Found unstable fingerprints for def_ident_span

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),
                    ],
                )))
            }
        }
    }
}

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

@Aaron1011

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.

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 ?

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..

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

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.

@rustbot

@rustbot claim

Rollup merge of rust-lang#161099 - zakrad:regr-test-95945, r=folkertdev

Unrolled build for #161099

Rollup merge of #161099 - zakrad:regr-test-95945, r=folkertdev

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Found unstable fingerprints for `def_ident_span` #95945

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Found unstable fingerprints for def_ident_span #95945

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lqd commented on Apr 12, 2022

lqd commented on Apr 13, 2022

jessa0 commented on Apr 13, 2022

lqd commented on Apr 13, 2022

Aaron1011 commented on Apr 13, 2022

zakrad commented on Aug 13, 2026

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Found unstable fingerprints for `def_ident_span` #95945