Origin:
https://sourceforge.net/p/mcj/tickets/184/
https://sourceforge.net/p/mcj/fig2dev/ci/ff9aba206a30288f456dfc91584a52ba9927b438/

--- a/fig2dev/read.c
+++ b/fig2dev/read.c
@@ -1058,6 +1058,14 @@
 							line_no);
 					return -1;
 				}
+				if (l->type == T_ARC_BOX && l->radius == 0) {
+					put_msg("A %s, but zero corner radius "
+							"at line %d - convert "
+							"to a rectangle.",
+							obj_name[l->type - 2],
+							line_no);
+					l->type = T_BOX;
+				}
 			}
 
 		} else { /* T_BOX || T_POLYGON */
--- a/fig2dev/tests/read.at
+++ b/fig2dev/tests/read.at
@@ -123,6 +123,17 @@
 ])
 AT_CLEANUP
 
+AT_SETUP([convert an arc-box with zero radius to a box])
+AT_KEYWORDS(read.c arc-box)
+AT_CHECK([fig2dev -L pict2e <<EOF
+FIG_FILE_TOP
+2 4 1 1 0 0 50 -1 -1 4.0 0 0 0 0 0 5
+	0 0 300 0 300 300 0 300 0 0
+EOF
+],0,ignore,[A rectangle with rounded corners, but zero corner radius at line 11 - convert to a rectangle.
+])
+AT_CLEANUP
+
 AT_SETUP([fail on a malformed arc-box])
 AT_KEYWORDS(read.c malformed arc-box)
 AT_CHECK([fig2dev -L pict2e <<EOF