Whether a dependency's names reach the modules that depend on this one

Decided

D-0058, settled by the language’s author: part of spec §18. Older text cites it as 18.58.

Private by default; pub = true re-exports it, nested under the exporting module (rl::shapes::Rectangle), and a dependent may name it itself with via = "rl::shapes". A private dependency’s type in a pub signature is an error (DZ0311). Nested rather than merged into the exporter’s names, because a wrapper usually reuses the names of what it wraps. Follows Java’s requires / requires transitive and Swift 6’s internal import / public import, which also rejects a public API naming an internally-imported type; Rust merely warns, and leaves users holding values whose type they cannot write (§3.2)