From 2a6be835122d906c6ec10682c2a771b25c87c611 Mon Sep 17 00:00:00 2001
From: Doug Kearns <dougkearns@gmail.com>
Date: Thu, 3 Apr 2025 21:39:24 +0200
Subject: [PATCH] runtime(vim): Update base-syntax, improve :set backslash
 handling

Improve backslash handling in :set option values. There is no special
handling for options supporting Windows path separators yet.

See :help option-backslash.

Remove the vimSetString syntax group. Option string values cannot be
specified with a quoted string, this is a command terminating tail
comment.

fixes: #16913
closes: #17034

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
---
 runtime/syntax/generator/vim.vim.base         | 29 +++++--
 .../syntax/testdir/dumps/vim_ex_set_01.dump   |  2 +-
 .../syntax/testdir/dumps/vim_ex_set_02.dump   |  2 +-
 .../syntax/testdir/dumps/vim_ex_set_03.dump   |  2 +-
 .../syntax/testdir/dumps/vim_ex_set_04.dump   |  2 +-
 .../syntax/testdir/dumps/vim_ex_set_05.dump   |  4 +-
 .../syntax/testdir/dumps/vim_ex_set_06.dump   | 18 ++---
 .../syntax/testdir/dumps/vim_ex_set_07.dump   | 20 +++++
 .../dumps/vim_ex_set_backslash_00.dump        | 20 +++++
 .../dumps/vim_ex_set_backslash_01.dump        | 20 +++++
 .../dumps/vim_ex_set_backslash_02.dump        | 20 +++++
 .../dumps/vim_ex_set_backslash_03.dump        | 20 +++++
 .../dumps/vim_ex_set_backslash_04.dump        | 20 +++++
 runtime/syntax/testdir/input/vim_ex_set.vim   | 13 ++-
 .../testdir/input/vim_ex_set_backslash.vim    | 79 +++++++++++++++++++
 runtime/syntax/vim.vim                        | 29 +++++--
 16 files changed, 274 insertions(+), 26 deletions(-)
 create mode 100644 runtime/syntax/testdir/dumps/vim_ex_set_07.dump
 create mode 100644 runtime/syntax/testdir/dumps/vim_ex_set_backslash_00.dump
 create mode 100644 runtime/syntax/testdir/dumps/vim_ex_set_backslash_01.dump
 create mode 100644 runtime/syntax/testdir/dumps/vim_ex_set_backslash_02.dump
 create mode 100644 runtime/syntax/testdir/dumps/vim_ex_set_backslash_03.dump
 create mode 100644 runtime/syntax/testdir/dumps/vim_ex_set_backslash_04.dump
 create mode 100644 runtime/syntax/testdir/input/vim_ex_set_backslash.vim

diff --git a/runtime/syntax/generator/vim.vim.base b/runtime/syntax/generator/vim.vim.base
index 78abaf5a97..aa868e9f01 100644
--- a/runtime/syntax/generator/vim.vim.base
+++ b/runtime/syntax/generator/vim.vim.base
@@ -2,7 +2,7 @@
 " Language:	   Vim script
 " Maintainer:	   Hirohito Higashi <h.east.727 ATMARK gmail.com>
 "	   Doug Kearns <dougkearns@gmail.com>
-" Last Change:	   2025 Mar 29
+" Last Change:	   2025 Apr 03
 " Former Maintainer: Charles E. Campbell
 
 " DO NOT CHANGE DIRECTLY.
@@ -771,12 +771,31 @@ syn match	vimCmplxRepeat	'@[0-9a-z".=@:]\ze\($\|[^a-zA-Z]\>\)'
 
