ICE in teensy4-fcb 0.3.0: error during interning should later cause validation failure

[saethlin]

I'm downloading this crate from crates.io with cargo-download, if you are looking to reproduce. Don't know what git commit this version corresponds to.

╭ ➜ ben@archlinux:/tmp/teensy4-fcb-0.3.0
╰ ➤ cargo +miri miri test
Preparing a sysroot for Miri (target: x86_64-unknown-linux-gnu)... done
   Compiling teensy4-fcb v0.3.0 (/tmp/teensy4-fcb-0.3.0)
warning: Error finalizing incremental compilation session directory `/tmp/teensy4-fcb-0.3.0/target/miri/x86_64-unknown-linux-gnu/debug/incremental/teensy4_fcb-av1fopa54ky2/s-gcxx4h92b7-gdl6q4-working`: No such file or directory (os error 2)

error: internal compiler error: no errors encountered even though `delay_span_bug` issued

error: internal compiler error: error during interning should later cause validation failure: accessing memory with alignment 1, but alignment 4 is required
   --> src/lib.rs:102:1
    |
102 | const COMMON_CONFIGURATION_BLOCK: flexspi::ConfigurationBlock =
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: delayed at compiler/rustc_const_eval/src/interpret/intern.rs:390:30

error: internal compiler error: error during interning should later cause validation failure: accessing memory with alignment 1, but alignment 4 is required
   --> src/lib.rs:120:1
    |
120 | pub static FLEXSPI_CONFIGURATION_BLOCK: nor::ConfigurationBlock =
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: delayed at compiler/rustc_const_eval/src/interpret/intern.rs:390:30

I have no idea how this is possible. This isn't a #![forbid(unsafe)] crate, but cargo geiger finds no unsafe.

