ice: failed: failed in format_file visitor.buffer

[matthiaskrgr]

!!! REQUIRES DEBUG ASSERTIONS !!!

#[no_mangle]
static FOO: () = ();

fn main() {
    extern "fail
" {
        fn FOO();
    }
    unsafe { FOO() } //~ ERROR: attempt to call an exported symbol that is not defined as a function
}

thread 'main' panicked at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/formatting.rs:227:9:
assertion `left == right` failed: failed in format_file visitor.buffer:
 "#[no_mangle]\nstatic FOO: () = ();\n\nfn main() {\n    extern \"fail\n\" {\n        fn FOO();\n    }\n    unsafe { FOO() } //~ ERROR: attempt to call an exported symbol that is not defined as a function\n}\n"
  left: 9
 right: 10
stack backtrace:
   0:     0x7fd18dd7ca5d - std::backtrace_rs::backtrace::libunwind::trace::hb28aaf5f3549701f
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7fd18dd7ca5d - std::backtrace_rs::backtrace::trace_unsynchronized::he4f17ec88b61fea5
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fd18dd7ca5d - std::sys_common::backtrace::_print_fmt::h5a82a3e85aa2fae5
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7fd18dd7ca5d - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hb03764486a25b659
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fd18ddc55cf - core::fmt::rt::Argument::fmt::h67bfbe6caf20ecda
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/fmt/rt.rs:142:9
   5:     0x7fd18ddc55cf - core::fmt::write::h2b3e0bd86bdfc209
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/fmt/mod.rs:1120:17
   6:     0x7fd18dd64285 - std::io::Write::write_fmt::hcf7284dad3d07738
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/io/mod.rs:1854:15
   7:     0x7fd18dd7c824 - std::sys_common::backtrace::_print::h1988031c6b9fcf4a
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7fd18dd7c824 - std::sys_common::backtrace::print::h81809c76434159ce
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7fd18dd4022c - std::panicking::default_hook::{{closure}}::he3de9259d121bac5
  10:     0x7fd18dd3ff00 - std::panicking::default_hook::hcde334a568bf04a2
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:292:9
  11:     0x7fd1908ffe47 - rustc_driver_impl[8889ac64fe77a2fe]::install_ice_hook::{closure#0}
                               at /home/matthias/vcs/github/rust_debug_assertions/compiler/rustc_driver_impl/src/lib.rs:1340:17
  12:     0x7fd1908ffe47 - <alloc[3b5cf733b6b27210]::boxed::Box<rustc_driver_impl[8889ac64fe77a2fe]::install_ice_hook::{closure#0}> as core[aa444211b5f41879]::ops::function::Fn<(&dyn for<'a, 'b> core[aa444211b5f41879]::ops::function::Fn<(&'a core[aa444211b5f41879]::panic::panic_info::PanicInfo<'b>,), Output = ()> + core[aa444211b5f41879]::marker::Sync + core[aa444211b5f41879]::marker::Send, &core[aa444211b5f41879]::panic::panic_info::PanicInfo)>>::call
                               at /home/matthias/vcs/github/rust_debug_assertions/library/alloc/src/boxed.rs:2029:9
  13:     0x7fd18dd40ae3 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h65cf345775a09bb6
                               at /home/matthias/vcs/github/rust_debug_assertions/library/alloc/src/boxed.rs:2029:9
  14:     0x7fd18dd40ae3 - std::panicking::rust_panic_with_hook::hb041b1849b056e6a
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:785:13
  15:     0x7fd18dd7cf1a - std::panicking::begin_panic_handler::{{closure}}::hae61001f490e889a
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:659:13
  16:     0x7fd18dd7cd26 - std::sys_common::backtrace::__rust_end_short_backtrace::h07aab78c7d5e7b18
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/sys_common/backtrace.rs:171:18
  17:     0x7fd18dd40654 - rust_begin_unwind
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:647:5
  18:     0x7fd18dddf965 - core::panicking::panic_fmt::h7cdaca6ac7987f65
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/panicking.rs:72:14
  19:     0x7fd18dde0019 - core::panicking::assert_failed_inner::heed625da7882381e
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/panicking.rs:337:23
  20:     0x55a6e03f112f - core[aa444211b5f41879]::panicking::assert_failed::<usize, usize>
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/panicking.rs:297:5
  21:     0x55a6e03f2227 - <rustfmt_nightly[fe4bb6d079290361]::formatting::FormatContext<rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>>::format_file
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/formatting.rs:227:9
  22:     0x55a6e03f2227 - rustfmt_nightly[fe4bb6d079290361]::formatting::format_project::<rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/formatting.rs:162:9
  23:     0x55a6e03e0955 - <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format_input_inner::{closure#0}
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/formatting.rs:48:33
  24:     0x55a6e03e0955 - <scoped_tls[af7c8664e9f149d3]::ScopedKey<rustc_span[9066a7c1991c4c44]::SessionGlobals>>::with::<<rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format_input_inner::{closure#0}, core[aa444211b5f41879]::result::Result<rustfmt_nightly[fe4bb6d079290361]::FormatReport, rustfmt_nightly[fe4bb6d079290361]::ErrorKind>>
                               at /home/matthias/.cargo/registry/src/index.crates.io-6f17d22bba15001f/scoped-tls-1.0.1/src/lib.rs:171:13
  25:     0x55a6e03ddf74 - rustc_span[9066a7c1991c4c44]::create_session_if_not_set_then::<core[aa444211b5f41879]::result::Result<rustfmt_nightly[fe4bb6d079290361]::FormatReport, rustfmt_nightly[fe4bb6d079290361]::ErrorKind>, <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format_input_inner::{closure#0}>::{closure#0}