 " Set command and associated set-options (vimOptions) with comment {{{2
 syn match	vimSet		"\<\%(setl\%[ocal]\|setg\%[lobal]\|se\%[t]\)\>" skipwhite nextgroup=vimSetBang,vimSetArgs
-syn region	vimSetArgs	contained	start="\S" skip=+\\|\|\n\s*\\\|\n\s*["#]\\ + matchgroup=vimCmdSep end="|" end="$" matchgroup=vimNotation end="<[cC][rR]>" keepend contains=@vimComment,@vimContinue,vimErrSetting,vimOption,vimSetAll,vimSetTermcap
-syn region	vimSetEqual	contained	matchgroup=vimOper start="[=:]\|[-+^]=" skip=+\\|\|\\\s\|\n\s*\\\|\n\s*["#]\\ \|^\s*\\\|^\s*["#]\\ + matchgroup=vimCmdSep end="|" end="\ze\s" end="$" contains=@vimContinue,vimCtrlChar,vimEnvvar,vimNotation,vimSetSep
+syn region	vimSetComment	contained	start=+"+ skip=+\n\s*\%(\\\||"\\ \)+ end="$" contains=@vimCommentGroup,vimCommentString extend
+syn match	vimSetCmdSep	contained	"|" skipwhite nextgroup=@vimCmdList,vimSubst1,vimFunc
+syn match	vimSetEscape	contained	"\\\%(\\[|"]\|.\)"
+syn match	vimSetBarEscape	contained	"\\|"
+syn match	vimSetQuoteEscape	contained	+\\"+
+syn region	vimSetArgs	contained
+      \ start="\S"
+      \ skip=+\n\s*\%(\\\|["#]\\ \)\|^\s*"\\ +
+      \ end=+\ze\\\@1<![|"]+
+      "\ assume this isn't an escaped char with backslash on the previous line
+      \ end=+^\s*\\\ze[|"]+
+      \ end="\ze\s#"
+      \ end="$"
+      \ nextgroup=vimSetCmdSep,vimSetComment,vim9Comment
+      \ contains=@vimContinue,vimErrSetting,vimOption,vimSetAll,vimSetTermcap
+      \ keepend
+syn region	vimSetEqual	contained
+      \ matchgroup=vimOper
+      \ start="[=:]\|[-+^]="
+      \ skip=+\\\s\|^\s*\%(\\\|["#]\\ \)+
+      \ end="\ze\s"
+      \ contains=@vimContinue,vimCtrlChar,vimEnvvar,vimNotation,vimSetSep,vimSetEscape,vimSetBarEscape,vimSetQuoteEscape
 syn match	vimSetBang	contained	"\a\@1<=!" skipwhite nextgroup=vimSetAll,vimSetTermcap
 syn keyword	vimSetAll	contained	all nextgroup=vimSetMod
 syn keyword	vimSetTermcap	contained	termcap
-syn region	vimSetString	contained	start=+="+hs=s+1	skip=+\\\\\|\\"+  end=+"+	contains=vimCtrlChar
 syn match	vimSetSep	contained	"[,:]"
 syn match	vimSetMod	contained	"\a\@1<=\%(&vim\=\|[!&?<]\)"
 
