./x build compiler --stage 0 reports success, but it shouldn't: deleting method used in another crate does not cause compilation to fail

[safinaskar]

./x build compiler --stage 0 reports success, but it shouldn't: deleting method used in another crate does not cause compilation to fail.

Okay, I found bug in ./x. If I delete a method in compiler source code, then ./x build compiler --stage 0 executes successfully. But it shouldn't, because this method is used in another compiler's crate.

Steps to reproduce (on x86_64 Linux):

• Clone the compiler: git clone --depth=1 https://github.com/rust-lang/rust
• Run cd rust
• Run cp config.example.toml config.toml
• Run ./x build library (this command will execute successfully)
• Edit file compiler/rustc_ast/src/token.rs: comment function pub fn is_like_plus
• Run ./x build compiler --stage 0, this command will succeed. But it shouldn't, because is_like_plus is used in another crate!
• Run ./x build library. This command will correctly fail

I found this bug when attempting to contribute to rustc. So this bug presents minor contributor roadblock, so I mark it so.

I used current HEAD, i. e. aea4e43 .

The bug seems to be related to #134916 .

@rustbot label A-contributor-roadblock T-bootstrap C-bug

[jieyouxu]

I can reproduce on HEAD, indeed, building it once then deleting a fn that should cause build to fail does not:

[00:06] Joe:rust (fresh *) | ./x build compiler --stage 0
Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.01s
Building stage0 library artifacts (x86_64-unknown-linux-gnu)
    Finished `release` profile [optimized + debuginfo] target(s) in 0.01s
Building compiler artifacts {rustc_abi} (stage0 -> stage1, x86_64-unknown-linux-gnu)
   Compiling rustc_abi v0.0.0 (/home/joe/repos/rust/compiler/rustc_abi)
    Finished `release` profile [optimized + debuginfo] target(s) in 0.17s
Build completed successfully in 0:00:00