feat(highlight)!: error on invalid names and allow '.' and '@'

Previously if a highlight group with a name outside the regexp
[a-zA-Z0-9_] was defined, Nvim would emit an "invalid character"
warning message. This was annoying for Lua scripts, as it was very hard
to debug what line of code was triggering this message since it didn't
produce a stack trace.

This has now been promoted to an error with the code E5248.

Additionally the ASCII character period ('.') and at-sign ('@') have
been added to the allowed list of characters of a highlight group name
to support the application of defining hierarchical highlight groups,
e.g. 'TS.keyword'.

Co-authored-by: Christian Clason <christian.clason@uni-due.de>

32 files changed, 80 insertions, 78 deletions

diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 231220c319..67cd21e172 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -1021,6 +1021,8 @@ EXTERN char e_resulting_text_too_long[] INIT(= N_("E1240: Resulting text too lon
 
 EXTERN char e_line_number_out_of_range[] INIT(= N_("E1247: Line number out of range"));
 
+EXTERN char e_highlight_group_name_invalid_char[] INIT(= N_("E5248: Invalid character in group name"));
+
 EXTERN char e_highlight_group_name_too_long[] INIT(= N_("E1249: Highlight group name too long"));
 
 EXTERN char e_undobang_cannot_redo_or_move_branch[]
diff --git a/src/nvim/highlight_group.c b/src/nvim/highlight_group.c
index 04aecc6c3a..ab241516e4 100644
--- a/src/nvim/highlight_group.c
+++ b/src/nvim/highlight_group.c
@@ -1750,11 +1750,11 @@ static int syn_add_group(const char *name, size_t len)
     if (!vim_isprintc(c)) {
       emsg(_("E669: Unprintable character in group name"));
       return 0;
-    } else if (!ASCII_ISALNUM(c) && c != '_') {
-      // This is an error, but since there previously was no check only give a warning.
+    } else if (!ASCII_ISALNUM(c) && c != '_' && c != '.' && c != '@') {
+      // '.' and '@' are allowed characters for use with treesitter capture names.
       msg_source(HL_ATTR(HLF_W));
-      msg(_("W18: Invalid character in group name"));
-      break;
+      emsg(_(e_highlight_group_name_invalid_char));
+      return 0;
     }
   }
 
diff --git a/src/nvim/po/af.po b/src/nvim/po/af.po
index 82345f8a46..d64789660e 100644
--- a/src/nvim/po/af.po
+++ b/src/nvim/po/af.po
@@ -5320,8 +5320,8 @@ msgstr "E424: Te veel verskillende uitlig-eienskappe in gebruik"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Onvertoonbare karakter in groepnaam"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ongeldige karakter groepnaam"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ongeldige karakter groepnaam"
 
 #~ msgid "E849: Too many highlight and syntax groups"
 #~ msgstr ""
diff --git a/src/nvim/po/ca.po b/src/nvim/po/ca.po
index 6c4d6ddd22..5869e6567c 100644
--- a/src/nvim/po/ca.po
+++ b/src/nvim/po/ca.po
@@ -5983,9 +5983,9 @@ msgstr "E424: Hi ha massa atributs de ressalt diferents en �s"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Car�cter no imprimible en el nom del grup"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Hi ha un car�cter no v�lid en el nom del grup"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Hi ha un car�cter no v�lid en el nom del grup"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/cs.cp1250.po b/src/nvim/po/cs.cp1250.po
index 859039eb87..bce5c0fa76 100644
--- a/src/nvim/po/cs.cp1250.po
+++ b/src/nvim/po/cs.cp1250.po
@@ -6072,10 +6072,10 @@ msgstr ""
 msgid "E669: Unprintable character in group name"
 msgstr ""
 
-#: ../syntax.c:7434
+#: ../highlight_group.c:1756
 #, fuzzy
-msgid "W18: Invalid character in group name"
-msgstr "E182: Chybn� jm�no p��kazu"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Chybn� jm�no p��kazu"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/cs.po b/src/nvim/po/cs.po
index 4d9ad58836..f4eab3f0d4 100644
--- a/src/nvim/po/cs.po
+++ b/src/nvim/po/cs.po
@@ -6072,10 +6072,10 @@ msgstr ""
 msgid "E669: Unprintable character in group name"
 msgstr ""
 