@@ -1624,9 +1643,9 @@ if !exists("skip_vim_syntax_inits")
  hi def link vimSet	vimCommand
  hi def link vimSetAll	vimOption
  hi def link vimSetBang	vimBang
+ hi def link vimSetComment	vimComment
  hi def link vimSetMod	vimOption
  hi def link vimSetSep	vimSep
- hi def link vimSetString	vimString
  hi def link vimSetTermcap	vimOption
  hi def link vimShebang	PreProc
  hi def link vimSleep	vimCommand
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_01.dump b/runtime/syntax/testdir/dumps/vim_ex_set_01.dump
index 6c1421ae2b..90c52e1e5b 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_set_01.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_01.dump
@@ -17,4 +17,4 @@
 |s+0#af5f00255&|e|t| +0#0000000&|a+0#e000e06&|l|e|p|h|++0#af5f00255&|=|9+0#0000000&|6| @61
 |s+0#af5f00255&|e|t| +0#0000000&|a+0#e000e06&|l|e|p|h|^+0#af5f00255&|=|2+0#0000000&| @62
 |s+0#af5f00255&|e|t| +0#0000000&|a+0#e000e06&|l|e|p|h|-+0#af5f00255&|=|9+0#0000000&|6| @61
-@57|1|9|,|1| @9|1|3|%| 
+@57|1|9|,|1| @9|1|2|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_02.dump b/runtime/syntax/testdir/dumps/vim_ex_set_02.dump
index 0765de0c8e..e8ef891d1f 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_set_02.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_02.dump
@@ -17,4 +17,4 @@
 |"+0#0000e05&| |:|h|e|l|p| |o|p|t|i|o|n|-|b|a|c|k|s|l|a|s|h| +0#0000000&@50
 @75
 |"+0#0000e05&| |W|h|e|n| |s|e|t@1|i|n|g| |o|p|t|i|o|n|s| |u|s|i|n|g| |||:|l|e|t||| |a|n|d| |||l|i|t|e|r|a|l|-|s|t|r|i|n|g|||,| |y|o|u| |n|e@1|d| |t|o| |u|s|@+0#4040ff13&@2
-| +0#0000000&@56|3|7|,|0|-|1| @7|3|2|%| 
+| +0#0000000&@56|3|7|,|0|-|1| @7|2|9|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_03.dump b/runtime/syntax/testdir/dumps/vim_ex_set_03.dump
index 5d2285ff4f..cad9c9d54f 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_set_03.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_03.dump
@@ -17,4 +17,4 @@
 |"+0#0000e05&| |T|h|i|s| |e|x|a|m|p|l|e| |s|e|t|s| |t|h|e| |'|t|i|t|l|e|s|t|r|i|n|g|'| |o|p|t|i|o|n| |t|o| |"+0#e000002&|h|i|||t|h|e|r|e|"|:+0#0000e05&| +0#0000000&@15
 |s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|h+0#0000000&|i|\|||t|h|e|r|e| @49
 |"+0#0000e05&| |T|h|i|s| |s|e|t|s| |t|h|e| |'|t|i|t|l|e|s|t|r|i|n|g|'| |o|p|t|i|o|n| |t|o| |"+0#e000002&|h|i|"| +0#0000e05&|a|n|d| |'|i|c|o|n|s|t|r|i|n|g|'| |t|o| |"+0#e000002&|t|h|e|r|e|"|:+0#0000e05&| +0#0000000&@1
-@57|5|4|,|1| @9|5|1|%| 
+@57|5|4|,|1| @9|4|6|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_04.dump b/runtime/syntax/testdir/dumps/vim_ex_set_04.dump
index e2b6b9d263..101a1e0ca2 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_set_04.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_04.dump
@@ -17,4 +17,4 @@
 |s+0#af5f00255&|e|t| +0#0000000&|p+0#e000e06&|a|t|h|=+0#af5f00255&|a+0#0000000&|b|c|,+0#e000e06&|d+0#0000000&|e|f|,+0#e000e06&|g+0#0000000&|h|i| @54
 @6|"+0#0000e05&|\| |d|e|f| |i|s| |t|h|e| |'|d|e|f|i|n|e|'| |o|p|t|i|o|n| +0#0000000&@39
 @6|\+0#e000e06&| +0#0000000&|d+0#e000e06&|e|f|=+0#af5f00255&|a+0#0000000&|b|c|,+0#e000e06&|d+0#0000000&|e|f|,+0#e000e06&|g+0#0000000&|h|i| @51
-@57|7|2|,|1| @9|7|0|%| 
