/runtime/syntax/generator/gen_syntax_vim.vim b/runtime/syntax/generator/gen_syntax_vim.vim
index da093ee6b5..d320bdbda8 100644
--- a/runtime/syntax/generator/gen_syntax_vim.vim
+++ b/runtime/syntax/generator/gen_syntax_vim.vim
@@ -3,7 +3,7 @@
 " Maintainer: Hirohito Higashi (h_east)
 " URL: https://github.com/vim-jp/syntax-vim-ex
 " Last Change: 2024 Apr 07
-" Version: 2.1.0
+" Version: 2.1.1
 
 let s:keepcpo= &cpo
 set cpo&vim
@@ -286,6 +286,7 @@ function! s:get_vim_command_type(cmd_name)
 	\	'append', 'insert',
 	\	'Next', 'Print', 'X',
 	\	'new', 'popup',
+	\	'vim9script',
 	\ ]
 	" Required for original behavior
 	" \	'global', 'vglobal'
diff --git a/runtime/syntax/generator/vim.vim.base b/runtime/syntax/generator/vim.vim.base
index 9ab923c4f4..7c6a9a073d 100644
--- a/runtime/syntax/generator/vim.vim.base
+++ b/runtime/syntax/generator/vim.vim.base
@@ -19,6 +19,8 @@ endif
 let s:keepcpo= &cpo
 set cpo&vim
 
+let s:vim9script = "\n" .. getline(1, 32)->join("\n") =~# '\n\s*vim9\%[script]\>'
+
 " vimTodo: contains common special-notices for comments {{{2
 " Use the vimCommentGroup cluster to add your own.
 syn keyword vimTodo contained	COMBAK	FIXME	TODO	XXX
@@ -156,13 +158,13 @@ endif
 " Numbers {{{2
 " =======
 syn case ignore
-syn match	vimNumber	'\<\d\+\%(\.\d\+\%(e[+-]\=\d\+\)\=\)\='	skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
-syn match	vimNumber	'\<0b[01]\+'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
-syn match	vimNumber	'\<0o\=\o\+'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
-syn match	vimNumber	'\<0x\x\+'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
-syn match	vimNumber	'\<0z\>'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
-syn match	vimNumber	'\<0z\%(\x\x\)\+\%(\.\%(\x\x\)\+\)*'	skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
-syn match	vimNumber	'\%(^\|\A\)\zs#\x\{6}'		skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,vimComment,vim9Comment
+syn match	vimNumber	'\<\d\+\%(\.\d\+\%(e[+-]\=\d\+\)\=\)\='	skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
+syn match	vimNumber	'\<0b[01]\+'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
+syn match	vimNumber	'\<0o\=\o\+'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
+syn match	vimNumber	'\<0x\x\+'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
+syn match	vimNumber	'\<0z\>'			skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
+syn match	vimNumber	'\<0z\%(\x\x\)\+\%(\.\%(\x\x\)\+\)*'	skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
+syn match	vimNumber	'\%(^\|\A\)\zs#\x\{6}'		skipwhite nextgroup=vimGlobal,vimSubst1,vimCommand,@vimComment
 syn case match
 
 " All vimCommands are contained by vimIsCommand. {{{2
@@ -208,7 +210,7 @@ syn keyword vimFTOption contained	detect indent off on plugin
 
