Unexpected doc path collision with combination of workspace, proc-macro, explicit target and optimizations

[PonasKovas]

Problem

In these specific conditions (workspace with a proc-macro, building for a specific target with optimizations) cargo doc fails with an error that doesn't make any sense.

> cargo doc
error: document output filename collision
The lib `b` in package `b v0.1.0 (doc-collision-minimal/b)` has the same name as the lib `b` in package `b v0.1.0 (doc-collision-minimal/b)`.
Only one may be documented at once since they output to the same path.
Consider documenting only one, renaming one, or marking one with `doc = false` in Cargo.toml.

Tried on the latest nightly 1.85.0-nightly (917bfa784 2024-12-26) and the current stable 1.83.0 (5ffbef321 2024-10-29)

Steps

• Workspace with 2 crates: a and b.
  • a depends on b, which is a proc-macro.
• Compile with optimizations enabled (any opt-level except 0)
• Specify an explicit target (e.g. x86_64-unknown-linux-musl)

Possible Solution(s)

No response

Notes

Minimal reproducible example

Version

cargo 1.85.0-nightly (c86f4b3a1 2024-12-24)
release: 1.85.0-nightly
commit-hash: c86f4b3a1b153218e6e50861214b0b4b4e695f23
commit-date: 2024-12-24
host: x86_64-unknown-linux-gnu
libgit2: 1.8.1 (sys:0.19.0 vendored)
libcurl: 8.9.0-DEV (sys:0.4.74+curl-8.9.0 vendored ssl:OpenSSL/1.1.1w)
ssl: OpenSSL 1.1.1w  11 Sep 2023
os: Arch Linux Rolling Release [64-bit]

[PonasKovas]

Oops, this appears to be a duplicate of #10368

[weihanglo]

Thanks. Close in favor of #10368.