c9bbfcb's commit message floated a follow-up — "lib/log can revert
format→fmt now that the silent crash is impossible." That note was
wrong. #19's rule is decl-site and body-blind by design (single
rule, no non-local reasoning), so any `fn x(fmt: str)` under
`use fmt;` is refused regardless of whether the body calls fmt.X.
Rename infeasible.
Rewrite the header bullet to drop the wishlist sentence and state
the constraint directly: ww's `.` overload for both module-access
and field-access makes `use fmt; fn x(fmt: T)` structurally
ambiguous, and #19 refuses it at decl. The `format` parameter name
stays.
Comment-only; no test surface.
Hojun-Cho
1bf53c2184