cargo test --doc silently fails with --target x86_64-unknown-linux-musl

[WildCryptoFox]

src.rs

//! ```
//! assert_eq!(1 + 1, 2);
//! ```

cargo test --doc; echo rc=$?

   Compiling hello-world v0.1.0 (hello-world)
    Finished dev [unoptimized + debuginfo] target(s) in 0.37s
     Running target/debug/deps/hello-world-4720fc1f96669b3c

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests aaa

running 1 test
test src/lib.rs -  (line 1) ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

rc=0

cargo test --doc --target x86_64-unknown-linux-musl; echo rc=$?

   Compiling hello-world v0.1.0 (hello-world)
    Finished dev [unoptimized + debuginfo] target(s) in 0.12s
rc=0

[ehuss]

I think this is a known issue. See #31907, #44404, and rust-lang/cargo#6460.

[ehuss]

Closing in favor of the tracking issues #64245 and rust-lang/cargo#7040.