Found unstable fingerprints for `def_ident_span`

[jessa0]

Recompiling this minimal example using rustc 1.60.0 (7737e0b5c 2022-04-04) or rustc 1.62.0-nightly (1f7fb6413 2022-04-10) crashes with Found unstable fingerprints for def_ident_span(foo[c936]::{impl#0}::deserialize::{impl#0}::One): Some(src/lib.rs:5:5: 5:8 (#0)):

Code

Since this is an incremental compilation bug, there are "before" and "after" code snippets, where a cargo build happens on the "before" snippet and then on the "after" snippet.

Before

Unexpanded:

#[derive(serde_repr::Deserialize_repr)]
#[repr(u32)]
pub enum DownloadUrlVersion {
    One = 1,
}

Expanded (via cargo-expand):

#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2018::*;
#[macro_use]
extern crate std;
#[repr(u32)]
pub enum DownloadUrlVersion {
    One = 1,
}
impl<'de> serde::Deserialize<'de> for DownloadUrlVersion {
    #[allow(clippy::use_self)]
    fn deserialize<D>(deserializer: D) -> core::result::Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        struct discriminant;
        #[allow(non_upper_case_globals)]
        impl discriminant {
            const One: u32 = DownloadUrlVersion::One as u32;
        }
        match <u32 as serde::Deserialize>::deserialize(deserializer)? {
            discriminant::One => core::result::Result::Ok(DownloadUrlVersion::One),
            other => {
                core::result::Result::Err(serde::de::Error::custom(::core::fmt::Arguments::new_v1(
                    &["invalid value: ", ", expected "],
                    &[
                        ::core::fmt::ArgumentV1::new_display(&other),
                        ::core::fmt::ArgumentV1::new_display(&discriminant::One),
                    ],
                )))
            }
        }
    }
}

After

Unexpanded:

#[derive(serde_repr::Deserialize_repr)]
#[repr(u32)]
pub enum DownloadUrlVersion {
    Zero = 0,
    One = 1,
}

Expanded (via cargo-expand):

#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2018::*;
#[macro_use]
extern crate std;
#[repr(u32)]
pub enum DownloadUrlVersion {
    Zero = 0,
    One = 1,
}
impl<'de> serde::Deserialize<'de> for DownloadUrlVersion {
    #[allow(clippy::use_self)]
    fn deserialize<D>(deserializer: D) -> core::result::Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        struct discriminant;
        #[allow(non_upper_case_globals)]
        impl discriminant {
            const Zero: u32 = DownloadUrlVersion::Zero as u32;
            const One: u32 = DownloadUrlVersion::One as u32;
        }
        match <u32 as serde::Deserialize>::deserialize(deserializer)? {
            discriminant::Zero => core::result::Result::Ok(DownloadUrlVersion::Zero),
            discriminant::One => core::result::Result::Ok(DownloadUrlVersion::One),
            other => {
                core::result::Result::Err(serde::de::Error::custom(::core::fmt::Arguments::new_v1(
                    &["invalid value: ", ", expected ", " or "],
                    &[
                        ::core::fmt::ArgumentV1::new_display(&other),
                        ::core::fmt::ArgumentV1::new_display(&discriminant::Zero),
                        ::core::fmt::ArgumentV1::new_display(&discriminant::One),
                    ],
                )))
            }
        }
    }
}

Meta

rustc --version --verbose:

rustc 1.60.0 (7737e0b5c 2022-04-04)
binary: rustc
commit-hash: 7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c
commit-date: 2022-04-04
host: aarch64-apple-darwin
release: 1.60.0
LLVM version: 14.0.0

rustc +nightly --version --verbose:

rustc 1.62.0-nightly (1f7fb6413 2022-04-10)
binary: rustc
commit-hash: 1f7fb6413d6d6c0c929b223e478e44c3db991b03
commit-date: 2022-04-10
host: aarch64-apple-darwin
release: 1.62.0-nightly
LLVM version: 14.0.0