 " Augroup : vimAugroupError removed because long augroups caused sync'ing problems. {{{2
 " ======= : Trade-off: Increasing synclines with slower editing vs augroup END error checking.
-syn cluster vimAugroupList	contains=@vimCmdList,vimFilter,vimFunc,vimLineComment,vimSpecFile,vimOper,vimNumber,vimOperParen,vimComment,vim9Comment,vimString,vimSubst,vimRegister,vimCmplxRepeat,vimNotation,vimCtrlChar,vimFuncVar,vimContinue
+syn cluster vimAugroupList	contains=@vimCmdList,vimFilter,vimFunc,vimLineComment,vimSpecFile,vimOper,vimNumber,vimOperParen,@vimComment,vimString,vimSubst,vimRegister,vimCmplxRepeat,vimNotation,vimCtrlChar,vimFuncVar,vimContinue
 syn match   vimAugroup	"\<aug\%[roup]\>" contains=vimAugroupKey,vimAugroupBang skipwhite nextgroup=vimAugroupBang,vimAutoCmdGroup
 if exists("g:vimsyn_folding") && g:vimsyn_folding =~# 'a'
   syn region  vimAugroup  fold	start="\<aug\%[roup]\>\ze\s\+\%([eE][nN][dD]\)\@!\S\+" matchgroup=vimAugroupKey end="\<aug\%[roup]\>\ze\s\+[eE][nN][dD]\>" contains=vimAutoCmd,@vimAugroupList,vimAugroupkey skipwhite nextgroup=vimAugroupEnd
@@ -299,15 +301,21 @@ syn match	vimUserType	contained	"\<\u\w*\>"
 
 syn cluster vimType contains=vimType,vimCompoundType,vimUserType
 
-" Keymaps: (Vim Project Addition) {{{2
+" Keymaps: {{{2
 " =======
 
-" TODO: handle Vim9 script comments when something like #13104 is merged
-syn match  vimKeymapStart	"^"	contained skipwhite nextgroup=vimKeymapLhs,vimKeymapLineComment
+syn match  vimKeymapStart	"^"	contained skipwhite nextgroup=vimKeymapLhs,@vimKeymapLineComment
 syn match  vimKeymapLhs	"\S\+"	contained skipwhite nextgroup=vimKeymapRhs contains=vimNotation
 syn match  vimKeymapRhs	"\S\+"	contained skipwhite nextgroup=vimKeymapTailComment contains=vimNotation
 syn match  vimKeymapTailComment	"\S.*"	contained
-syn match  vimKeymapLineComment	+".*+	contained contains=@vimCommentGroup,vimCommentString,vimCommentTitle
+
+" TODO: remove when :" comment is matched in parts as "ex-colon comment" --djk
+if s:vim9script
+  syn match  vim9KeymapLineComment	"#.*"	contained contains=@vimCommentGroup,vimCommentString,vim9CommentTitle
+else
+  syn match  vimKeymapLineComment	+".*+	contained contains=@vimCommentGroup,vimCommentString,vimCommentTitle
+endif
+syn cluster vimKeymapLineComment contains=vim9\=KeymapLineComment
 
 syn region vimKeymap matchgroup=vimCommand start="\<loadk\%[eymap]\>" end="\%$" contains=vimKeymapStart
 
@@ -323,9 +331,10 @@ syn match	vimSpecFileMod	"\(:[phtre]\)\+"	contained
 
 " User-Specified Commands: {{{2
 " =======================
-syn cluster	vimUserCmdList	contains=@vimCmdList,vimCmplxRepeat,vimComment,vim9Comment,vimCtrlChar,vimEscapeBrace,vimFunc,vimNotation,vimNumber,vimOper,vimRegister,vimSpecFile,vimString,vimSubst,vimSubstRep,vimSubstRange
+syn cluster	vimUserCmdList	contains=@vimCmdList,vimCmplxRepeat,@vimComment,vimCtrlChar,vimEscapeBrace,vimFunc,vimNotation,vimNumber,vimOper,vimRegister,vimSpecFile,vimString,vimSubst,vimSubstRep,vimSubstRange
 syn keyword	vimUserCommand	contained	com[mand]
-syn match	vimUserCmd	"\<com\%[mand]!\=\>.*$"	contains=vimUserAttrb,vimUserAttrbError,vimUserCommand,@vimUserCmdList,vimComFilter
+syn match	vimUserCmdName	contained	"\<\u\w*\>" nextgroup=vimUserCmdBlock skipwhite
+syn match	vimUserCmd	"\<com\%[mand]!\=\>.*$"	contains=vimUserAttrb,vimUserAttrbError,vimUserCommand,@vimUserCmdList,vimComFilter,vimCmdBlock,vimUserCmdName
 syn match	vimUserAttrbError	contained	"-\a\+\ze\s"
 syn match	vimUserAttrb	contained	"-nargs=[01*?+]"	contains=vimUserAttrbKey,vimOper
 syn match	vimUserAttrb	contained	"-complete="		contains=vimUserAttrbKey,vimOper nextgroup=vimUserAttrbCmplt,vimUserCmdError
@@ -347,20 +356,41 @@ syn match	vimUserAttrbCmpltFunc contained	",\%([sS]:\|<[sS][iI][dD]>\)\=\%(\h\w*
 syn case match
 syn match	vimUserAttrbCmplt contained	"custom,\u\w*"
 
