10 REM A GEN with no EMIT at all runs its FOR EACH/DO EACH body zero times.
20 GEN NOTHING(N#)
30 END GEN
40 FOR EACH X# IN NOTHING(0)
50     PRINT "NEVER FOR"
60 NEXT X#
70 PRINT "AFTER FOR"
80 DO EACH Y# IN NOTHING(0)
90     PRINT "NEVER DO"
100 LOOP
110 PRINT "AFTER DO"