Error output

Before

$ cargo clean
$ cargo build --verbose
   Compiling proc-macro2 v1.0.37
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.91
   Compiling serde v1.0.136
     Running `rustc --crate-name unicode_xid /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/unicode-xid-0.2.2/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="default"' -C metadata=b192d4f04adf99f3 -C extra-filename=-b192d4f04adf99f3 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --cap-lints allow`
     Running `rustc --crate-name build_script_build /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.136/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="std"' -C metadata=a145d8193496760a -C extra-filename=-a145d8193496760a --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/build/serde-a145d8193496760a -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --cap-lints allow`
     Running `rustc --crate-name build_script_build --edition=2018 /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.37/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="proc-macro"' -C metadata=54d91ef164e76c4d -C extra-filename=-54d91ef164e76c4d --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/build/proc-macro2-54d91ef164e76c4d -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --cap-lints allow`
     Running `rustc --crate-name build_script_build --edition=2018 /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/syn-1.0.91/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="clone-impls"' --cfg 'feature="default"' --cfg 'feature="derive"' --cfg 'feature="parsing"' --cfg 'feature="printing"' --cfg 'feature="proc-macro"' --cfg 'feature="quote"' -C metadata=adb216cdad43cf6d -C extra-filename=-adb216cdad43cf6d --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/build/syn-adb216cdad43cf6d -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --cap-lints allow`
     Running `/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/build/serde-a145d8193496760a/build-script-build`
     Running `/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/build/syn-adb216cdad43cf6d/build-script-build`
     Running `/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/build/proc-macro2-54d91ef164e76c4d/build-script-build`
     Running `rustc --crate-name serde /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.136/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="std"' -C metadata=d1f7947ec26ea969 -C extra-filename=-d1f7947ec26ea969 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --cap-lints allow`
     Running `rustc --crate-name proc_macro2 --edition=2018 /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.37/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="proc-macro"' -C metadata=4e08bce1730af525 -C extra-filename=-4e08bce1730af525 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern unicode_xid=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libunicode_xid-b192d4f04adf99f3.rmeta --cap-lints allow --cfg use_proc_macro --cfg wrap_proc_macro`
   Compiling quote v1.0.18
     Running `rustc --crate-name quote --edition=2018 /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/quote-1.0.18/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="proc-macro"' -C metadata=c3e7bab2f9655afa -C extra-filename=-c3e7bab2f9655afa --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern proc_macro2=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libproc_macro2-4e08bce1730af525.rmeta --cap-lints allow`
     Running `rustc --crate-name syn --edition=2018 /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/syn-1.0.91/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 --cfg 'feature="clone-impls"' --cfg 'feature="default"' --cfg 'feature="derive"' --cfg 'feature="parsing"' --cfg 'feature="printing"' --cfg 'feature="proc-macro"' --cfg 'feature="quote"' -C metadata=c4dc7608567cfc8e -C extra-filename=-c4dc7608567cfc8e --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern proc_macro2=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libproc_macro2-4e08bce1730af525.rmeta --extern quote=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libquote-c3e7bab2f9655afa.rmeta --extern unicode_xid=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libunicode_xid-b192d4f04adf99f3.rmeta --cap-lints allow --cfg syn_disable_nightly_tests`
   Compiling serde_repr v0.1.7
     Running `rustc --crate-name serde_repr --edition=2018 /Users/jessa/.cargo/registry/src/github.com-1ecc6299db9ec823/serde_repr-0.1.7/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type proc-macro --emit=dep-info,link -C prefer-dynamic -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C metadata=1dfbf050e1c9e8b7 -C extra-filename=-1dfbf050e1c9e8b7 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern proc_macro2=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libproc_macro2-4e08bce1730af525.rlib --extern quote=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libquote-c3e7bab2f9655afa.rlib --extern syn=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libsyn-c4dc7608567cfc8e.rlib --extern proc_macro --cap-lints allow`
   Compiling foo v0.1.0 (/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101)
     Running `rustc --crate-name foo --edition=2018 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C metadata=c859f0c5874eceb8 -C extra-filename=-c859f0c5874eceb8 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -C incremental=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/incremental -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern serde=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libserde-d1f7947ec26ea969.rmeta --extern serde_repr=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libserde_repr-1dfbf050e1c9e8b7.dylib`
    Finished dev [unoptimized + debuginfo] target(s) in 2.79s

After

$ RUSTC_BACKTRACE=1 cargo build --verbose
       Fresh unicode-xid v0.2.2
       Fresh proc-macro2 v1.0.37
       Fresh quote v1.0.18
       Fresh serde v1.0.136
       Fresh syn v1.0.91
       Fresh serde_repr v0.1.7
   Compiling foo v0.1.0 (/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101)
     Running `rustc --crate-name foo --edition=2018 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C metadata=c859f0c5874eceb8 -C extra-filename=-c859f0c5874eceb8 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -C incremental=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/incremental -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern serde=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libserde-d1f7947ec26ea969.rmeta --extern serde_repr=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libserde_repr-1dfbf050e1c9e8b7.dylib`
error: internal compiler error: encountered incremental compilation error with def_ident_span(foo[368a]::{impl#0}::deserialize::{impl#0}::One)
  |
  = help: This is a known issue with the compiler. Run `cargo clean -p foo` or `cargo clean` to allow your project to compile
  = note: Please follow the instructions below to create a bug report with the provided information
  = note: See <https://github.com/rust-lang/rust/issues/84970> for more information

thread 'rustc' panicked at 'Found unstable fingerprints for def_ident_span(foo[368a]::{impl#0}::deserialize::{impl#0}::One): Some(src/lib.rs:5:5: 5:8 (#0))', compiler/rustc_query_system/src/query/plumbing.rs:657:9
stack backtrace:
... see below ...

