Flattens nested dot object access into one canonical dot form.

The trailing forms are retained as method arguments, so (. (. a ["name"]) ["hello"] (run 1 2 3)) becomes (. a ["name"] ["hello"] (run 1 2 3)).

Returns true when a destructuring var source can be safely read directly.

Direct destructuring repeats the source once per bound field, so the source must be a symbol or a one-level dot access on a symbol.

Suggests merging adjacent same-object dot bindings into one destructuring var.