+@57|7|2|,|1| @9|6|2|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_05.dump b/runtime/syntax/testdir/dumps/vim_ex_set_05.dump
index fcc8be4d62..0992fe4eb6 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_set_05.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_05.dump
@@ -9,7 +9,7 @@
 @6|\+0#e000e06&|a+0#0000000&|b|c|,+0#e000e06&|d+0#0000000&|e|f| @60
 @75
 @75
-|"+0#0000e05&| |C|o|m|p|i|l|e|r|S|e|t| +0#0000000&@61
+|"+0#0000e05&| |:|C|o|m|p|i|l|e|r|S|e|t| +0#0000000&@60
 @75
 |C+0#af5f00255&|o|m|p|i|l|e|r|S|e|t| +0#0000000&|m+0#e000e06&|a|k|e|p|r|g|=+0#af5f00255&|a+0#0000000&|n|t| @51
 |C+0#af5f00255&|o|m|p|i|l|e|r|S|e|t| +0#0000000&|e+0#e000e06&|r@1|o|r|f|o|r|m|a|t|=+0#af5f00255&|\+0#0000000&| |%|#|[|%|.|%|#|]|\| |%|#|%|f|:+0#e000e06&|%+0#0000000&|l|:+0#e000e06&|%+0#0000000&|v|:+0#e000e06&|%+0#0000000&|*|\@1|d|:+0#e000e06&|%+0#0000000&|*|\@1|d|:+0#e000e06&|\+0#0000000&| |%|t|%|[|%|^|:+0#e000e06&|]+0#0000000&|%|#|:+0#e000e06&|%+0#0000000&|m|,+0#e000e06&
@@ -17,4 +17,4 @@
 @75
 @75
 |"+0#0000e05&| |U|n|r|e|p|o|r|t|e|d| |i|s@1|u|e| |(|d|o|u|b|l|e| |b|a|c|k|s|l|a|s|h|)| +0#0000000&@37
-@57|9|0|,|0|-|1| @7|8|9|%| 
+@57|9|0|,|0|-|1| @7|8|0|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_06.dump b/runtime/syntax/testdir/dumps/vim_ex_set_06.dump
index 8807faff9b..3179e76d99 100644
--- a/runtime/syntax/testdir/dumps/vim_ex_set_06.dump
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_06.dump
@@ -9,12 +9,12 @@
 |s+0#af5f00255&|e|t| +0#0000000&|q+0#e000e06&|u|o|t|e@1|s|c|a|p|e|=+0#af5f00255&|\+0#0000000&| @57
 |e+0#af5f00255&|c|h|o| +0#0000000&|"+0#e000002&|F|o@1|"| +0#0000000&@64
 @75
-|~+0#4040ff13&| @73
-|~| @73
-|~| @73
-|~| @73
-|~| @73
-|~| @73
-|~| @73
-|~| @73
-| +0#0000000&@56|1|0|8|,|1| @8|B|o|t| 
+@75
+|"+0#0000e05&| |I|s@1|u|e| |#|1|6|9|1|3| |(|v|i|m| |s|y|n|t|a|x|:| |s|e|t| |l|a|n|g|m|a|p| |m|a|y| |h|a|v|e| |w|r|o|n|g| |h|i|g|h|l|i|g|h|t|)| +0#0000000&@9
+@75
+|s+0#af5f00255&|e|t| +0#0000000&|l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Ф+0#0000000&|Ы|В|А|П|Р|О|Л|Д|Ж|Э|Ё|;|A|S|D|F|G|H|J|K|L|\@1|:+0#e000e06&|\+0#0000000&@1|"|\@1||| @30
+|s+0#af5f00255&|e|t| +0#0000000&|l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Я+0#0000000&|Ч|С|М|И|Т|Ь|Б|Ю|;|Z|X|C|V|B|N|M|<+0#e000e06&|>| +0#0000000&@42
+@75
+|s+0#af5f00255&|e|t| +0#0000000&|l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Ф+0#0000000&|Ы|В|А|П|Р|О|Л|Д|Ж|Э|Ё|;|A|S|D|F|G|H|J|K|L|\@1|:+0#e000e06&|\+0#0000000&@1|"|\@1||| @30
+@6|\+0#e000e06&| +0#0000000&|l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Я+0#0000000&|Ч|С|М|И|Т|Ь|Б|Ю|;|Z|X|C|V|B|N|M|<+0#e000e06&|>| +0#0000000&@38
+@57|1|0|8|,|1| @8|9|7|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_07.dump b/runtime/syntax/testdir/dumps/vim_ex_set_07.dump
new file mode 100644
index 0000000000..ef2b99c9cf
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_07.dump
@@ -0,0 +1,20 @@
+| +0&#ffffff0@5|\+0#e000e06&| +0#0000000&|l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Я+0#0000000&|Ч|С|М|И|Т|Ь|Б|Ю|;|Z|X|C|V|B|N|M|<+0#e000e06&|>| +0#0000000&@38
+@75
+|s+0#af5f00255&|e|t| +0#0000000&|l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Ф+0#0000000&|Ы|В|А|П|Р|О|Л|Д|Ж|Э|Ё|;|A|S|D|F|G|H|J|K|L|\@1|:+0#e000e06&|\+0#0000000&@1|"|\@1||| |l+0#e000e06&|a|n|g|m|a|p|++0#af5f00255&|=|Я+0#0000000&|Ч|С|М|И|Т|Ь|Б|Ю|;|Z|X|C|V|B|N|M|<+0#e000e06&|>| +0#0000000&@1