+syn region	vimUserCmdBlock	contained	matchgroup=vimSep start="{" end="}" contains=@vimDefBodyList
+
 " Lower Priority Comments: after some vim commands... {{{2
 " =======================
-syn match	vimComment	excludenl +\s"[^\-:.%#=*].*$+lc=1	contains=@vimCommentGroup,vimCommentString
-syn match	vimComment	+\<endif\s\+".*$+lc=5	contains=@vimCommentGroup,vimCommentString
-syn match	vimComment	+\<else\s\+".*$+lc=4	contains=@vimCommentGroup,vimCommentString
-syn region	vimCommentString	contained oneline start='\S\s\+"'ms=e	end='"'
-" Vim9 comments - TODO: might be highlighted while they don't work
-syn match	vim9Comment	excludenl +\s#[^{].*$+lc=1	contains=@vimCommentGroup,vimCommentString
-syn match	vim9Comment	+\<endif\s\+#[^{].*$+lc=5	contains=@vimCommentGroup,vimCommentString
-syn match	vim9Comment	+\<else\s\+#[^{].*$+lc=4	contains=@vimCommentGroup,vimCommentString
-" Vim9 comment inside expression
-syn match	vim9Comment	+\s\zs#[^{].*$+ms=s+1	contains=@vimCommentGroup,vimCommentString
-syn match	vim9Comment	+^\s*#[^{].*$+	contains=@vimCommentGroup,vimCommentString
-syn match	vim9Comment	+^\s*#$+	contains=@vimCommentGroup,vimCommentString
+syn region	vimCommentString	contained oneline start='\S\s\+"'ms=e end='"'
+
+if s:vim9script
+  syn match	vimComment	excludenl +\s"[^\-:.%#=*].*$+lc=1	contains=@vimCommentGroup,vimCommentString contained
+  syn match	vimComment	+\<endif\s\+".*$+lc=5	contains=@vimCommentGroup,vimCommentString contained
+  syn match	vimComment	+\<else\s\+".*$+lc=4	contains=@vimCommentGroup,vimCommentString contained
+  " Vim9 comments - TODO: might be highlighted while they don't work
+  syn match	vim9Comment	excludenl +\s#[^{].*$+lc=1	contains=@vimCommentGroup,vimCommentString
+  syn match	vim9Comment	+\<endif\s\+#[^{].*$+lc=5	contains=@vimCommentGroup,vimCommentString
+  syn match	vim9Comment	+\<else\s\+#[^{].*$+lc=4	contains=@vimCommentGroup,vimCommentString
+  " Vim9 comment inside expression
+  " syn match	vim9Comment	+\s\zs#[^{].*$+ms=s+1	contains=@vimCommentGroup,vimCommentString
+  " syn match	vim9Comment	+^\s*#[^{].*$+		contains=@vimCommentGroup,vimCommentString
+  " syn match	vim9Comment	+^\s*#$+		contains=@vimCommentGroup,vimCommentString
+
+  syn cluster vimComment contains=vim9Comment
+else
+  syn match	vimComment	excludenl +\s"[^\-:.%#=*].*$+lc=1	contains=@vimCommentGroup,vimCommentString
+  syn match	vimComment	+\<endif\s\+".*$+lc=5	contains=@vimCommentGroup,vimCommentString
+  syn match	vimComment	+\<else\s\+".*$+lc=4	contains=@vimCommentGroup,vimCommentString
+  " Vim9 comments - TODO: might be highlighted while they don't work
+  syn match	vim9Comment	excludenl +\s#[^{].*$+lc=1	contains=@vimCommentGroup,vimCommentString contained
+  syn match	vim9Comment	+\<endif\s\+#[^{].*$+lc=5	contains=@vimCommentGroup,vimCommentString contained
+  syn match	vim9Comment	+\<else\s\+#[^{].*$+lc=4	contains=@vimCommentGroup,vimCommentString contained
+  " Vim9 comment inside expression
+  syn match	vim9Comment	+\s\zs#[^{].*$+ms=s+1	contains=@vimCommentGroup,vimCommentString contained
+  syn match	vim9Comment	+^\s*#[^{].*$+		contains=@vimCommentGroup,vimCommentString contained
+  syn match	vim9Comment	+^\s*#$+		contains=@vimCommentGroup,vimCommentString contained
+
+  syn cluster vimComment contains=vimComment
+endif
 
