bug: fails to populate array within an array

[kamilkisiela]

The valBeforeLast is undefined for deeply nested paths.

See child-type-mismatch test. The paths are missing an property with an index number from the inner (second) array.

Got
  accounts.0.similarAccounts.similarAccounts.name
Expected
  accounts.0.similarAccounts.[0|1].similarAccounts.name

• [x] simplify the code
• [x] explain it
• [x] better function names