+> @74
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|2|4|,|0|-|1| @6|B|o|t| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_backslash_00.dump b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_00.dump
new file mode 100644
index 0000000000..9b7370db86
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_00.dump
@@ -0,0 +1,20 @@
+>"+0#0000e05#ffffff0| |V|i|m| |:|s|e|t| |c|o|m@1|a|n|d| |(|e|s|c|a|p|e|d| |c|h|a|r|a|c|t|e|r|s|)| +0#0000000&@35
+|"+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |h|i| |l|i|n|k| |v|i|m|S|e|t|E|s|c|a|p|e| @5|D|i|f@1|A|d@1| +0#0000000&@24
+|"+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |h|i| |l|i|n|k| |v|i|m|S|e|t|B|a|r|E|s|c|a|p|e| @2|D|i|f@1|D|e|l|e|t|e| +0#0000000&@21
+|"+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |h|i| |l|i|n|k| |v|i|m|S|e|t|Q|u|o|t|e|E|s|c|a|p|e| |D|i|f@1|D|e|l|e|t|e| +0#0000000&@21
+|"+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |h|i| |l|i|n|k| |v|i|m|S|e|t|E|q|u|a|l| @6|D|i|f@1|C|h|a|n|g|e| +0#0000000&@21
+@75
+@75
+|e+0#af5f00255&|c|h|o| +0#0000000&|"+0#e000002&|-@1| |1| |-@1|"| +0#0000000&@60
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255|a|f+0&#ffd7ff255|o@1|\+0&#5fd7ff255|a|b+0&#ffd7ff255|a|r|\+0&#5fd7ff255|a| +0&#ffffff0|"+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@36
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255|a|f+0&#ffd7ff255|o@1|\+0&#5fd7ff255|a|b+0&#ffd7ff255|a|r|\+0&#5fd7ff255|a| +0&#ffffff0@46
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255| |f+0&#ffd7ff255|o@1|\+0&#5fd7ff255| |b+0&#ffd7ff255|a|r|\+0&#5fd7ff255| | +0&#ffffff0|"+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@36
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255| |f+0&#ffd7ff255|o@1|\+0&#5fd7ff255| |b+0&#ffd7ff255|a|r|\+0&#5fd7ff255| | +0&#ffffff0@46
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#4040ff13#afffff255|||f+0#0000000#ffd7ff255|o@1|\+0#4040ff13#afffff255|||b+0#0000000#ffd7ff255|a|r|\+0#4040ff13#afffff255||| +0#0000000#ffffff0|"+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@36
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
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+@57|1|,|1| @10|T|o|p| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_backslash_01.dump b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_01.dump
new file mode 100644
index 0000000000..c99a3a6f4e
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_01.dump
@@ -0,0 +1,20 @@
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+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+@57|1|9|,|1| @9|2|1|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_backslash_02.dump b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_02.dump
new file mode 100644
index 0000000000..4250195d6c
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_02.dump
@@ -0,0 +1,20 @@
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+@75
+|e+0#af5f00255&|c|h|o| +0#0000000&|"+0#e000002&|-@1| |3| |-@1|"| +0#0000000&@60