                               at /home/matthias/vcs/github/rust_debug_assertions/compiler/rustc_span/src/lib.rs:151:50
  26:     0x55a6e03ddf74 - <scoped_tls[af7c8664e9f149d3]::ScopedKey<rustc_span[9066a7c1991c4c44]::SessionGlobals>>::set::<rustc_span[9066a7c1991c4c44]::create_session_if_not_set_then<core[aa444211b5f41879]::result::Result<rustfmt_nightly[fe4bb6d079290361]::FormatReport, rustfmt_nightly[fe4bb6d079290361]::ErrorKind>, <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format_input_inner::{closure#0}>::{closure#0}, core[aa444211b5f41879]::result::Result<rustfmt_nightly[fe4bb6d079290361]::FormatReport, rustfmt_nightly[fe4bb6d079290361]::ErrorKind>>
                               at /home/matthias/.cargo/registry/src/index.crates.io-6f17d22bba15001f/scoped-tls-1.0.1/src/lib.rs:137:9
  27:     0x55a6e03ec8af - rustc_span[9066a7c1991c4c44]::create_session_if_not_set_then::<core[aa444211b5f41879]::result::Result<rustfmt_nightly[fe4bb6d079290361]::FormatReport, rustfmt_nightly[fe4bb6d079290361]::ErrorKind>, <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format_input_inner::{closure#0}>
                               at /home/matthias/vcs/github/rust_debug_assertions/compiler/rustc_span/src/lib.rs:151:9
  28:     0x55a6e03e14c9 - <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format_input_inner
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/formatting.rs:38:9
  29:     0x55a6e03cec97 - <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::format
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/lib.rs:465:9
  30:     0x55a6e03cec97 - rustfmt[9b0bb1331446777d]::format_and_emit_report::<std[1ba472e493b6ecda]::io::stdio::Stdout>
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/bin/main.rs:371:19
  31:     0x55a6e03ddb76 - rustfmt[9b0bb1331446777d]::format::{closure#0}
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/bin/main.rs:343:21
  32:     0x55a6e03ddb76 - <rustfmt_nightly[fe4bb6d079290361]::Session<std[1ba472e493b6ecda]::io::stdio::Stdout>>::override_config::<rustfmt[9b0bb1331446777d]::format::{closure#0}, ()>
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/lib.rs:473:22
  33:     0x55a6e03cda17 - rustfmt[9b0bb1331446777d]::format
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/bin/main.rs:342:17
  34:     0x55a6e03cda17 - rustfmt[9b0bb1331446777d]::execute
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/bin/main.rs:257:14
  35:     0x55a6e03cb01a - rustfmt[9b0bb1331446777d]::main
                               at /home/matthias/vcs/github/rust_debug_assertions/src/tools/rustfmt/src/bin/main.rs:38:27
  36:     0x55a6e03e2dd3 - <fn() as core[aa444211b5f41879]::ops::function::FnOnce<()>>::call_once
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/ops/function.rs:250:5
  37:     0x55a6e03e2dd3 - std[1ba472e493b6ecda]::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/sys_common/backtrace.rs:155:18
  38:     0x55a6e03ee189 - std[1ba472e493b6ecda]::rt::lang_start::<()>::{closure#0}
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/rt.rs:166:18
  39:     0x7fd18dd402c7 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h297db2377758e0cf
                               at /home/matthias/vcs/github/rust_debug_assertions/library/core/src/ops/function.rs:284:13
  40:     0x7fd18dd402c7 - std::panicking::try::do_call::hae59afb433bdb921
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:554:40
  41:     0x7fd18dd402c7 - std::panicking::try::h35e373fc7666cc2e
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:518:19
  42:     0x7fd18dd402c7 - std::panic::catch_unwind::h46e79a28bdb63479
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panic.rs:142:14
  43:     0x7fd18dd402c7 - std::rt::lang_start_internal::{{closure}}::hf3e58066b1096274
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/rt.rs:148:48
  44:     0x7fd18dd402c7 - std::panicking::try::do_call::h100385e03aa55f9a
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:554:40
  45:     0x7fd18dd402c7 - std::panicking::try::h89b6326347797a0c
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panicking.rs:518:19
  46:     0x7fd18dd54ddb - std::panic::catch_unwind::h230c430ad70c1500
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/panic.rs:142:14
  47:     0x7fd18dd54ddb - std::rt::lang_start_internal::h2a6bfb497173e897
                               at /home/matthias/vcs/github/rust_debug_assertions/library/std/src/rt.rs:148:20
  48:     0x55a6e03cf8bc - main
  49:     0x7fd18dabacd0 - <unknown>
  50:     0x7fd18dabad8a - __libc_start_main
  51:     0x55a6e03b1cd5 - _start
  52:                0x0 - <unknown>

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

note: we would appreciate a bug report: https://github.com/rust-lang/rustfmt/issues/new?labels=bug

note: please attach the file at `/tmp/im/rustc-ice-2024-02-07T19_30_52-3961474.txt` to your bug report

query stack during panic:
end of query stack

[ytmimi]

!!! REQUIRES DEBUG ASSERTIONS !!!

@matthiaskrgr what version of rustfmt were you using and how can this be reproduced?

[matthiaskrgr]

I bootstrap my own rustc toolchain (from git repo) with debug assertions and use the resulting rustfmt binary 😅

commit of the rustc tree was d6c46a23ce19e910225abacc33bcca9d0f549148

[ytmimi]

Thanks for the info! I haven't had a chance to see why this is failing, but for now here's the location of where the issue is:

rustfmt/src/formatting.rs

Lines 227 to 232 in ead0fc9

	debug_assert_eq!(
	visitor.line_number,
	count_newlines(&visitor.buffer),
	"failed in format_file visitor.buffer:\n {:?}",
	&visitor.buffer
	);