The .AT, .DT, and .UC macros are allowed inside next-line scope

and never produce output at the place of their invocation.

Minibugs found while investigating unrelated afl(1) reports from tb@.

12 files changed, 106 insertions, 10 deletions

diff --git a/regress/usr.bin/mandoc/man/AT/Makefile b/regress/usr.bin/mandoc/man/AT/Makefile
new file mode 100644
index 00000000000..44cf05195ce
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/AT/Makefile
@@ -0,0 +1,5 @@
+# $OpenBSD: Makefile,v 1.1 2022/04/27 17:04:15 schwarze Exp $
+
+REGRESS_TARGETS	 = basic
+
+.include <bsd.regress.mk>
diff --git a/regress/usr.bin/mandoc/man/AT/basic.in b/regress/usr.bin/mandoc/man/AT/basic.in
new file mode 100644
index 00000000000..35eb2375a17
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/AT/basic.in
@@ -0,0 +1,10 @@
+.\" $OpenBSD: basic.in,v 1.1 2022/04/27 17:04:15 schwarze Exp $
+.TH AT-BASIC 1 "April 27, 2022"
+.SH NAME
+AT-basic \- the AT&T footer macro
+.SH DESCRIPTION
+initial text
+.B
+.AT
+bold text
+final text
diff --git a/regress/usr.bin/mandoc/man/AT/basic.out_ascii b/regress/usr.bin/mandoc/man/AT/basic.out_ascii
new file mode 100644
index 00000000000..962c9f8852c
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/AT/basic.out_ascii
@@ -0,0 +1,9 @@
+AT-BASIC(1)                 General Commands Manual                AT-BASIC(1)
+
+NNAAMMEE
+       AT-basic - the AT&T footer macro
+
+DDEESSCCRRIIPPTTIIOONN
+       initial text bboolldd tteexxtt final text
+
+7th Edition                     April 27, 2022                     AT-BASIC(1)
diff --git a/regress/usr.bin/mandoc/man/DT/Makefile b/regress/usr.bin/mandoc/man/DT/Makefile
new file mode 100644
index 00000000000..44cf05195ce
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/DT/Makefile
@@ -0,0 +1,5 @@
+# $OpenBSD: Makefile,v 1.1 2022/04/27 17:04:15 schwarze Exp $
+
+REGRESS_TARGETS	 = basic
+
+.include <bsd.regress.mk>
diff --git a/regress/usr.bin/mandoc/man/DT/basic.in b/regress/usr.bin/mandoc/man/DT/basic.in
new file mode 100644
index 00000000000..8902e59453c
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/DT/basic.in
@@ -0,0 +1,22 @@
+.\" $OpenBSD: basic.in,v 1.1 2022/04/27 17:04:15 schwarze Exp $
+.TH DT-BASIC 1 "April 27, 2022"
+.SH NAME
+DT-basic \- restore the default tabulator positions
+.SH DESCRIPTION
+.nf
+Default tabs are every five columns:
+1234 1234 1234 1234 1234
+one	two	three	four
+.PP
+Custom tabs: column 6, then every 8 columns:
+12345 1234567 1234567 1234567
+.ta 6n T 8n
+one	two	three	four
+.PP
+.B
+.DT
+bold text
+.PP
+Back to the default:
+1234 1234 1234 1234 1234
+one	two	three	four
diff --git a/regress/usr.bin/mandoc/man/DT/basic.out_ascii b/regress/usr.bin/mandoc/man/DT/basic.out_ascii
new file mode 100644
index 00000000000..8ccbc685c20
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/DT/basic.out_ascii
@@ -0,0 +1,21 @@
+DT-BASIC(1)                 General Commands Manual                DT-BASIC(1)
+
+NNAAMMEE
+       DT-basic - restore the default tabulator positions
+
+DDEESSCCRRIIPPTTIIOONN
+       Default tabs are every five columns:
+       1234 1234 1234 1234 1234
+       one  two  three     four
+
+       Custom tabs: column 6, then every 8 columns:
+       12345 1234567 1234567 1234567
+       one   two     three   four
+
+       bboolldd tteexxtt
+
+       Back to the default:
+       1234 1234 1234 1234 1234
+       one  two  three     four
+
+OpenBSD                         April 27, 2022                     DT-BASIC(1)
diff --git a/regress/usr.bin/mandoc/man/Makefile b/regress/usr.bin/mandoc/man/Makefile
index 23d6e04b3f3..17a939b2243 100644
--- a/regress/usr.bin/mandoc/man/Makefile
+++ b/regress/usr.bin/mandoc/man/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.19 2019/01/05 21:13:55 schwarze Exp $
+# $OpenBSD: Makefile,v 1.20 2022/04/27 17:04:15 schwarze Exp $
 
-SUBDIR = B BI EX HP IP MT OP PD PP RS SH SS SY TH TP TS UR nf blank
+SUBDIR = AT B BI DT EX HP IP MT OP PD PP RS SH SS SY TH TP TS UC UR nf blank
 
