Pure refactor, semantics identical: the read_le_u64_into call (whose
chunks/zip iterators are opaque to the extraction) becomes an explicit
nested index loop, the same shape as the proven from_bytes_wide unpack.
With this the entire vartime_double_base::mul extraction closure is
self-contained: zero external axioms, zero sorries.
Adds a lints section to the top of lib.rs with the following:
#![warn(
clippy::unwrap_used,
missing_docs,
rust_2018_idioms,
unused_lifetimes,
unused_qualifications
)]
`warn` is used instead of `deny` to prevent the lints from firing during
local development, however we already configure `-D warnings` in CI so
if any lint fails on checked-in code, it will cause a CI failure.
This commit also fixes or explicitly allows any current violations of
these lints. The main ones were:
- `clippy::unwrap_used`: replaces usages of `unwrap` with `expect`
- `rust_2018_idioms`: no implicit lifetimes, which were present on
usages of `core::fmt::Formatter`
