New stabilized APIs for pattern matching assertions and NonZero range iteration reduce boilerplate in match-heavy code; Cargo now permits git+registry dual specs per dependency.
Summary
assert_matches! eliminates custom test helpers for assertion patterns; NonZero range iteration avoids unsafe conversions in type-safe loops. Dual git/registry specs in Cargo resolve publish workflows that require different sources locally vs. on crates.io.
Why it matters
assert_matches! eliminates custom test helpers for assertion patterns; NonZero range iteration avoids unsafe conversions in type-safe loops. Dual git/registry specs in Cargo resolve publish workflows that require different sources locally vs. on crates.io.
Implementation verdict
assert_matches! replaces hand-rolled macro patterns immediately—use now. NonZero ranges enable safer numeric code without friction. Cargo dual-spec requires no config changes but unblocks mixed-source dependency strategies. All three are ready for production use.
Sources
Dev Signal
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