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+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@2|a|f+0&#ffd7ff255|o@1|\+0&#5fd7ff255@2|a|b+0&#ffd7ff255|a|r|\+0&#5fd7ff255@2|a| +0&#ffffff0@40
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@2| |f+0&#ffd7ff255|o@1|\+0&#5fd7ff255@2| |b+0&#ffd7ff255|a|r|\+0&#5fd7ff255@2| | +0&#ffffff0|"+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@30
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+@57|3|7|,|1| @9|5|1|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_backslash_03.dump b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_03.dump
new file mode 100644
index 0000000000..f0f1662db0
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_03.dump
@@ -0,0 +1,20 @@
+|e+0#af5f00255#ffffff0|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
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+>s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@1|\+0#4040ff13#afffff255|||f+0#0000000#ffd7ff255|o@1|\+0&#5fd7ff255@1|\+0#4040ff13#afffff255|||b+0#0000000#ffd7ff255|a|r|\+0&#5fd7ff255@1|\+0#4040ff13#afffff255||| +0#0000000#ffffff0@40
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+@75
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+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@3|a+0&#ffd7ff255|f|o@1|\+0&#5fd7ff255@3|a+0&#ffd7ff255|b|a|r|\+0&#5fd7ff255@3|a+0&#ffd7ff255| +0&#ffffff0@37
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@3| +0&#ffffff0|f|o@1|\@3| |b|a|r|\@3| @1|"+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@27
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+@57|5@1|,|1| @9|8|1|%| 
diff --git a/runtime/syntax/testdir/dumps/vim_ex_set_backslash_04.dump b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_04.dump
new file mode 100644
index 0000000000..04e6eadc5d
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim_ex_set_backslash_04.dump
@@ -0,0 +1,20 @@
+|e+0#af5f00255#ffffff0|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@3| +0&#ffffff0|f|o@1|\@3| |b|a|r|\@3| @38
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@3|||f+0&#ffd7ff255|o@1|\+0&#5fd7ff255@3|||b+0&#ffd7ff255|a|r|\+0&#5fd7ff255@3||| +0&#ffffff0|"+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@27
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+>s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|\+0#0000000#5fd7ff255@3|||f+0&#ffd7ff255|o@1|\+0&#5fd7ff255@3|||b+0&#ffd7ff255|a|r|\+0&#5fd7ff255@3||| +0&#ffffff0@37
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+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+|s+0#af5f00255&|e|t| +0#0000000&|t+0#e000e06&|i|t|l|e|s|t|r|i|n|g|=+0#af5f00255&|f+0#0000000#ffd7ff255|o@1|\+0&#5fd7ff255@3|"|\@3|"|b+0&#ffd7ff255|a|r|\+0&#5fd7ff255@3|"| +0&#ffffff0@37
+|e+0#af5f00255&|c|h|o| +0#0000000&|&+0#00e0e07&|t|i|t|l|e|s|t|r|i|n|g| +0#0000000&@57
+@75
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|7|3|,|1| @9|B|o|t| 
diff --git a/runtime/syntax/testdir/input/vim_ex_set.vim b/runtime/syntax/testdir/input/vim_ex_set.vim
index 0b1d0101a4..e1bfc0f9c2 100644
--- a/runtime/syntax/testdir/input/vim_ex_set.vim
+++ b/runtime/syntax/testdir/input/vim_ex_set.vim
@@ -93,7 +93,7 @@ set path=
       \abc,def
 