 " Environment Variables: {{{2
 " =====================
@@ -450,7 +480,7 @@ syn match	vimCmplxRepeat	'[^a-zA-Z_/\\()]q[0-9a-zA-Z"]\>'lc=1
 syn match	vimCmplxRepeat	'@[0-9a-z".=@:]\ze\($\|[^a-zA-Z]\>\)'
 
 " Set command and associated set-options (vimOptions) with comment {{{2
-syn region	vimSet		matchgroup=vimCommand start="\<\%(setl\%[ocal]\|setg\%[lobal]\|se\%[t]\)\>" skip="\%(\\\\\)*\\.\n\@!" end="$" end="|" matchgroup=vimNotation end="<[cC][rR]>" keepend contains=vimSetEqual,vimOption,vimErrSetting,vimComment,vim9Comment,vimSetString,vimSetMod
+syn region	vimSet		matchgroup=vimCommand start="\<\%(setl\%[ocal]\|setg\%[lobal]\|se\%[t]\)\>" skip="\%(\\\\\)*\\.\n\@!" end="$" end="|" matchgroup=vimNotation end="<[cC][rR]>" keepend contains=vimSetEqual,vimOption,vimErrSetting,@vimComment,vimSetString,vimSetMod
 syn region	vimSetEqual	contained	start="[=:]\|[-+^]=" skip="\\\\\|\\\s" end="[| \t]"me=e-1 end="$"	contains=vimCtrlChar,vimSetSep,vimNotation,vimEnvvar
 syn region	vimSetString	contained	start=+="+hs=s+1	skip=+\\\\\|\\"+  end=+"+		contains=vimCtrlChar
 syn match	vimSetSep	contained	"[,:]"
@@ -482,9 +512,10 @@ syn keyword	vimFor	for	skipwhite nextgroup=vimVar,vimVarList
 " =======
 syn match	vimAutoEventList	contained	"\(!\s\+\)\=\(\a\+,\)*\a\+"	contains=vimAutoEvent nextgroup=vimAutoCmdSpace
 syn match	vimAutoCmdSpace	contained	"\s\+"	nextgroup=vimAutoCmdSfxList
-syn match	vimAutoCmdSfxList	contained	"\S*"	skipwhite nextgroup=vimAutoCmdMod
+syn match	vimAutoCmdSfxList	contained	"\S*"	skipwhite nextgroup=vimAutoCmdMod,vimAutoCmdBlock
 syn keyword	vimAutoCmd	au[tocmd] do[autocmd] doautoa[ll]	skipwhite nextgroup=vimAutoEventList
-syn match	vimAutoCmdMod	"\(++\)\=\(once\|nested\)"
+syn match	vimAutoCmdMod	"\(++\)\=\(once\|nested\)"	skipwhite nextgroup=vimAutoCmdBlock
+syn region	vimAutoCmdBlock	contained	matchgroup=vimSep start="{" end="}" contains=@vimDefBodyList
 
