Block-scoped variables (those defined in block expressions for .map, .each, .filter) cause lint warnings when subscripted.
Given this class file:
The file validates just fine:
However, lint gives warnings about the subscripted block-scoped variable:
This can be worked around by putting the block-scoped variable in parentheses before the subscript:
The style guide gives no indication that parentheses are required in this usage, and the file validates (and functions) just fine, so this makes me think this is a bug in the linter.