-#: ../syntax.c:7434
+#: ../highlight_group.c:1756
 #, fuzzy
-msgid "W18: Invalid character in group name"
-msgstr "E182: Chybn� jm�no p��kazu"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Chybn� jm�no p��kazu"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/da.po b/src/nvim/po/da.po
index dfcc052288..1c3284f867 100644
--- a/src/nvim/po/da.po
+++ b/src/nvim/po/da.po
@@ -5599,8 +5599,8 @@ msgstr "E424: For mange forskellige fremhævningsattributter i brug"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Tegn som ikke kan udskrives i gruppenavn"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ugyldige tegn i gruppenavn"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ugyldige tegn i gruppenavn"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: For mange fremhævnings- og syntaksgrupper"
diff --git a/src/nvim/po/de.po b/src/nvim/po/de.po
index 2dde77e9f7..ce3fd77ede 100644
--- a/src/nvim/po/de.po
+++ b/src/nvim/po/de.po
@@ -5408,8 +5408,8 @@ msgid "E669: Unprintable character in group name"
 msgstr "E669: Nicht druckbare Zeichen im Namen der Gruppe"
 
 #: ../syntax.c:7304
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ung�ltiges Zeichen im Namen der Gruppe"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ung�ltiges Zeichen im Namen der Gruppe"
 
 #: ../syntax.c:7318
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/en_GB.po b/src/nvim/po/en_GB.po
index 66cdba6f92..81ee9ed6a0 100644
--- a/src/nvim/po/en_GB.po
+++ b/src/nvim/po/en_GB.po
@@ -5730,8 +5730,8 @@ msgstr ""
 msgid "E669: Unprintable character in group name"
 msgstr ""
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
 msgstr ""
 
 #: ../syntax.c:7448
diff --git a/src/nvim/po/eo.po b/src/nvim/po/eo.po
index 1c503d0a84..263fb61b18 100644
--- a/src/nvim/po/eo.po
+++ b/src/nvim/po/eo.po
@@ -5378,8 +5378,8 @@ msgstr "E424: Tro da malsamaj atributoj de emfazo uzataj"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Nepresebla signo en nomo de grupo"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Nevalida signo en nomo de grupo"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Nevalida signo en nomo de grupo"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: Tro da emfazaj kaj sintaksaj grupoj"
diff --git a/src/nvim/po/es.po b/src/nvim/po/es.po
index adea651b7c..8a44f6a534 100644
--- a/src/nvim/po/es.po
+++ b/src/nvim/po/es.po
@@ -6053,9 +6053,9 @@ msgstr "E669: Carácter no imprimible en el nombre del grupo"
 
 # This is an error, but since there previously was no check only
 # * give a warning.
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Hay un carácter no válido en el nombre del grupo"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Hay un carácter no válido en el nombre del grupo"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/fi.po b/src/nvim/po/fi.po
index f10d4ce977..1c0da244ba 100644
--- a/src/nvim/po/fi.po
+++ b/src/nvim/po/fi.po
@@ -5369,8 +5369,8 @@ msgstr "E424: Liikaa eri korostusattribuutteja"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Tulostuskelvoton merkki ryhmän nimessä"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Virheellinen merkki ryhmän nimessä"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Virheellinen merkki ryhmän nimessä"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: Liikaa korostuksia ja syntaksiryhmiä"
diff --git a/src/nvim/po/fr.po b/src/nvim/po/fr.po
index 614ba013e6..be2141cd6d 100644
--- a/src/nvim/po/fr.po
+++ b/src/nvim/po/fr.po
@@ -2040,8 +2040,8 @@ msgstr ""
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Caract�re non imprimable dans un nom de groupe"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Caract�re invalide dans un nom de groupe"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Caract�re invalide dans un nom de groupe"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: Trop de groupes de surbrillance et de syntaxe"
diff --git a/src/nvim/po/ga.po b/src/nvim/po/ga.po
index 1c25ee481c..346f0faa84 100644
--- a/src/nvim/po/ga.po
+++ b/src/nvim/po/ga.po
@@ -5668,8 +5668,8 @@ msgstr "E424: An iomarca tr�ithe aibhsithe in �s�id"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Carachtar neamhghrafach in ainm gr�pa"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Carachtar neamhbhail� in ainm gr�pa"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Carachtar neamhbhail� in ainm gr�pa"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: An iomarca gr�pa� aibhsithe agus comhr�ire"
diff --git a/src/nvim/po/it.po b/src/nvim/po/it.po
index 313280c807..152ed2cbe3 100644
--- a/src/nvim/po/it.po
+++ b/src/nvim/po/it.po
@@ -6046,9 +6046,9 @@ msgstr "E424: Troppi gruppi evidenziazione differenti in uso"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Carattere non stampabile in un nome di gruppo"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Carattere non ammesso in un nome di gruppo"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Carattere non ammesso in un nome di gruppo"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/ko.UTF-8.po b/src/nvim/po/ko.UTF-8.po
index b99c22caeb..09be710374 100644
--- a/src/nvim/po/ko.UTF-8.po
+++ b/src/nvim/po/ko.UTF-8.po
@@ -5913,9 +5913,9 @@ msgstr "E424: 너무 많은 다른 하이라이트 속성이 사용되고 있습
 msgid "E669: Unprintable character in group name"
 msgstr "E669: 그룹 이름에 출력할 수 없는 문자가 있습니다"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: 그룹 이름에 이상한 문자"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: 그룹 이름에 이상한 문자"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/nb.po b/src/nvim/po/nb.po
index 2285d755cf..9bc730ae71 100644
--- a/src/nvim/po/nb.po
+++ b/src/nvim/po/nb.po
@@ -5930,9 +5930,9 @@ msgstr "E424: For mange forskjellige uthevingsattributter i bruk"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Ikke-skrivbart tegn i gruppenavn"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ugyldig tegn i gruppenavn"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ugyldig tegn i gruppenavn"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/nl.po b/src/nvim/po/nl.po
index 00d113c83c..4d2e55adc6 100644
--- a/src/nvim/po/nl.po
+++ b/src/nvim/po/nl.po
@@ -5913,8 +5913,8 @@ msgstr ""
 msgid "E669: Unprintable character in group name"
 msgstr ""
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
 msgstr ""
 