 " Echo And Execute: -- prefer strings! {{{2
 " ================
@@ -624,7 +655,7 @@ if has("conceal")
  syn match	vimSynCcharValue	contained	"\S"
 endif
 
-syn match	vimSyntax	"\<sy\%[ntax]\>"	contains=vimCommand skipwhite nextgroup=vimSynType,vimComment,vim9Comment
+syn match	vimSyntax	"\<sy\%[ntax]\>"	contains=vimCommand skipwhite nextgroup=vimSynType,@vimComment
 syn cluster vimFuncBodyList add=vimSyntax
 
 " Syntax: case {{{2
@@ -713,7 +744,7 @@ syn match	vimIsCommand	"<Bar>\s*\a\+"	transparent contains=vimCommand,vimNotatio
 
 " Highlighting: {{{2
 " ============
-syn cluster	vimHighlightCluster		contains=vimHiLink,vimHiClear,vimHiKeyList,vimComment,vim9Comment
+syn cluster	vimHighlightCluster		contains=vimHiLink,vimHiClear,vimHiKeyList,@vimComment
 if !exists("g:vimsyn_noerror") && !exists("g:vimsyn_novimhictermerror")
  syn match	vimHiCtermError	contained	"\D\i*"
 endif
@@ -769,16 +800,21 @@ syn match	vimCtrlChar	"[
--]"
 
 " Beginners - Patterns that involve ^ {{{2
 " =========
-syn match	vimLineComment	+^[ \t:]*".*$+	contains=@vimCommentGroup,vimCommentString,vimCommentTitle,vimComment
-syn match	vimLineComment	+^[ \t:]*"\("[^"]*"\|[^"]\)*$+	contains=@vimCommentGroup,vimCommentString,vimCommentTitle
-syn match	vim9LineComment	+^[ \t:]\+#.*$+	contains=@vimCommentGroup,vimCommentString,vimCommentTitle
+if s:vim9script
+  syn match	vimLineComment	+^[ \t:]*".*$+	contains=@vimCommentGroup,vimCommentString,vimCommentTitle contained
+  syn match	vim9LineComment	+^[ \t:]*#.*$+	contains=@vimCommentGroup,vimCommentString,vim9CommentTitle
+else
+  syn match	vimLineComment	+^[ \t:]*".*$+	contains=@vimCommentGroup,vimCommentString,vimCommentTitle
+  syn match	vim9LineComment	+^[ \t:]*#.*$+	contains=@vimCommentGroup,vimCommentString,vim9CommentTitle contained
+endif
 syn match	vimCommentTitle	'"\s*\%([sS]:\|\h\w*#\)\=\u\w*\(\s\+\u\w*\)*:'hs=s+1	contained contains=vimCommentTitleLeader,vimTodo,@vimCommentGroup
-" Note: Look-behind to work around nextgroup skipnl consuming leading whitespace and preventing a match
+syn match	vim9CommentTitle	'#\s*\%([sS]:\|\h\w*#\)\=\u\w*\(\s\+\u\w*\)*:'hs=s+1	contained contains=vim9CommentTitleLeader,vimTodo,@vimCommentGroup
 syn match	vimContinue		"^\s*\zs\\"
 syn match         vimContinueComment	'^\s*\zs["#]\\ .*' contained
 syn cluster	vimContinue contains=vimContinue,vimContinueComment
 syn region	vimString	start="^\s*\\\z(['"]\)" skip='\\\\\|\\\z1' end="\z1" oneline keepend contains=@vimStringGroup,vimContinue
 syn match	vimCommentTitleLeader	'"\s\+'ms=s+1	contained
+syn match	vim9CommentTitleLeader	'#\s\+'ms=s+1	contained
 
