Internal Compiler Error when building an async closure that calls methods on a referenced variable and a cloned referenced variable in a specific order #123697
Description
Code
This bug only happens when calling a method on two different referenced variables inside an async closure. For some reason, this bug will not happen if the lines are flipped (calling it on test first then temp). It also will not happen if test isn't cloned outside the closure first.
This will error:
#![feature(async_closure, async_fn_traits)] fn main() {} pub fn test(test: &u64, temp: &u64) { let test = test.clone(); async || { temp.abs_diff(12); test.clone(); }; }This will not:
pub fn test(test: &u64, temp: &u64) { async || { temp.abs_diff(12); test.clone(); }; }Neither will:
pub fn test(test: &u64, temp: &u64) { let test = test.clone(); async || { test.clone(); temp.abs_diff(12); }; }Nor will:
pub fn test(test: &u64, temp: &u64) { let temp = temp.clone(); async || { test.clone(); temp.abs_diff(12); }; }But if both the order is flipped and the line order is flipped it will crash (variable name changed to make sure shadowing wasn't the issue):
pub fn test(test: &u64, temp: &u64) { let other = test.clone(); async || { temp.clone(); other.abs_diff(12); }; }This setup for the bug was found entirely through trial and error. The original issue was found in a nightly build of a project I'm working on (https://github.com/BigBadE/Raven-Language/actions/runs/8608806965/job/23628381189).
Meta
This bug was introduced in the latest version of nightly (2024-04-08). It was not present in 2024-04-07.
rustc 1.79.0-nightly (ab5bda1 2024-04-08)
binary: rustc
commit-hash: ab5bda1
commit-date: 2024-04-08
host: x86_64-pc-windows-msvc
release: 1.79.0-nightly
LLVM version: 18.1.3
Error output
$ cargo build Compiling testing v0.1.0 (D:\RustProjects\testing) thread 'rustc' panicked at compiler\rustc_mir_transform\src\coroutine\by_move_body.rs:159:17: assertion failed: child_capture.place.projections.len() >= parent_capture.place.projections.len() stack backtrace: 0: 0x7ff8165537fa - std::backtrace_rs::backtrace::dbghelp64::trace at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\..\..\backtrace\src\backtrace\dbghelp64.rs:99 1: 0x7ff8165537fa - std::backtrace_rs::backtrace::trace_unsynchronized at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66 2: 0x7ff8165537fa - std::sys_common::backtrace::_print_fmt at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\sys_common\backtrace.rs:68 3: 0x7ff8165537fa - std::sys_common::backtrace::_print::impl$0::fmt at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\sys_common\backtrace.rs:44 4: 0x7ff8165845e9 - core::fmt::rt::Argument::fmt at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\core\src\fmt\rt.rs:142 5: 0x7ff8165845e9 - core::fmt::write at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\core\src\fmt\mod.rs:1153 6: 0x7ff816549fd1 - std::io::Write::write_fmt<std::sys::pal::windows::stdio::Stderr> at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\io\mod.rs:1843 7: 0x7ff8165535e6 - std::sys_common::backtrace::print at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\sys_common\backtrace.rs:34 8: 0x7ff8165567f8 - std::panicking::default_hook::closure$1 at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\panicking.rs:271 9: 0x7ff81655643a - std::panicking::default_hook at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\panicking.rs:291 10: 0x7fffd42bb030 - __longjmp_internal 11: 0x7ff816556e3c - alloc::boxed::impl$50::call at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\alloc\src\boxed.rs:2032 12: 0x7ff816556e3c - std::panicking::rust_panic_with_hook at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\panicking.rs:792 13: 0x7ff816556c8b - std::panicking::begin_panic_handler::closure$0 at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\panicking.rs:649 14: 0x7ff81655410f - std::sys_common::backtrace::__rust_end_short_backtrace<std::panicking::begin_panic_handler::closure_env$0,never$> at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\sys_common\backtrace.rs:171 15: 0x7ff816556978 - std::panicking::begin_panic_handler at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\panicking.rs:645 16: 0x7ff8165acae7 - core::panicking::panic_fmt at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\core\src\panicking.rs:72 17: 0x7ff8165acbc0 - core::panicking::panic at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\core\src\panicking.rs:141 18: 0x7fffd323ecd2 - <rustc_mir_transform[b373b9de80ff07e8]::coroutine::by_move_body::ByMoveBody as rustc_middle[84b64d630b2bee13]::mir::MirPass>::run_pass 19: 0x7fffd322fa9c - <rustc_mir_transform[b373b9de80ff07e8]::simplify::SimplifyCfg as rustc_middle[84b64d630b2bee13]::mir::MirPass>::run_pass 20: 0x7fffd32c0c9d - rustc_mir_transform[b373b9de80ff07e8]::mir_built 21: 0x7fffd392193a - rustc_query_impl[33a1b4098950561d]::plumbing::query_key_hash_verify_all 22: 0x7fffd3875c1a - rustc_traits[a53074f1b4e9ea87]::type_op::type_op_prove_predicate 23: 0x7fffd2b22cfe - rustc_query_impl[33a1b4098950561d]::query_system 24: 0x7fffd29ca496 - rustc_ty_utils[c3d756d018202afc]::ty::adt_sized_constraint 25: 0x7fffd35d220a - <rustc_mir_build[4c126c57b954b35a]::check_unsafety::UnsafetyVisitor as rustc_middle[84b64d630b2bee13]::thir::visit::Visitor>::visit_expr 26: 0x7fffd29ca58e - rustc_ty_utils[c3d756d018202afc]::ty::adt_sized_constraint 27: 0x7fffd35d220a - <rustc_mir_build[4c126c57b954b35a]::check_unsafety::UnsafetyVisitor as rustc_middle[84b64d630b2bee13]::thir::visit::Visitor>::visit_expr 28: 0x7fffd35d1563 - <rustc_mir_build[4c126c57b954b35a]::check_unsafety::UnsafetyVisitor as rustc_middle[84b64d630b2bee13]::thir::visit::Visitor>::visit_block 29: 0x7fffd35d329d - <rustc_mir_build[4c126c57b954b35a]::check_unsafety::UnsafetyVisitor as rustc_middle[84b64d630b2bee13]::thir::visit::Visitor>::visit_expr 30: 0x7fffd35d220a - <rustc_mir_build[4c126c57b954b35a]::check_unsafety::UnsafetyVisitor as rustc_middle[84b64d630b2bee13]::thir::visit::Visitor>::visit_expr 31: 0x7fffd35d3f90 - rustc_mir_build[4c126c57b954b35a]::check_unsafety::check_unsafety 32: 0x7fffd39205ca - rustc_query_impl[33a1b4098950561d]::plumbing::query_key_hash_verify_all 33: 0x7fffd386aa5a - rustc_traits[a53074f1b4e9ea87]::type_op::type_op_prove_predicate 34: 0x7fffd39292ab - rustc_query_impl[33a1b4098950561d]::plumbing::query_key_hash_verify_all 35: 0x7fffd2ef45a4 - <rustc_interface[f65115e9a3f8b78a]::passes::LintStoreExpandImpl as rustc_expand[90c53b689c18a18c]::base::LintStoreExpand>::pre_expansion_lint 36: 0x7fffd2b1a86a - <dyn std[edc18776cd067f9d]::io::Write as nu_ansi_term[730eb3389a53a735]::write::AnyWrite>::write_str 37: 0x7fffd2a3a6c9 - rustc_traits[a53074f1b4e9ea87]::type_op::type_op_normalize_clause 38: 0x7fffd2b1fe13 - rustc_query_impl[33a1b4098950561d]::query_system 39: 0x7fffcfef2fd9 - __ImageBase 40: 0x7fffcfef0337 - __ImageBase 41: 0x7fffcfef8a89 - __ImageBase 42: 0x7ff8165678ed - alloc::boxed::impl$48::call_once at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\alloc\src\boxed.rs:2018 43: 0x7ff8165678ed - alloc::boxed::impl$48::call_once at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\alloc\src\boxed.rs:2018 44: 0x7ff8165678ed - std::sys::pal::windows::thread::impl$0::new::thread_start at /rustc/ab5bda1aa70f707014e2e691e43bc37a8819252a/library\std\src\sys\pal\windows\thread.rs:53 45: 0x7ff85a297344 - BaseThreadInitThunk 46: 0x7ff85b4c26b1 - RtlUserThreadStart error: the compiler unexpectedly panicked. this is a bug. note: it seems that this compiler `1.79.0-nightly (ab5bda1aa 2024-04-08)` is outdated, a newer nightly should have been released in the meantime | = note: please consider running `rustup update nightly` to update the nightly channel and check if this problem still persists = note: if the problem still persists, 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: please attach the file at `...` to your bug report note: compiler flags: --crate-type bin -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED] note: some of the compiler flags provided by cargo are hidden query stack during panic: #0 [mir_built] building MIR for `test::{closure#0}::{closure#0}` #1 [check_unsafety] unsafety-checking `test` #2 [analysis] running analysis passes on this crate end of query stack error: could not compile `testing` (bin "testing")``` ICE txt file: [rustc-ice-2024-04-09T21_28_12-2316.txt](https://github.com/rust-lang/rust/files/14924081/rustc-ice-2024-04-09T21_28_12-2316.txt)