 #: ../syntax.c:7448
diff --git a/src/nvim/po/no.po b/src/nvim/po/no.po
index 2285d755cf..9bc730ae71 100644
--- a/src/nvim/po/no.po
+++ b/src/nvim/po/no.po
@@ -5930,9 +5930,9 @@ msgstr "E424: For mange forskjellige uthevingsattributter i bruk"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Ikke-skrivbart tegn i gruppenavn"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ugyldig tegn i gruppenavn"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ugyldig tegn i gruppenavn"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/pl.UTF-8.po b/src/nvim/po/pl.UTF-8.po
index 5f1779d1bd..7e978113f6 100644
--- a/src/nvim/po/pl.UTF-8.po
+++ b/src/nvim/po/pl.UTF-8.po
@@ -5908,9 +5908,9 @@ msgstr "E424: Zbyt wiele różnych atrybutów podkreślania w użyciu"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Niedrukowalny znak w nazwie grupy"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: nieprawidłowy znak w nazwie grupy"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: nieprawidłowy znak w nazwie grupy"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/pt_BR.po b/src/nvim/po/pt_BR.po
index 533d916de1..bfd64b4d28 100644
--- a/src/nvim/po/pt_BR.po
+++ b/src/nvim/po/pt_BR.po
@@ -6070,8 +6070,8 @@ msgid "E669: Unprintable character in group name"
 msgstr "E669: Caractere n�o-imprim�vel no nome do grupo"
 
 #: ../syntax.c:7320
-msgid "W18: Invalid character in group name"
-msgstr "W18: Caractere inv�lido no nome do grupo"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Caractere inv�lido no nome do grupo"
 
 #: ../syntax.c:7334
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/ru.po b/src/nvim/po/ru.po
index 7566036d3e..da356770d7 100644
--- a/src/nvim/po/ru.po
+++ b/src/nvim/po/ru.po
@@ -5977,9 +5977,9 @@ msgstr "E424: Используется слишком много разных а
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Непечатный символ в имени группы"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Недопустимый символ в имени группы"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Недопустимый символ в имени группы"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/sk.cp1250.po b/src/nvim/po/sk.cp1250.po
index ff95c68a12..cb8b8c6abb 100644
--- a/src/nvim/po/sk.cp1250.po
+++ b/src/nvim/po/sk.cp1250.po
@@ -5940,9 +5940,9 @@ msgstr "E424: Pou��van�ch pr�li� ve�a odli�n�ch zv�raz�ovac�ch vlastnost�"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Netla�iteln� znak v mene skupiny"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Chybn� znak v mene skupiny"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Chybn� znak v mene skupiny"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/sk.po b/src/nvim/po/sk.po
index d35622726f..4f9e1fe185 100644
--- a/src/nvim/po/sk.po
+++ b/src/nvim/po/sk.po
@@ -5940,9 +5940,9 @@ msgstr "E424: Pou��van�ch pr�li� ve�a odli�n�ch zv�raz�ovac�ch vlastnost�"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Netla�iteln� znak v mene skupiny"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Chybn� znak v mene skupiny"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Chybn� znak v mene skupiny"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/sr.po b/src/nvim/po/sr.po
index 3c45e1bf80..cbdf736d0f 100644
--- a/src/nvim/po/sr.po
+++ b/src/nvim/po/sr.po
@@ -6050,8 +6050,8 @@ msgstr "E424: У употреби је превише различитих ат�
 msgid "E669: Unprintable character in group name"
 msgstr "E669: У имену групе је карактер који не може да се штампа"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Неважећи карактер у имену групе"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Неважећи карактер у имену групе"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: Превише синтаксних и група истицања"
diff --git a/src/nvim/po/sv.po b/src/nvim/po/sv.po
index d50c9d695d..406900f7b2 100644
--- a/src/nvim/po/sv.po
+++ b/src/nvim/po/sv.po
@@ -2056,8 +2056,8 @@ msgid "E669: Unprintable character in group name"
 msgstr "E669: Outskrivbart tecken i gruppnamn"
 