 " Searches And Globals: {{{2
 " ====================
@@ -787,6 +823,17 @@ syn match	vimSearchDelim	'^\s*\zs[/?]\|[/?]$'	contained
 syn region	vimGlobal	matchgroup=Statement start='\<g\%[lobal]!\=/'  skip='\\.' end='/'	skipwhite nextgroup=vimSubst1
 syn region	vimGlobal	matchgroup=Statement start='\<v\%[global]!\=/' skip='\\.' end='/'	skipwhite nextgroup=vimSubst1
 
+" Vim9 Script Regions: {{{2
+" ==================
+
+if s:vim9script
+  syn cluster vimLegacyTop contains=TOP,vimPreVim9script,vim9Comment,vim9LineComment
+  syn region vimPreVim9script start="\%^" end="^\ze\s*vim9s\%[cript]\>" contains=@vimLegacyTop,vimComment,vimLineComment
+
+  syn keyword vim9ScriptArg noclear
+  syn keyword vimCommand vim9s[cript] nextgroup=vim9ScriptArg skipwhite
+endif
+
 " Embedded Scripts:  {{{2
 " ================
 "   perl,ruby     : Benoit Cerrina
@@ -994,6 +1041,7 @@ if !exists("skip_vim_syntax_inits")
   hi def link vimBufnrWarn	vimWarn
  endif
 
