A Rust module loaded with `#[path = "…"]` was found by its file's directory:
fast-mlsirm's `#[path = "../../../tests/unit/scaling_tests.rs"] mod tests;`
in `crates/core/src/scaling.rs` made `tests/unit/scaling_tests.rs`'s
`use super::*` walk to a `tests/unit` module that doesn't exist, so its
`predict_rating_multi(1)` linked to nothing, or to a same-named function of
another crate; its `crate::` had no crate, and the parent's private items
looked out of its reach. From the declaring side, a path through such a
module (`utils::mock_event(…)` under `#[path = "./utils.rs"] mod utils;`)
reached nothing.
The fix reads each file's `#[path]` declarations as the Rust Reference
reads the attribute (from the declaring file's directory, or inside an
inline `mod` from that module's own; a path that leaves the project, by
escapesRoot, or that a `cfg_attr` sets, names no file):
- rustSubmodule: a module the module declares once with a `#[path]` is
the file it names, whatever else loads that file too (a helper several
tests load is each test's); cfg alternatives that name a file each stay
unknown, and a path's 2015 crate-root fallback no longer reaches past
such a module to a namesake at the crate root.
- rustPathClaim: a file the regular rules don't place is the module of the
one `#[path]` declaration that loads it, if exactly one does. Placed
(rustPlacedByName) are crate roots, files with a `fn main` or
`#![no_main]` of their own (trybuild cases, fuzz targets), and files a
plain `mod name;` declares in the module owning their directory or in an
inline module of one above it (dioxus's `mod components { pub mod home; }`
in main.rs). Only for a file left over are the project's Rust files that
write `path =` read (a byte check first), once per resolver. With a
claim, rustSuperModule is the declaring module, rustFileModule owns the
file's directory (rustc reads every `#[path]` file as a mod.rs),
rustCrateRootModule is the declaring file's crate, and rustModuleWithin,
isRustItemVisibleFrom and isVisibleAcrossFiles see the file inside the
declaring module, so `use super::*` brings in its private items.
- rustCrateGraph: `[[example]]`, `[[test]]` and `[[bench]]` paths are
target roots, as `[lib]`/`[[bin]]` ones are since PR #3014, and such an
example is its own crate's root (dioxus's
`examples/07-fullstack/handling_errors.rs`).
Validation:
- rust-path-super-glob.test.ts (PR 1892's case, credited) and
rust-path-attribute-modules.test.ts (7 cases): on main all 8 fail; all
pass. Every rust-* suite passes.
- A/B against main, native kernel: fast-mlsirm (its Rust files) +2,796
links (1,839 calls, 427 references, 334 constructions, 196 imports), 71
retargeted (exposure_tests.rs's `Lcg::next_f64` from cdm_tests.rs's
private `Lcg` to exposure.rs's, the declaring module's helpers instead
of bifactor_grm.rs's), 87 reaching the same item through the declaring
module (confidence 0.4 to 0.9), 0 removed; dioxus +27 (each headless
test's `utils::mock_event(…)` into the helper five tests load); tokio +2
(`use super::AtomicU64` in the files atomic_u64_as_mutex.rs loads);
ripgrep, axum, clap, serde, gleam, express and flask unchanged.
- Cost, native kernel, medians of 3 interleaved runs: fast-mlsirm CPU 15.3
-> 15.8 s, wall 4.2 -> 5.2 s, peak RSS 825 -> 882 MB; tokio CPU 26.1 ->
26.7 s, wall 10.4 -> 11.2 s, peak RSS 1,023 -> 1,028 MB; dioxus CPU 34.8
-> 35.6 s, wall 10.3 -> 11.2 s, peak RSS 1,125 -> 1,120 MB; gleam CPU
24.1 -> 23.8 s, wall 6.6 -> 6.7 s, peak RSS 1,027 -> 1,023 MB.
Builds on PR #1892 by @seonghobae.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