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.60.0 (7737e0b5c 2022-04-04) running on aarch64-apple-darwin

note: compiler flags: --crate-type lib -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [def_ident_span] looking up span for `<impl at src/lib.rs:1:10: 1:38>::deserialize::<impl at src/lib.rs:1:10: 1:38>::One`'s identifier
#1 [typeck] type-checking `<impl at src/lib.rs:1:10: 1:38>::deserialize`
#2 [typeck_item_bodies] type-checking all item bodies
#3 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `foo` due to previous error

Caused by:
  process didn't exit successfully: `rustc --crate-name foo --edition=2018 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C metadata=c859f0c5874eceb8 -C extra-filename=-c859f0c5874eceb8 --out-dir /Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps -C incremental=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/incremental -L dependency=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps --extern serde=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libserde-d1f7947ec26ea969.rmeta --extern serde_repr=/Users/jessa/.emacs.d/rust-playground/at-2022-04-11-105101/target/debug/deps/libserde_repr-1dfbf050e1c9e8b7.dylib` (exit status: 101)

Backtrace

thread 'rustc' panicked at 'Found unstable fingerprints for def_ident_span(foo[368a]::{impl#0}::deserialize::{impl#0}::One): Some(src/lib.rs:5:5: 5:8 (#0))', compiler/rustc_query_system/src/query/plumbing.rs:657:9
stack backtrace:
   0:        0x103527118 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h10cf06316d33e2a9
   1:        0x103573808 - core::fmt::write::h1faf18c959c3a8df
   2:        0x103519104 - std::io::Write::write_fmt::h86ab231360bc97d2
   3:        0x10352ae44 - std::panicking::default_hook::{{closure}}::h36e628ffaf3cd44f
   4:        0x10352aabc - std::panicking::default_hook::h3ee1564a7544e58f
   5:        0x10a9005c4 - rustc_driver[3e35567b0507961a]::DEFAULT_HOOK::{closure#0}::{closure#0}
   6:        0x10352b634 - std::panicking::rust_panic_with_hook::h191339fbd2fe2360
   7:        0x10352b388 - std::panicking::begin_panic_handler::{{closure}}::h91c230befd9929e3
   8:        0x103527600 - std::sys_common::backtrace::__rust_end_short_backtrace::haaaeebb1d37476b3
   9:        0x10352b0c4 - _rust_begin_unwind
  10:        0x1035a17fc - core::panicking::panic_fmt::h4fe1013b011ef602
  11:        0x10e814198 - rustc_query_system[91d58cadb6adb151]::query::plumbing::incremental_verify_ich_cold
  12:        0x10d701584 - rustc_query_system[91d58cadb6adb151]::query::plumbing::incremental_verify_ich::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_span[dd8cd730fd24a84e]::def_id::DefId, core[e180da0f2c78f25f]::option::Option<rustc_span[dd8cd730fd24a84e]::span_encoding::Span>>
  13:        0x10d6d881c - rustc_query_system[91d58cadb6adb151]::query::plumbing::try_load_from_disk_and_cache_in_memory::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_span[dd8cd730fd24a84e]::def_id::DefId, core[e180da0f2c78f25f]::option::Option<rustc_span[dd8cd730fd24a84e]::span_encoding::Span>>
  14:        0x10d696ae4 - rustc_query_system[91d58cadb6adb151]::query::plumbing::try_execute_query::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_query_system[91d58cadb6adb151]::query::caches::DefaultCache<rustc_span[dd8cd730fd24a84e]::def_id::DefId, core[e180da0f2c78f25f]::option::Option<rustc_span[dd8cd730fd24a84e]::span_encoding::Span>>>
  15:        0x10d7252fc - rustc_query_system[91d58cadb6adb151]::query::plumbing::get_query::<rustc_query_impl[9309ed91bf96ef41]::queries::def_ident_span, rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt>
  16:        0x10e3d9f4c - <rustc_middle[48a4de8117124789]::ty::assoc::AssocItem>::ident
  17:        0x10e3dab10 - <rustc_middle[48a4de8117124789]::ty::assoc::AssocItems>::find_by_name_and_namespace
  18:        0x10cd2d354 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::associated_value
  19:        0x10cd95088 - <rustc_typeck[761806a90de36c46]::check::method::probe::ProbeContext>::impl_or_trait_item
  20:        0x10cd90654 - <rustc_typeck[761806a90de36c46]::check::method::probe::ProbeContext>::assemble_inherent_impl_probe
  21:        0x10cd90518 - <rustc_typeck[761806a90de36c46]::check::method::probe::ProbeContext>::assemble_inherent_impl_candidates_for_type
  22:        0x10cd8fa48 - <rustc_typeck[761806a90de36c46]::check::method::probe::ProbeContext>::assemble_inherent_candidates
  23:        0x10ce29aa0 - <rustc_infer[85aec4995fa1aeb4]::infer::InferCtxt>::probe::<core[e180da0f2c78f25f]::result::Result<rustc_typeck[761806a90de36c46]::check::method::probe::Pick, rustc_typeck[761806a90de36c46]::check::method::MethodError>, <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::probe_op<<rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::probe_for_name::{closure#0}, rustc_typeck[761806a90de36c46]::check::method::probe::Pick>::{closure#4}>
  24:        0x10cd498f0 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::probe_for_name
  25:        0x10cd4bcb0 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::resolve_fully_qualified_call
  26:        0x10cd159e8 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::resolve_ty_and_res_fully_qualified_call
  27:        0x10cd4c484 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::check_pat
  28:        0x10cd3db80 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::check_match
  29:        0x10cd0aa50 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  30:        0x10cd1aefc - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::check_block_with_expected
  31:        0x10cd0aa50 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  32:        0x10cd0b6d0 - <rustc_typeck[761806a90de36c46]::check::fn_ctxt::FnCtxt>::check_return_expr
