4 files changed, 13 insertions, 0 deletions
diff --git a/mandoc.1 b/mandoc.1
index 9069e608..58c0812b 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -763,6 +763,11 @@ macro that could be represented using
 .Ic \&Fx ,
 or
 .Ic \&Dx .
+.It Sy "description line ends with a full stop"
+.Pq mdoc
+Do not use punctuation at the end of an
+.Ic \&Nd
+block.
 .El
 .Ss Warnings related to the document prologue
 .Bl -ohang
diff --git a/mandoc.h b/mandoc.h
index 37859b91..37baee40 100644
--- a/mandoc.h
+++ b/mandoc.h
@@ -48,6 +48,7 @@ enum	mandocerr {
 
 	MANDOCERR_MACRO_USELESS, /* useless macro: macro */
 	MANDOCERR_BX, /* consider using OS macro: macro */
+	MANDOCERR_ND_DOT, /* description line ends with a full stop */
 
 	MANDOCERR_WARNING, /* ===== start of warnings ===== */
 
diff --git a/mdoc_validate.c b/mdoc_validate.c
index 1a9dce2b..98e6a77d 100644
--- a/mdoc_validate.c
+++ b/mdoc_validate.c
@@ -1076,6 +1076,7 @@ static void
 post_nd(POST_ARGS)
 {
 	struct roff_node	*n;
+	size_t			 sz;
 
 	n = mdoc->last;
 
@@ -1089,6 +1090,11 @@ post_nd(POST_ARGS)
 	if (n->child == NULL)
 		mandoc_msg(MANDOCERR_ND_EMPTY, mdoc->parse,
 		    n->line, n->pos, "Nd");
+	else if (n->last->type == ROFFT_TEXT &&
+	    (sz = strlen(n->last->string)) != 0 &&
+	    n->last->string[sz - 1] == '.')
+		mandoc_msg(MANDOCERR_ND_DOT, mdoc->parse,
+		    n->last->line, n->last->pos + sz - 1, NULL);
 
 	post_hyph(mdoc);
 }
diff --git a/read.c b/read.c
index bd04a09c..e6d24444 100644
--- a/read.c
+++ b/read.c
@@ -90,6 +90,7 @@ static	const char * const	mandocerrs[MANDOCERR_MAX] = {
 
 	"useless macro",
 	"consider using OS macro",
+	"description line ends with a full stop",
 
 	"generic warning",