+ hi def link vim9ScriptArg	Special
  hi def link vimAbb	vimCommand
  hi def link vimAddress	vimMark
  hi def link vimAugroupBang	vimBang
@@ -1013,6 +1061,7 @@ if !exists("skip_vim_syntax_inits")
  hi def link vim9Comment	Comment
  hi def link vimCommentString	vimString
  hi def link vimCommentTitle	PreProc
+ hi def link vim9CommentTitle	PreProc
  hi def link vimCondHL	vimCommand
  hi def link vimConst	vimCommand
  hi def link vimContinue	Special
@@ -1070,6 +1119,7 @@ if !exists("skip_vim_syntax_inits")
  hi def link vimHLGroup	vimGroup
  hi def link vimInsert	vimString
  hi def link vimIskSep	Delimiter
+ hi def link vim9KeymapLineComment	vimKeymapLineComment
  hi def link vimKeymapLineComment	vimComment
  hi def link vimKeymapTailComment	vimComment
  hi def link vimLet	vimCommand
@@ -1192,5 +1242,5 @@ delc VimFoldP
 delc VimFoldr
 delc VimFoldt
 let &cpo = s:keepcpo
-unlet s:keepcpo
+unlet s:keepcpo s:vim9script
 " vim:ts=18 fdm=marker ft=vim
diff --git a/runtime/syntax/testdir/dumps/vim9_keymap_00.dump b/runtime/syntax/testdir/dumps/vim9_keymap_00.dump
new file mode 100644
index 0000000000..d1bc96cfd8
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_keymap_00.dump
@@ -0,0 +1,20 @@
+>v+0#af5f00255#ffffff0|i|m|9|s|c|r|i|p|t| +0#0000000&@64
+@75
+|#+0#0000e05&| |V|i|m| |K|e|y|m|a|p| |f|i|l|e| |f|o|r| |s|y|n|t|a|x| |t|e|s|t|i|n|g| +0#0000000&@38
+@75
+|s+0#af5f00255&|c|r|i|p|t|e|n|c|o|d|i|n|g| +0#0000000&|u|t|f|-+0#af5f00255&|8+0#e000002&| +0#0000000&@54
+@75
+|l+0#af5f00255&|e|t| +0#0000000&|b+0#00e0e07&|:|k|e|y|m|a|p|_|n|a|m|e| +0#0000000&|=+0#af5f00255&| +0#0000000&|"+0#e000002&|s|y|n|t|a|x|-|t|e|s|t|"| +0#0000000&@41
+@75
+|l+0#af5f00255&|o|a|d|k|e|y|m|a|p| +0#0000000&@64
+@75
+|#+0#0000e05&| |L|i|n|e| |c|o|m@1|e|n|t| +0#0000000&@60
+@75
+@2|#+0#0000e05&| |A|n|o|t|h|e|r| |l|i|n|e| |c|o|m@1|e|n|t| +0#0000000&@50
+@75
+|a| |A| @3|B+0#0000e05&|a|s|i|c| |m|a|p@1|i|n|g| +0#0000000&@54
+|'|a| |á| @2|M+0#0000e05&|o|r|e| |t|h|a|n| |o|n|e| |c|h|a|r| |i|n| |f|i|r|s|t| |c|o|l|u|m|n| +0#0000000&@33
+@75
+|#+0#0000e05&| |S|p|e|c|i|a|l| |n|o|t|a|t|i|o|n| +0#0000000&@56
+|<+0#e000e06&|c|h|a|r|-|6|2|>| +0#0000000&@5|B| @14|S+0#0000e05&|p|e|c|i|a|l| |n|o|t|a|t|i|o|n| |a|l@1|o|w|e|d| |i|n| |L|H|S| |-| |d|e|c|i|m|a|l| +0#0000000&@2
+@57|1|,|1| @10|T|o|p| 
diff --git a/runtime/syntax/testdir/dumps/vim9_keymap_01.dump b/runtime/syntax/testdir/dumps/vim9_keymap_01.dump
new file mode 100644
index 0000000000..1d0823fe61
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_keymap_01.dump
@@ -0,0 +1,20 @@
+| +0&#ffffff0@74
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new file mode 100644
index 0000000000..8afcbba81b
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_keymap_99.dump
@@ -0,0 +1,20 @@
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diff --git a/runtime/syntax/testdir/dumps/vim9_legacy_header_00.dump b/runtime/syntax/testdir/dumps/vim9_legacy_header_00.dump
new file mode 100644
index 0000000000..2f682d960b
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_legacy_header_00.dump
@@ -0,0 +1,20 @@
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diff --git a/runtime/syntax/testdir/dumps/vim9_legacy_header_99.dump b/runtime/syntax/testdir/dumps/vim9_legacy_header_99.dump
new file mode 100644
index 0000000000..d400e3166d
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_legacy_header_99.dump
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diff --git a/runtime/syntax/testdir/dumps/vim_00.dump b/runtime/syntax/testdir/dumps/vim_00.dump
new file mode 100644
index 0000000000..852148f1f4
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_00.dump
@@ -0,0 +1,20 @@
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diff --git a/runtime/syntax/testdir/dumps/vim_99.dump b/runtime/syntax/testdir/dumps/vim_99.dump
new file mode 100644
index 0000000000..8e9320cc92
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_99.dump
@@ -0,0 +1,20 @@
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diff --git a/runtime/syntax/testdir/dumps/vim_ex_commands_31.dump b/runtime/syntax/testdir/dumps/vim_ex_commands_31.dump
index 07075f7d45..3711988d69 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_commands_31.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_commands_31.dump
@@ -5,7 +5,7 @@
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diff --git a/runtime/syntax/testdir/dumps/vim_ex_commands_64.dump b/runtime/syntax/testdir/dumps/vim_ex_commands_64.dump
index 5561d991de..bf3df8d628 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_commands_64.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_commands_64.dump
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diff --git a/runtime/syntax/testdir/dumps/vim_ex_comment-vim9_00.dump b/runtime/syntax/testdir/dumps/vim_ex_comment-vim9_00.dump
new file mode 100644
index 0000000000..57b021621b
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_comment-vim9_00.dump
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diff --git a/runtim