1.99 beta crater regression: unresolved import in doctest

[cyrgani]

log: https://crater-reports.s3.amazonaws.com/beta-1.99-5/1.99.0-beta.1/reg/lfchring-0.1.3/log.txt
reduction:

/// ```rust
/// use x::A;
/// ```
#[cfg(any(feature = "a", doc))]
pub struct A;

with Cargo.toml:

[package]
name = "x"
edition = "2024"

[features]
a = []

another instance of this is https://crater-reports.s3.amazonaws.com/beta-1.99-5/1.99.0-beta.1/reg/kolibrios-syscalls-0.2.0/log.txt
and also https://crater-reports.s3.amazonaws.com/beta-1.99-5/1.99.0-beta.1/reg/memory_pages-0.1.0/log.txt

[apiraino]

@cyrgani how did you reproduce this? I've tried running cargo test on the memory_pages crate to try building a repro but it didn't work. thanks :)

[cyrgani]

By running cargo t and replacing the body of errno_msg with String::new() to supress the unrelated pointer type mismatch error, I got the same failure as from the crater run.

[jnkel]

This is the same as #162245, where doctests under cfg(any(doc, false)) were not run.

[apiraino]

can then this be considered duplicate of #162245 (and maybe closed?)

[theemathas]

Bisection output:

searched toolchains 96eb6d756bb98a82ae056c384575ff059bf80e8f through 0844f35a32c98882d77e39da8c2a872ec74615cd


********************************************************************************
Regression in 26bfbf28f5f79dff333ce5a232f131b496ec9cfe
********************************************************************************

Attempting to search unrolled perf builds
Found commits ["8c664ff8", "6df2fbc2", "7632d19d", "6bfa38cd", "e1a576d7", "251940c7", "6e11d9b8", "9a963c85", "36c25ca2", "c78de63a", "68f92628", "7c0cf8d7"]
installing 8c664ff890194e55cf413b326e638c03b4a39353
rust-std-nightly-x86_64-unknown-linux-gnu: 31.14 MB / 31.14 MB [==================================================================================================================] 100.00 % 9.30 MB/s testing...
RESULT: 8c664ff890194e55cf413b326e638c03b4a39353, ===> Compile error
uninstalling 8c664ff890194e55cf413b326e638c03b4a39353

Regression in https://github.com/rust-lang/rust/commit/8c664ff890194e55cf413b326e638c03b4a39353. Note that if it is a legacy rollup build, it might be available in https://github.com/rust-lang-ci/rust/commit/8c664ff890194e55cf413b326e638c03b4a39353.
The PR introducing the regression in this rollup is #159014: [rustdoc] Do not take `doc(cfg())` into account when filter…

Regressed in #159014. cc @GuillaumeGomez (author), @Urgau (reviewer)