diff --git a/src/cmd/ksh93/tests/io.sh b/src/cmd/ksh93/tests/io.sh
index c5ce484c4..560e10e06 100755
--- a/src/cmd/ksh93/tests/io.sh
+++ b/src/cmd/ksh93/tests/io.sh
@@ -618,5 +618,19 @@ fi
 (exec 7>bad.txt; "$SHELL" -c 'print bad >&7' 2>/dev/null)
 [[ $(<bad.txt) == '' ]] || err_exit 'File descriptors > 2 inherited without POSIX mode' "(got $actual)"
 
+# ======
+# File descriptor leak with process substitution
+err=$(
+	ulimit -n 15 || exit 0
+	fdUser() {
+		:
+	}
+	set +x
+	for ((i=1; i<10; i++))
+	do	fdUser <(:) >(:) || exit
+	done 2>&1
+) || err_exit 'Process substitution leaks file descriptors when used as argument to function' \
+	"(got $(printf %q "$err"))"
+
 # ======
 exit $((Errors<125?Errors:125))