 .include "../Makefile.sub"
 .include <bsd.subdir.mk>
diff --git a/regress/usr.bin/mandoc/man/UC/Makefile b/regress/usr.bin/mandoc/man/UC/Makefile
new file mode 100644
index 00000000000..44cf05195ce
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/UC/Makefile
@@ -0,0 +1,5 @@
+# $OpenBSD: Makefile,v 1.1 2022/04/27 17:04:15 schwarze Exp $
+
+REGRESS_TARGETS	 = basic
+
+.include <bsd.regress.mk>
diff --git a/regress/usr.bin/mandoc/man/UC/basic.in b/regress/usr.bin/mandoc/man/UC/basic.in
new file mode 100644
index 00000000000..f6f71be0521
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/UC/basic.in
@@ -0,0 +1,10 @@
+.\" $OpenBSD: basic.in,v 1.1 2022/04/27 17:04:15 schwarze Exp $
+.TH UC-BASIC 1 "April 27, 2022"
+.SH NAME
+UC-basic \- the University of California footer macro
+.SH DESCRIPTION
+initial text
+.B
+.UC
+bold text
+final text
diff --git a/regress/usr.bin/mandoc/man/UC/basic.out_ascii b/regress/usr.bin/mandoc/man/UC/basic.out_ascii
new file mode 100644
index 00000000000..fa29e19d396
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/UC/basic.out_ascii
@@ -0,0 +1,9 @@
+UC-BASIC(1)                 General Commands Manual                UC-BASIC(1)
+
+NNAAMMEE
+       UC-basic - the University of California footer macro
+
+DDEESSCCRRIIPPTTIIOONN
+       initial text bboolldd tteexxtt final text
+
+3rd Berkeley Distribution       April 27, 2022                     UC-BASIC(1)
diff --git a/usr.bin/mandoc/man_macro.c b/usr.bin/mandoc/man_macro.c
index 779b28278fe..10f07763f7f 100644
--- a/usr.bin/mandoc/man_macro.c
+++ b/usr.bin/mandoc/man_macro.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: man_macro.c,v 1.108 2022/04/13 14:37:34 schwarze Exp $ */
+/* $OpenBSD: man_macro.c,v 1.109 2022/04/27 17:04:15 schwarze Exp $ */
 /*
  * Copyright (c) 2012-2015,2017-2020,2022 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -63,10 +63,10 @@ static const struct man_macro man_macros[MAN_MAX - MAN_TH] = {
 	{ in_line_eoln, 0 }, /* RI */
 	{ blk_close, MAN_XSCOPE }, /* RE */
 	{ blk_exp, MAN_XSCOPE }, /* RS */
-	{ in_line_eoln, 0 }, /* DT */
-	{ in_line_eoln, 0 }, /* UC */
+	{ in_line_eoln, MAN_NSCOPED }, /* DT */
+	{ in_line_eoln, MAN_NSCOPED }, /* UC */
 	{ in_line_eoln, MAN_NSCOPED }, /* PD */
-	{ in_line_eoln, 0 }, /* AT */
+	{ in_line_eoln, MAN_NSCOPED }, /* AT */
 	{ in_line_eoln, MAN_NSCOPED }, /* in */
 	{ blk_imp, MAN_XSCOPE }, /* SY */
 	{ blk_close, MAN_XSCOPE }, /* YS */
diff --git a/usr.bin/mandoc/man_term.c b/usr.bin/mandoc/man_term.c
index 375555025e0..2152cdea691 100644
--- a/usr.bin/mandoc/man_term.c
+++ b/usr.bin/mandoc/man_term.c
@@ -1,6 +1,6 @@
-/* $OpenBSD: man_term.c,v 1.189 2021/06/28 19:49:57 schwarze Exp $ */
+/* $OpenBSD: man_term.c,v 1.190 2022/04/27 17:04:15 schwarze Exp $ */
 /*
- * Copyright (c) 2010-2015, 2017-2020 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2015,2017-2020,2022 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  *
  * Permission to use, copy, modify, and distribute this software for any
@@ -119,10 +119,10 @@ static const struct man_term_act man_term_acts[MAN_MAX - MAN_TH] = {
 	{ pre_alternate, NULL, 0 }, /* RI */
 	{ NULL, NULL, 0 }, /* RE */
 	{ pre_RS, post_RS, 0 }, /* RS */
-	{ pre_DT, NULL, 0 }, /* DT */
+	{ pre_DT, NULL, MAN_NOTEXT }, /* DT */
 	{ pre_ign, NULL, MAN_NOTEXT }, /* UC */
 	{ pre_PD, NULL, MAN_NOTEXT }, /* PD */
-	{ pre_ign, NULL, 0 }, /* AT */
+	{ pre_ign, NULL, MAN_NOTEXT }, /* AT */
 	{ pre_in, NULL, MAN_NOTEXT }, /* in */
 	{ pre_SY, post_SY, 0 }, /* SY */
 	{ NULL, NULL, 0 }, /* YS */