  33:        0x10cefd5cc - rustc_typeck[761806a90de36c46]::check::check::check_fn
  34:        0x10ce16c80 - <rustc_infer[85aec4995fa1aeb4]::infer::InferCtxtBuilder>::enter::<&rustc_middle[48a4de8117124789]::ty::context::TypeckResults, <rustc_typeck[761806a90de36c46]::check::inherited::InheritedBuilder>::enter<rustc_typeck[761806a90de36c46]::check::typeck_with_fallback<rustc_typeck[761806a90de36c46]::check::typeck::{closure#0}>::{closure#1}, &rustc_middle[48a4de8117124789]::ty::context::TypeckResults>::{closure#0}>
  35:        0x10cdcd188 - rustc_typeck[761806a90de36c46]::check::typeck
  36:        0x10d89e320 - <rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepGraph<rustc_middle[48a4de8117124789]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[48a4de8117124789]::ty::context::TyCtxt, rustc_span[dd8cd730fd24a84e]::def_id::LocalDefId, &rustc_middle[48a4de8117124789]::ty::context::TypeckResults>
  37:        0x10d9f18a0 - rustc_data_structures[6a7bec35f5e261c6]::stack::ensure_sufficient_stack::<(&rustc_middle[48a4de8117124789]::ty::context::TypeckResults, rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepNodeIndex), rustc_query_system[91d58cadb6adb151]::query::plumbing::execute_job<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_span[dd8cd730fd24a84e]::def_id::LocalDefId, &rustc_middle[48a4de8117124789]::ty::context::TypeckResults>::{closure#3}>
  38:        0x10d6926bc - rustc_query_system[91d58cadb6adb151]::query::plumbing::try_execute_query::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_query_system[91d58cadb6adb151]::query::caches::DefaultCache<rustc_span[dd8cd730fd24a84e]::def_id::LocalDefId, &rustc_middle[48a4de8117124789]::ty::context::TypeckResults>>
  39:        0x10d760968 - rustc_query_system[91d58cadb6adb151]::query::plumbing::get_query::<rustc_query_impl[9309ed91bf96ef41]::queries::typeck, rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt>
  40:        0x10ce60c58 - <rustc_middle[48a4de8117124789]::hir::map::Map>::par_body_owners::<rustc_typeck[761806a90de36c46]::check::typeck_item_bodies::{closure#0}>
  41:        0x10cdd0cf4 - rustc_typeck[761806a90de36c46]::check::typeck_item_bodies
  42:        0x10d8d0fec - <rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepGraph<rustc_middle[48a4de8117124789]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[48a4de8117124789]::ty::context::TyCtxt, (), ()>
  43:        0x10d9f6224 - rustc_data_structures[6a7bec35f5e261c6]::stack::ensure_sufficient_stack::<((), rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepNodeIndex), rustc_query_system[91d58cadb6adb151]::query::plumbing::execute_job<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, (), ()>::{closure#3}>
  44:        0x10d6ca520 - rustc_query_system[91d58cadb6adb151]::query::plumbing::try_execute_query::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_query_system[91d58cadb6adb151]::query::caches::DefaultCache<(), ()>>
  45:        0x10d734004 - rustc_query_system[91d58cadb6adb151]::query::plumbing::get_query::<rustc_query_impl[9309ed91bf96ef41]::queries::typeck_item_bodies, rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt>
  46:        0x10cde1514 - <rustc_session[d383daeae0c11292]::session::Session>::time::<(), rustc_typeck[761806a90de36c46]::check_crate::{closure#7}>
  47:        0x10cdc27e0 - rustc_typeck[761806a90de36c46]::check_crate
  48:        0x10a9e6010 - rustc_interface[2280aded15839b11]::passes::analysis
  49:        0x10d8c7df0 - <rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepGraph<rustc_middle[48a4de8117124789]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[48a4de8117124789]::ty::context::TyCtxt, (), core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>
  50:        0x10d9e8a34 - rustc_data_structures[6a7bec35f5e261c6]::stack::ensure_sufficient_stack::<(core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepNodeIndex), rustc_query_system[91d58cadb6adb151]::query::plumbing::execute_job<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, (), core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#3}>
  51:        0x10d6c1464 - rustc_query_system[91d58cadb6adb151]::query::plumbing::try_execute_query::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_query_system[91d58cadb6adb151]::query::caches::DefaultCache<(), core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>>
  52:        0x10d760dc4 - rustc_query_system[91d58cadb6adb151]::query::plumbing::get_query::<rustc_query_impl[9309ed91bf96ef41]::queries::analysis, rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt>
  53:        0x10a8f3d38 - <rustc_interface[2280aded15839b11]::passes::QueryContext>::enter::<rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>
  54:        0x10a8a744c - rustc_interface[2280aded15839b11]::interface::create_compiler_and_run::<core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}>
  55:        0x10a88ecb0 - std[8541ff70ccfedbb0]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[2280aded15839b11]::util::run_in_thread_pool_with_globals<rustc_interface[2280aded15839b11]::interface::run_compiler<core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>
  56:        0x10a908648 - <<std[8541ff70ccfedbb0]::thread::Builder>::spawn_unchecked_<rustc_interface[2280aded15839b11]::util::run_in_thread_pool_with_globals<rustc_interface[2280aded15839b11]::interface::run_compiler<core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#1} as core[e180da0f2c78f25f]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  57:        0x103536b70 - std::sys::unix::thread::Thread::new::thread_start::h8ccdabc567c5eee0
  58:        0x1b5a35240 - __pthread_deallocate

