\unset ECHO
1|dotted numeric index selects array element|b
2|out-of-range index misses|
3|non-numeric index misses|
4|negative index misses|
5|trailing garbage after digits misses|
6|chained dotted index into a nested array|y
7|dotted index feeds section truthiness (truthy element)|yes
8|dotted index feeds section truthiness (falsey element)|