 #: ../syntax.c:7292
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ogiltigt tecken i gruppnamn"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ogiltigt tecken i gruppnamn"
 
 #: ../syntax.c:7306
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/tr.po b/src/nvim/po/tr.po
index fae2fd4967..20b667d198 100644
--- a/src/nvim/po/tr.po
+++ b/src/nvim/po/tr.po
@@ -3054,8 +3054,8 @@ msgstr "E423: İzin verilmeyen argüman: %s"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Grup adında yazdırılamayan karakter"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Grup adında geçersiz karakter"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Grup adında geçersiz karakter"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: Çok fazla vurgulama ve sözdizim grupları"
diff --git a/src/nvim/po/uk.po b/src/nvim/po/uk.po
index da87d50683..427abd9b77 100644
--- a/src/nvim/po/uk.po
+++ b/src/nvim/po/uk.po
@@ -3058,8 +3058,8 @@ msgstr "E423: Неправильний аргумент: %s"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Недруковний символ у назві групи"
 
-msgid "W18: Invalid character in group name"
-msgstr "W18: Некоректний символ у назві групи"
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Некоректний символ у назві групи"
 
 msgid "E849: Too many highlight and syntax groups"
 msgstr "E849: Забагато груп підсвічування і синтаксису"
diff --git a/src/nvim/po/vi.po b/src/nvim/po/vi.po
index c693f910d8..ad59718a30 100644
--- a/src/nvim/po/vi.po
+++ b/src/nvim/po/vi.po
@@ -5975,9 +5975,9 @@ msgstr "E424: Sử dụng quá nhiều thuộc tính chiếu sáng cú pháp"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: Ký tự không thể tin ra trong tên nhóm"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: Ký tự không cho phép trong tên nhóm"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: Ký tự không cho phép trong tên nhóm"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/zh_CN.UTF-8.po b/src/nvim/po/zh_CN.UTF-8.po
index 70c1389d7f..373833fa80 100644
--- a/src/nvim/po/zh_CN.UTF-8.po
+++ b/src/nvim/po/zh_CN.UTF-8.po
@@ -5942,9 +5942,9 @@ msgstr "E424: 使用了太多不同的高亮度属性"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: 组名中存在不可显示字符"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: 组名中含有无效字符"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: 组名中含有无效字符"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/po/zh_TW.UTF-8.po b/src/nvim/po/zh_TW.UTF-8.po
index e2fb2d39d4..5da69dfe69 100644
--- a/src/nvim/po/zh_TW.UTF-8.po
+++ b/src/nvim/po/zh_TW.UTF-8.po
@@ -5969,9 +5969,9 @@ msgstr "E424: 使用了過多相異的高亮度屬性"
 msgid "E669: Unprintable character in group name"
 msgstr "E669: 群組名稱中有無法列印的字元"
 
-#: ../syntax.c:7434
-msgid "W18: Invalid character in group name"
-msgstr "W18: 群組名稱中有不正確的字元"
+#: ../highlight_group.c:1756
+msgid "E5248: Invalid character in group name"
+msgstr "E5248: 群組名稱中有不正確的字元"
 
 #: ../syntax.c:7448
 msgid "E849: Too many highlight and syntax groups"
diff --git a/src/nvim/testdir/test_syntax.vim b/src/nvim/testdir/test_syntax.vim
index 7ba0149971..af93a37739 100644
--- a/src/nvim/testdir/test_syntax.vim
+++ b/src/nvim/testdir/test_syntax.vim
@@ -389,7 +389,7 @@ func Test_invalid_name()
   syn keyword Nop yes
   call assert_fails("syntax keyword Wr\x17ong bar", 'E669:')
   syntax keyword @Wrong bar
-  call assert_match('W18:', execute('1messages'))
+  call assert_fails("syntax keyword @#Wrong bar", 'E5248:')
   syn clear
   hi clear Nop
   hi clear @Wrong