If a node is tagged explicitly, skip implicit tagging for that node.

Apart from making sense in the first place, this fixes an assertion
failure that happened when the calculated implicit tag did not match
the string value of the first child of the node,

Bug found by tb@ using afl(1).

6 files changed, 51 insertions, 4 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Tg/Makefile b/regress/usr.bin/mandoc/mdoc/Tg/Makefile
index d67ec5affa8..83ae4160f6c 100644
--- a/regress/usr.bin/mandoc/mdoc/Tg/Makefile
+++ b/regress/usr.bin/mandoc/mdoc/Tg/Makefile
@@ -1,9 +1,9 @@
-# $OpenBSD: Makefile,v 1.2 2020/04/06 09:55:50 schwarze Exp $
+# $OpenBSD: Makefile,v 1.3 2022/04/26 11:28:35 schwarze Exp $
 
-REGRESS_TARGETS = column list warn
-TAG_TARGETS	= column list warn
+REGRESS_TARGETS = column implicit list warn
+TAG_TARGETS	= column implicit list warn
 LINT_TARGETS	= warn
-HTML_TARGETS	= column list warn
+HTML_TARGETS	= column implicit list warn
 
 SKIP_TMAN	= column
 
diff --git a/regress/usr.bin/mandoc/mdoc/Tg/implicit.in b/regress/usr.bin/mandoc/mdoc/Tg/implicit.in
new file mode 100644
index 00000000000..9abd23c9231
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Tg/implicit.in
@@ -0,0 +1,14 @@
+.\" $OpenBSD: implicit.in,v 1.1 2022/04/26 11:28:35 schwarze Exp $
+.Dd $Mdocdate: April 26 2022 $
+.Dt TG-IMPLICIT 1
+.Os
+.Sh NAME
+.Nm Tg-implicit
+.Nd overriding implicit tagging
+.Sh DESCRIPTION
+BEGINTEST
+.Pp
+.Tg explicit
+.Sy implicit is unsused
+.Pp
+ENDTEST
diff --git a/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_ascii b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_ascii
new file mode 100644
index 00000000000..e3618686b86
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_ascii
@@ -0,0 +1,13 @@
+TG-IMPLICIT(1)              General Commands Manual             TG-IMPLICIT(1)
+
+NNAAMMEE
+     TTgg--iimmpplliicciitt - overriding implicit tagging
+
+DDEESSCCRRIIPPTTIIOONN
+     BEGINTEST
+
+     iimmpplliicciitt iiss uunnssuusseedd
+
+     ENDTEST
+
+OpenBSD                         April 26, 2022                         OpenBSD
diff --git a/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_html b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_html
new file mode 100644
index 00000000000..93df918de1b
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_html
@@ -0,0 +1,2 @@
+<p class="Pp" id="explicit"><a class="permalink" href="#explicit"><b class="Sy">implicit
+    is unsused</b></a></p>
diff --git a/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_markdown b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_markdown
new file mode 100644
index 00000000000..6511e44173e
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_markdown
@@ -0,0 +1,15 @@
+TG-IMPLICIT(1) - General Commands Manual
+
+# NAME
+
+**Tg-implicit** - overriding implicit tagging
+
+# DESCRIPTION
+
+BEGINTEST
+
+**implicit is unsused**
+
+ENDTEST
+
+OpenBSD - April 26, 2022
diff --git a/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_tag b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_tag
new file mode 100644
index 00000000000..b7b9a92768e
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Tg/implicit.out_tag
@@ -0,0 +1,3 @@
+NAME implicit.mandoc_ascii 3
+DESCRIPTION implicit.mandoc_ascii 6
+explicit implicit.mandoc_ascii 9