[lqd]

Bisection points to #93095 for this, but it may be a different manifestation of the earlier issue the PR was supposed to fix ?
In any case, cc PR author @Aaron1011 and reviewer @cjgillot.

[lqd]

Since this repro depends on serde_repr, and in turn serde, syn, etc it would be good to have an MCVE so that we can turn it into a test ?

[jessa0]

Since this repro depends on serde_repr, and in turn serde, syn, etc it would be good to have an MCVE so that we can turn it into a test ?

Here's a minimal proc-macro-derive:

use proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, Data, DataEnum, DeriveInput};

#[proc_macro_derive(Bar)]
pub fn derive_bar(input: TokenStream) -> TokenStream {
    let DeriveInput { ident, data, .. } = parse_macro_input!(input as DeriveInput);
    match data {
        Data::Enum(DataEnum { variants, .. }) => {
            let constants = variants.iter().map(|variant| {
                quote! {
                    const #variant: () = ();
                }
            });
            quote! {
                impl #ident {
                    #(#constants)*
                }
            }
            .into()
        }
        _ => panic!(),
    }
}

And here's the code to compile incrementally (before):

#[derive(foo_macros::Bar)]
pub enum FooEnum { One }

and after:

#[derive(foo_macros::Bar)]
pub enum FooEnum { Zero, One }

I couldn't manage to reproduce it by just passing in idents to a regular proc-macro. I'm not sure how to best eliminate syn as a dependency..

[lqd]

Note: this issue was fixed by #95656 which will be available in tomorrow's nightly.

[Aaron1011]

I have a minimized test locally - unfortunately, ai don't think it can be made to work with the revision system. I work on converting to a run-make test that manually edits the file.