 
-" CompilerSet
+" :CompilerSet
 
 CompilerSet makeprg=ant
 CompilerSet errorformat=\ %#[%.%#]\ %#%f:%l:%v:%*\\d:%*\\d:\ %t%[%^:]%#:%m,
@@ -111,3 +111,14 @@ echo "Foo"
 set quoteescape=\
 echo "Foo"
 
+
+" Issue #16913 (vim syntax: set langmap may have wrong highlight)
+
+set langmap+=ФЫВАПРОЛДЖЭЁ;ASDFGHJKL\\:\\"\\|
+set langmap+=ЯЧСМИТЬБЮ;ZXCVBNM<>
+
+set langmap+=ФЫВАПРОЛДЖЭЁ;ASDFGHJKL\\:\\"\\|
+      \ langmap+=ЯЧСМИТЬБЮ;ZXCVBNM<>
+
+set langmap+=ФЫВАПРОЛДЖЭЁ;ASDFGHJKL\\:\\"\\| langmap+=ЯЧСМИТЬБЮ;ZXCVBNM<>
+
diff --git a/runtime/syntax/testdir/input/vim_ex_set_backslash.vim b/runtime/syntax/testdir/input/vim_ex_set_backslash.vim
new file mode 100644
index 0000000000..53851a7693
--- /dev/null
+++ b/runtime/syntax/testdir/input/vim_ex_set_backslash.vim
@@ -0,0 +1,79 @@
+" Vim :set command (escaped characters)
+" VIM_TEST_SETUP hi link vimSetEscape      DiffAdd
+" VIM_TEST_SETUP hi link vimSetBarEscape   DiffDelete
+" VIM_TEST_SETUP hi link vimSetQuoteEscape DiffDelete
+" VIM_TEST_SETUP hi link vimSetEqual       DiffChange
+
+
+echo "-- 1 --"
+set titlestring=\afoo\abar\a " comment
+echo &titlestring
+set titlestring=\afoo\abar\a
+echo &titlestring
+set titlestring=\ foo\ bar\  " comment
+echo &titlestring
+set titlestring=\ foo\ bar\ 
+echo &titlestring
+set titlestring=\|foo\|bar\| " comment
+echo &titlestring
+set titlestring=\|foo\|bar\|
+echo &titlestring
+set titlestring=\"foo\"bar\" " comment
+echo &titlestring
+set titlestring=\"foo\"bar\"
+echo &titlestring
+
+echo "-- 2 --"
+set titlestring=\\afoo\\abar\\a " comment
+echo &titlestring
+set titlestring=\\afoo\\abar\\a
+echo &titlestring
+set titlestring=\\ foo\\ bar\\  " comment
+echo &titlestring
+set titlestring=\\ foo\\ bar\\ 
+echo &titlestring
+set titlestring=\\|foo\\|bar\\| " comment
+echo &titlestring
+set titlestring=\\|foo\\|bar\\|
+echo &titlestring
+set titlestring=\\"foo\\"bar\\" " comment
+echo &titlestring
+set titlestring=\\"foo\\"bar\\"
+echo &titlestring
+
+echo "-- 3 --"
+set titlestring=\\\afoo\\\abar\\\a " comment
+echo &titlestring
+set titlestring=\\\afoo\\\abar\\\a
+echo &titlestring
+set titlestring=\\\ foo\\\ bar\\\  " comment
+echo &titlestring
+set titlestring=\\\ foo\\\ bar\\\ 
+echo &titlestring
+set titlestring=\\\|foo\\\|bar\\\| " comment
+echo &titlestring
+set titlestring=\\\|foo\\\|bar\\\|
+echo &titlestring
+set titlestring=\\\"foo\\\"bar\\\" " comment
+echo &titlestring
+set titlestring=\\\"foo\\\"bar\\\"
+echo &titlestring
+
+echo "-- 4 --"
+set titlestring=\\\\afoo\\\\abar\\\\a " comment
+echo &titlestring
+set titlestring=\\\\afoo\\\\abar\\\\a
+echo &titlestring
+set titlestring=\\\\ foo\\\\ bar\\\\  " comment
+echo &titlestring
+set titlestring=\\\\ foo\\\\ bar\\\\ 
+echo &titlestring
+set titlestring=\\\\|foo\\\\|bar\\\\| " comment
+echo &titlestring
+set titlestring=\\\\|foo\\\\|bar\\\\|
+echo &titlestring
+set titlestring=\\\\"foo\\\\"bar\\\\" " comment
+echo &titlestring
+set titlestring=foo\\\\"\\\\"bar\\\\"
+echo &titlestring
+
diff --git a/runtime/syntax/vim.vim b/runtime/syntax/vim.vim
index 2a833e4d8d..228e741df5 100644
--- a/runtime/syntax/vim.vim
+++ b/runtime/syntax/vim.vim
@@ -2,7 +2,7 @@
 " Language:	   Vim script
 " Maintainer:	   Hirohito Higashi <h.east.727 ATMARK gmail.com>
 "	   Doug Kearns <dougkearns@gmail.com>
-" Last Change:	   2025 Mar 29
+" Last Change:	   2025 Apr 03
 " Former Maintainer: Charles E. Campbell
 