backtrace

``` thread 'rustc' panicked at 'Box', compiler/rustc_errors/src/lib.rs:1427:13 stack backtrace: 0: 0x7fe89716e6d0 - std::backtrace_rs::backtrace::libunwind::trace::h850ff1a0c3d9fdd7 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 1: 0x7fe89716e6d0 - std::backtrace_rs::backtrace::trace_unsynchronized::hb027726a633b9940 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 2: 0x7fe89716e6d0 - std::sys_common::backtrace::_print_fmt::h5caab733d2f6988a at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/sys_common/backtrace.rs:66:5 3: 0x7fe89716e6d0 - ::fmt::hdde469ef2c900889 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/sys_common/backtrace.rs:45:22 4: 0x7fe8971c976e - core::fmt::write::h652f9c882cd915d6 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/core/src/fmt/mod.rs:1202:17 5: 0x7fe89715f5d5 - std::io::Write::write_fmt::hc86f310f58407a21 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/io/mod.rs:1672:15 6: 0x7fe897171393 - std::sys_common::backtrace::_print::he3151b9612f2cb1c at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/sys_common/backtrace.rs:48:5 7: 0x7fe897171393 - std::sys_common::backtrace::print::h4ec5b0bf2cf6801f at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/sys_common/backtrace.rs:35:9 8: 0x7fe897171393 - std::panicking::default_hook::{{closure}}::h0eea56e2b7a0583d at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/panicking.rs:295:22 9: 0x7fe89717107f - std::panicking::default_hook::h9faf2b89120c3ca0 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/panicking.rs:314:9 10: 0x7fe8999ab494 - rustc_driver[8170f2effe76d0b1]::DEFAULT_HOOK::{closure#0}::{closure#0} 11: 0x7fe897171bcd - std::panicking::rust_panic_with_hook::h41881d4c2e288663 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/panicking.rs:702:17 12: 0x7fe89aa6d5d1 - std[6176ebdb849c2141]::panicking::begin_panic::::{closure#0} 13: 0x7fe89aa6d586 - std[6176ebdb849c2141]::sys_common::backtrace::__rust_end_short_backtrace::::{closure#0}, !> 14: 0x7fe89aa67dd6 - std[6176ebdb849c2141]::panicking::begin_panic:: 15: 0x7fe89aa6a596 - std[6176ebdb849c2141]::panic::panic_any:: 16: 0x7fe89948b230 - ::drop 17: 0x7fe8990e9db8 - core[ca3ac0430488f954]::ptr::drop_in_place:: 18: 0x7fe8990c00c3 - as core[ca3ac0430488f954]::ops::drop::Drop>::drop 19: 0x7fe8990bf62d - core[ca3ac0430488f954]::ptr::drop_in_place:: 20: 0x7fe8990bead9 - rustc_span[3aa3f8a4aae1164f]::with_source_map::, rustc_interface[3d10aad4a167cf18]::interface::create_compiler_and_run, rustc_driver[8170f2effe76d0b1]::run_compiler::{closure#1}>::{closure#1}> 21: 0x7fe8990be302 - rustc_interface[3d10aad4a167cf18]::interface::create_compiler_and_run::, rustc_driver[8170f2effe76d0b1]::run_compiler::{closure#1}> 22: 0x7fe8990bcea1 - >::set::, rustc_driver[8170f2effe76d0b1]::run_compiler::{closure#1}>::{closure#0}, core[ca3ac0430488f954]::result::Result<(), rustc_errors[28a60eca1a08eed5]::ErrorGuaranteed>> 23: 0x7fe8990bcb8f - std[6176ebdb849c2141]::sys_common::backtrace::__rust_begin_short_backtrace::, rustc_driver[8170f2effe76d0b1]::run_compiler::{closure#1}>::{closure#0}, core[ca3ac0430488f954]::result::Result<(), rustc_errors[28a60eca1a08eed5]::ErrorGuaranteed>>::{closure#0}, core[ca3ac0430488f954]::result::Result<(), rustc_errors[28a60eca1a08eed5]::ErrorGuaranteed>> 24: 0x7fe8997d42c9 - <::spawn_unchecked_, rustc_driver[8170f2effe76d0b1]::run_compiler::{closure#1}>::{closure#0}, core[ca3ac0430488f954]::result::Result<(), rustc_errors[28a60eca1a08eed5]::ErrorGuaranteed>>::{closure#0}, core[ca3ac0430488f954]::result::Result<(), rustc_errors[28a60eca1a08eed5]::ErrorGuaranteed>>::{closure#1} as core[ca3ac0430488f954]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 25: 0x7fe89717b9c3 - as core::ops::function::FnOnce>::call_once::h20aa7f83790b6d6c at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/alloc/src/boxed.rs:1935:9 26: 0x7fe89717b9c3 - as core::ops::function::FnOnce>::call_once::h082931b1ec2f572d at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/alloc/src/boxed.rs:1935:9 27: 0x7fe89717b9c3 - std::sys::unix::thread::Thread::new::thread_start::h5e56cc2c93616735 at /rustc/e1b28cd2f16bd5b832183d7968cae3bb9213e78d/library/std/src/sys/unix/thread.rs:108:17 28: 0x7fe896dfa78d - 29: 0x7fe896e7b8e4 - clone 30: 0x0 -

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 1.65.0-nightly (e1b28cd 2022-08-19) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2 -C linker=clang -C incremental -C link-arg=-fuse-ld=mold

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

query stack during panic:
end of query stack
warning: teensy4-fcb (lib) generated 1 warning
error: could not compile teensy4-fcb; 1 warning emitted

</details>

miri 0.1.0 (d5853bc 2022-08-25)

[RalfJung]

That's not even a Miri ICE, it's a rustc ICE. Probably caused by -Zextra-const-ub-checks -- I expect it can be reproduced without Miri by using that flag.

[saethlin]

Ah yes! I just couldn't get this to ICE with just cargo +nightly check but with -Zextra-const-ub-checks it does.

[RalfJung]

I am pretty sure #101038 should fix the problem. But I have no idea how to even trigger it in a self-contained testcase.