1define outer
 2  define inner
 3PASS
 4   endef
 5  define inner_fail
 6FAIL
 7    endef
 8endef
 9
10# Prefixed defines don't increase the nest level.
11define outer_override
12override define inner2
13export define inner3
14endef
15
16A := $(inner_fail)
17$(eval $(outer))
18
19foo:
20	echo $(A)
21	echo $(inner)