 " DO NOT CHANGE DIRECTLY.
@@ -823,12 +823,31 @@ syn match	vimCmplxRepeat	'@[0-9a-z".=@:]\ze\($\|[^a-zA-Z]\>\)'
 
 " Set command and associated set-options (vimOptions) with comment {{{2
 syn match	vimSet		"\<\%(setl\%[ocal]\|setg\%[lobal]\|se\%[t]\)\>" skipwhite nextgroup=vimSetBang,vimSetArgs
-syn region	vimSetArgs	contained	start="\S" skip=+\\|\|\n\s*\\\|\n\s*["#]\\ + matchgroup=vimCmdSep end="|" end="$" matchgroup=vimNotation end="<[cC][rR]>" keepend contains=@vimComment,@vimContinue,vimErrSetting,vimOption,vimSetAll,vimSetTermcap
-syn region	vimSetEqual	contained	matchgroup=vimOper start="[=:]\|[-+^]=" skip=+\\|\|\\\s\|\n\s*\\\|\n\s*["#]\\ \|^\s*\\\|^\s*["#]\\ + matchgroup=vimCmdSep end="|" end="\ze\s" end="$" contains=@vimContinue,vimCtrlChar,vimEnvvar,vimNotation,vimSetSep
+syn region	vimSetComment	contained	start=+"+ skip=+\n\s*\%(\\\||"\\ \)+ end="$" contains=@vimCommentGroup,vimCommentString extend
+syn match	vimSetCmdSep	contained	"|" skipwhite nextgroup=@vimCmdList,vimSubst1,vimFunc
+syn match	vimSetEscape	contained	"\\\%(\\[|"]\|.\)"
+syn match	vimSetBarEscape	contained	"\\|"
+syn match	vimSetQuoteEscape	contained	+\\"+
+syn region	vimSetArgs	contained
+      \ start="\S"
+      \ skip=+\n\s*\%(\\\|["#]\\ \)\|^\s*"\\ +
+      \ end=+\ze\\\@1<![|"]+
+      "\ assume this isn't an escaped char with backslash on the previous line
+      \ end=+^\s*\\\ze[|"]+
+      \ end="\ze\s#"
+      \ end="$"
+      \ nextgroup=vimSetCmdSep,vimSetComment,vim9Comment
+      \ contains=@vimContinue,vimErrSetting,vimOption,vimSetAll,vimSetTermcap
+      \ keepend
+syn region	vimSetEqual	contained
+      \ matchgroup=vimOper
+      \ start="[=:]\|[-+^]="
+      \ skip=+\\\s\|^\s*\%(\\\|["#]\\ \)+
+      \ end="\ze\s"
+      \ contains=@vimContinue,vimCtrlChar,vimEnvvar,vimNotation,vimSetSep,vimSetEscape,vimSetBarEscape,vimSetQuoteEscape
 syn match	vimSetBang	contained	"\a\@1<=!" skipwhite nextgroup=vimSetAll,vimSetTermcap
 syn keyword	vimSetAll	contained	all nextgroup=vimSetMod
 syn keyword	vimSetTermcap	contained	termcap
-syn region	vimSetString	contained	start=+="+hs=s+1	skip=+\\\\\|\\"+  end=+"+	contains=vimCtrlChar
 syn match	vimSetSep	contained	"[,:]"
 syn match	vimSetMod	contained	"\a\@1<=\%(&vim\=\|[!&?<]\)"
 
@@ -1682,9 +1701,9 @@ if !exists("skip_vim_syntax_inits")
  hi def link vimSet	vimCommand
  hi def link vimSetAll	vimOption
  hi def link vimSetBang	vimBang
+ hi def link vimSetComment	vimComment
  hi def link vimSetMod	vimOption
  hi def link vimSetSep	vimSep
- hi def link vimSetString	vimString
  hi def link vimSetTermcap	vimOption
  hi def link vimShebang	PreProc
  hi def link vimSleep	vimCommand