Unexpected message: "WARN rustc_metadata::locator no metadata found: incompatible metadata version found:"

[dalance]

Code

I tried this code:

use thiserror::Error;

#[derive(Error, Debug)]
pub enum Error {
    #[error("error")]
    Error,
}

fn main() {
    let err = Error::Error;
    dbg!(err);
}

with this Cargo.toml

[package]
name = "test"
version = "0.1.0"
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
thiserror = "1.0.30"

I expected to see this happen:

$ cargo clean && cargo +1.40.0 run && touch src/lib.rs && cargo +1.57.0 run
   Compiling proc-macro2 v1.0.34
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.82
   Compiling quote v1.0.10
   Compiling thiserror-impl v1.0.30
   Compiling thiserror v1.0.30
   Compiling test v0.1.0 (/home/hatta/work/repos/playground/test62)
    Finished dev [unoptimized + debuginfo] target(s) in 7.30s
     Running `target/debug/test`
[src/main.rs:11] err = Error
  13.10s user 1.63s system 200% cpu 7.336 total
   Compiling proc-macro2 v1.0.34
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.82
   Compiling quote v1.0.10
   Compiling thiserror-impl v1.0.30
   Compiling thiserror v1.0.30
   Compiling test v0.1.0 (/home/hatta/work/repos/playground/test62)
    Finished dev [unoptimized + debuginfo] target(s) in 6.34s
     Running `target/debug/test`
[src/main.rs:11] err = Error

Instead, this happened:

$ cargo clean && cargo +1.40.0 run && touch src/lib.rs && cargo +1.57.0 run
   Compiling proc-macro2 v1.0.34
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.82
   Compiling quote v1.0.10
   Compiling thiserror-impl v1.0.30
   Compiling thiserror v1.0.30
   Compiling test v0.1.0 (/home/hatta/work/repos/playground/test62)
    Finished dev [unoptimized + debuginfo] target(s) in 7.30s
     Running `target/debug/test`
[src/main.rs:11] err = Error
  13.10s user 1.63s system 200% cpu 7.336 total
   Compiling proc-macro2 v1.0.34
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.82
   Compiling quote v1.0.10
   Compiling thiserror-impl v1.0.30
   Compiling thiserror v1.0.30
   Compiling test v0.1.0 (/home/hatta/work/repos/playground/test62)
WARN rustc_metadata::locator no metadata found: incompatible metadata version found: '/home/hatta/work/repos/playground/test62/target/debug/deps/libthiserror_impl-fb3604e0cefc2e39.so'
    Finished dev [unoptimized + debuginfo] target(s) in 6.34s
     Running `target/debug/test`
[src/main.rs:11] err = Error

The unexpected message "WARN rustc_metadata::locator no metadata found: incompatible metadata version found:" is shown.

Version it worked on

It most recently worked on: Rust 1.56

$ cargo clean && cargo +1.40.0 run && touch src/lib.rs && cargo +1.56.0 run
   Compiling proc-macro2 v1.0.34
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.82
   Compiling quote v1.0.10
   Compiling thiserror-impl v1.0.30
   Compiling thiserror v1.0.30
   Compiling test v0.1.0 (/home/hatta/work/repos/playground/test62)
    Finished dev [unoptimized + debuginfo] target(s) in 7.95s
     Running `target/debug/test`
[src/main.rs:11] err = Error
  14.01s user 2.04s system 201% cpu 7.979 total
   Compiling proc-macro2 v1.0.34
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.82
   Compiling quote v1.0.10
   Compiling thiserror-impl v1.0.30
   Compiling thiserror v1.0.30
   Compiling test v0.1.0 (/home/hatta/work/repos/playground/test62)
    Finished dev [unoptimized + debuginfo] target(s) in 6.81s
     Running `target/debug/test`
[src/main.rs:11] err = Error

Version with regression

rustc --version --verbose:

rustc 1.57.0 (f1edd0429 2021-11-29)
binary: rustc
commit-hash: f1edd0429582dd29cccacaf50fd134b05593bd9c
commit-date: 2021-11-29
host: x86_64-unknown-linux-gnu
release: 1.57.0
LLVM version: 13.0.0

Backtrace

Backtrace

<backtrace>

[dalance]

This may be related to #91935, but this is not ICE.

[ehuss]

Thanks for the report!

This has been fixed in 1.58 via #90544. I'm going to close as fixed as this only affects 1.57. @Mark-Simulacrum please reopen if you want this considered for a point release, otherwise I don't think there is much we can do.

[Mark-Simulacrum]

Yeah, that seems like the right thing. I'm not inclined to try to push out a point release right now.