proc macro server crashed

[NickNick]

rust-analyzer version: b824588 2021-05-17 stable

After rustup update and maybe a new version of ra I get this error: 'proc macro returned error: proc-macro panicked: range end index 8 out of range for slice of length 0'.
stack backtrace:

thread 'main' panicked at 'range end index 8 out of range for slice of length 0', crates/proc_macro_srv/src/proc_macro/bridge/rpc.rs:135:1
stack backtrace:
   0: rust_begin_unwind
             at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53/library/core/src/panicking.rs:92:14
   2: core::slice::index::slice_end_index_len_fail
             at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53/library/core/src/slice/index.rs:41:5
   3: <proc_macro_srv::proc_macro::bridge::server::Dispatcher<proc_macro_srv::proc_macro::bridge::server::MarkedTypes<S>> as proc_macro_srv::proc_macro::bridge::server::DispatcherTrait>::dispatch
   4: <proc_macro_srv::proc_macro::bridge::closure::Closure<A,R> as core::convert::From<&mut F>>::from::call
   5: proc_macro::bridge::closure::Closure<A,R>::call
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/closure.rs:27:18
   6: proc_macro::bridge::client::Literal::integer::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:244:25
   7: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::with::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:336:47
   8: proc_macro::bridge::client::BridgeState::with::{{closure}}::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:293:17
   9: proc_macro::bridge::scoped_cell::ScopedCell<T>::replace
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/scoped_cell.rs:75:9
  10: proc_macro::bridge::client::BridgeState::with::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:291:13
  11: std::thread::local::LocalKey<T>::try_with
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/thread/local.rs:400:16
  12: std::thread::local::LocalKey<T>::with
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/thread/local.rs:376:9
  13: proc_macro::bridge::client::BridgeState::with
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:290:9
  14: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::with
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:329:9
  15: proc_macro::bridge::client::Literal::integer
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:237:17
  16: proc_macro::Literal::i64_unsuffixed
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/lib.rs:1006:21
  17: proc_macro2::imp::Literal::i64_unsuffixed
             at /home/nick/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.27/src/wrapper.rs:798:56
  18: proc_macro2::Literal::i64_unsuffixed
             at /home/nick/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.27/src/lib.rs:1045:41
  19: syn::expr::printing::<impl quote::to_tokens::ToTokens for syn::expr::Index>::to_tokens
             at /home/nick/.cargo/registry/src/github.com-1ecc6299db9ec823/syn-1.0.72/src/expr.rs:3287:27
  20: derive_more::add_helpers::tuple_exprs
             at /home/nick/.cargo/registry/src/github.com-1ecc6299db9ec823/derive_more-0.99.14/src/add_helpers.rs:11:20
  21: derive_more::add_assign_like::expand
             at /home/nick/.cargo/registry/src/github.com-1ecc6299db9ec823/derive_more-0.99.14/src/add_assign_like.rs:21:17
  22: derive_more::add_assign_derive
             at /home/nick/.cargo/registry/src/github.com-1ecc6299db9ec823/derive_more-0.99.14/src/lib.rs:280:29
  23: core::ops::function::FnOnce::call_once
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/core/src/ops/function.rs:227:5
  24: proc_macro::bridge::client::Client<fn(proc_macro::TokenStream) .> proc_macro::TokenStream>::expand1::run::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:410:40
  25: proc_macro::bridge::client::run_client::{{closure}}::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:377:26
  26: proc_macro::bridge::scoped_cell::ScopedCell<T>::set::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/scoped_cell.rs:80:33
  27: proc_macro::bridge::scoped_cell::ScopedCell<T>::replace
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/scoped_cell.rs:75:9
  28: proc_macro::bridge::scoped_cell::ScopedCell<T>::set
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/scoped_cell.rs:80:9
  29: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::enter::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:325:35
  30: std::thread::local::LocalKey<T>::try_with
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/thread/local.rs:400:16
  31: std::thread::local::LocalKey<T>::with
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/thread/local.rs:376:9
  32: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::enter
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:325:9
  33: proc_macro::bridge::client::run_client::{{closure}}
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:370:9
  34: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/panic.rs:346:9
  35: std::panicking::try::do_call
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/panicking.rs:401:40
  36: __rust_try
  37: std::panicking::try
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/panicking.rs:365:19
  38: std::panic::catch_unwind
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/std/src/panic.rs:433:14
  39: proc_macro::bridge::client::run_client
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:369:5
  40: proc_macro::bridge::client::Client<fn(proc_macro::TokenStream) .> proc_macro::TokenStream>::expand1::run
             at /rustc/5dc8789e300930751a78996da0fa906be5a344a2/library/proc_macro/src/bridge/client.rs:410:13
  41: proc_macro_srv::proc_macro::bridge::server::<impl proc_macro_srv::proc_macro::bridge::client::Client<fn(proc_macro_srv::proc_macro::bridge::client::TokenStream) .> proc_macro_srv::proc_macro::bridge::client::TokenStream>>::run
  42: proc_macro_srv::cli::run
  43: rust_analyzer::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread panicked while processing panic. aborting.
[ERROR proc_macro_api::process] proc macro server crashed, server process state: Ok(Some(ExitStatus(ExitStatus(132)))), server request error: Os { code: 32, kind: BrokenPipe, message: "Broken pipe" 

Here's a minimal example: https://github.com/NickNick/ra-proc-macro-panic-derivemore-from

For me it looks like this:

... but runs fine:

nick@fusrodah /m/d/c/ra-proc-macro (main)> cargo r
warning: field is never read: `leg`
 --> src/main.rs:4:5
  |
4 |     leg: &'a str,
  |     ^^^^^^^^^^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: 1 warning emitted

    Finished dev [unoptimized + debuginfo] target(s) in 0.00s
     Running `target/debug/ra-proc-macro`
Hello, world!

[lnicola]

Works for me in rustc 1.54.0-nightly (5c0292654 2021-05-11), fails in rustc 1.54.0-nightly (5dc8789e3 2021-05-21).

The proc macro ABI strikes again.

[ivan]

For the confused (like me), this is not caused by building rust-analyzer with nightly, but rather your own project.

The last working version is nightly-2021-05-20 and the first failing version is nightly-2021-05-21.

[ctaggart]

Thanks @ivan. rustup default stable did the trick. 😅

[gilescope]

The solution is not to use nightly???

[lnicola]

Or to disable proc macro support.

[gilescope]

Turning proc macros off works. I've seen this on quite a few projects now. This seems a pretty widespread regression. Maybe proc macro should default to off for the moment as it could give a bad impression to new users - seeing a sea of red and them thinking they've done something wrong?

[lnicola]

I would assume that most new users aren't running nightly.

[gilescope]

For one reason or another, an awful lot of people are on nightly and their take away will be that something's up with RA because they're building fine with cargo. I think you're all doing a great job, I'm just concerned that this bug (rightly or wrongly) is making RA look flaky to a fair section of your userbase.

[flodiebold]

Disabling proc macros completely would have a far greater impact.

[adsick]

Hi guys, i'm getting this proc macro server crash... with my Rocket project, could you please tell me how to disable proc macros (i'm using VSCode)

[adsick]

ok, I figured it out