Crates / proc-macro-error2
Rust crate · real downloads · data Oct 24, 2026
proc-macro-error2 downloads, and should you depend on it?
Almost drop-in replacement to panics in proc-macros crates.io · docs.rs · repository
Owned on crates.io by GnomedDev · alternatives · is it still maintained?
Feature flags + Cargo.toml picker · Security history
Established and losing ground.
proc-macro-error2: 103 crates depend on it; no release in the last 90 days, so its count is all steady use.
How this verdict is decided (4 rules)
- Usage: crates.io reverse dependencies (crates that list it as a dependency): 10,000+ = foundational, 1,000+ = widely used, 100+ = established, under 100 = few direct dependents.
- Direction: the median quiet day in the last 30 days of the window against the first 30, read against the median tracked crate (the whole field moved +39% from late summer to October, so a raw trend says nothing). 10%+ ahead of the field = gaining; 10%+ behind = losing ground; otherwise steady. Steady with no release in 2+ years = quiet for years.
- Release spikes: the median release-window day against the quiet-day baseline: under 1.15x = no spike, 1.15x to 1.3x = small bumps, 1.3x or more = jumps on release days.
- Release recency: days since the newest version that was not yanked, from crates.io publish times.
release window (release day + next day)quiet dayquiet-day median · download the 89 days as CSV
The numbers in one paragraphproc-macro-error2 got 38,675,194 crates.io downloads from Jul 27, 2026 to Oct 23, 2026 with no new version in that window, so every day is a quiet day: a median of 492,199 a day, about 3,445,393 a week. With no release spikes to remove, its whole count is the steady baseline.
What this means if you're choosing a dependency
- Used, not everywhere. 103 crates depend on it. Look at how fast its issues get answered before you lean on it.
- No release in 2.1 years (last: 2.0.1, Sep 6, 2024). Many small crates are simply done. Run
cargo auditto check for known advisories before you depend on it. - Fit check: license MIT OR Apache-2.0, edition 2021, needs Rust 1.61 or newer (from the latest version's manifest).
- Its raw count is a fair read. Under 1% of its downloads in the window came from release windows, so the raw number and the baseline (492,199 a day) tell the same story.
Alternatives that do a similar job
Crates that share its crates.io category or keywords, most similar first. Each line is the crate's own description, then how it compares on the same data.
Its place in the dependency graph
proc-macro-error2 builds on
Tracked crates its latest version (2.0.1) depends on (optional ones marked).
What the chart says
- Weekend quiet days ran at 50% of weekday quiet days (254,174 vs 503,896). A dip that deep is the signature of work-week CI pipelines and developers building on weekdays.
- Biggest day: 601,073 on Oct 22, 2026, a quiet day with no release nearby.
Every number
| All-time downloads | 167,054,407 (rank #669 on crates.io by all-time downloads) |
| Downloads in the window | 38,675,194 (Jul 27, 2026 to Oct 23, 2026, 89 days) |
| Within 2 days of a release | 0 (0.0%) |
| Quiet-day median (baseline) | 492,199 a day; weekdays 503,896, weekends 254,174 |
| Release-adjusted downloads | 38,675,194 (release-window days capped at the baseline) |
| Baseline rank | #685 of the 1000 crates we track |
| Quiet-day trend | -5% raw, -32% against the median tracked crate (+39%) |
| Releases in the window | 0 |
| Versions published, ever | 5 |
| Latest version | 2.0.1, published Sep 6, 2024 (license MIT OR Apache-2.0, edition 2021, MSRV 1.61) |
| First published | Aug 26, 2023 |
| Reverse dependencies | 103 |
How we compute this
crates.io counts every download, including CI runners, mirrors and bots that fetch each new version, so raw counts run high (why, in The Manual). We split the last 89 days into release windows (the day a version of proc-macro-error2 was published, plus the next day) and quiet days, and use the median quiet day as the baseline: an upper bound on steady use, never a head count. The method and data come from our study of 90 days of crates.io data from 69 crates, featured in This Week in Rust #674; check any crate live with the real-downloads checker.
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Categories
Sources
- Daily downloads: crates.io API, /crates/proc-macro-error2/downloads (last 90 days, all versions), fetched Oct 24, 2026.
- Versions and publish times: crates.io API, /crates/proc-macro-error2/versions, same fetch.
- Reverse dependencies: crates.io reverse dependencies, same fetch. Dependency edges between tracked crates: each crate's default version, crates.io API.
- Fetched politely (one request every 2 seconds, identified User-Agent) per the crates.io data access policy. Data is crates.io's; the release-window split, baseline and verdict rules are ours, CC BY 4.0.
Up next
Next in procedural macro helpers: Next in Procedural macro helpers by real downloads: 449,319 a day, 1,291 dependents. Widely used and steady.inventoryRust crate. Typed distributed plugin registration. Real use: 449K downloads a day on quiet days; 1,291 crates depend on it.Read it next →Also worth your time