ICE: un_derefer.rs: `index out of bounds: the len is 0 but the index is 0`

[matthiaskrgr]

auto-reduced (treereduce-rust):

trait T {}

type Alias<'a> = impl T;

struct S;
impl<'a> T for &'a S {}

fn with_positive(fun: impl Fn(Alias<'_>)) {
    with_positive(|&n| ());
}

original:

trait T {}

type Alias<'a> = impl T;

struct S;
impl<'a> T for &'a S {}

fn with_positive(fun: impl Fn(Alias<'_>)) {
    with_positive(|&n| ());
}

fn main(Alias<'_>) {
    with_positive(|&a| ());
}

Version information

rustc 1.79.0-nightly (b3df0d7e5 2024-03-22)
binary: rustc
commit-hash: b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87
commit-date: 2024-03-22
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.2

Command: /home/matthias/.rustup/toolchains/master/bin/rustc

Program output

``` error[E0658]: `impl Trait` in type aliases is unstable --> /tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs:3:18 | 3 | type Alias<'a> = impl T; | ^^^^^^ | = note: see issue #63063 for more information = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable = note: this compiler was built on 2024-03-22; consider upgrading it if it is out of date error[E0601]: `main` function not found in crate `mvce` --> /tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs:10:2 | 10 | } | ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs` warning: unused variable: `fun` --> /tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs:8:18 | 8 | fn with_positive(fun: impl Fn(Alias<'_>)) { | ^^^ help: if this is intentional, prefix it with an underscore: `_fun` | = note: `#[warn(unused_variables)]` on by default warning: function cannot return without recursing --> /tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs:8:1 | 8 | fn with_positive(fun: impl Fn(Alias<'_>)) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing 9 | with_positive(|&n| ()); | ---------------------- recursive call site | = help: a `loop` may express intention better if this is on purpose = note: `#[warn(unconditional_recursion)]` on by default warning: unused variable: `n` --> /tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs:9:21 | 9 | with_positive(|&n| ()); | ^ help: if this is intentional, prefix it with an underscore: `_n` error[E0507]: cannot move out of a shared reference --> /tmp/icemaker_global_tempdir.Y54EKqIXoWUB/rustc_testrunner_tmpdir_reporting.e4LbEvdE1kIj/mvce.rs:9:20 | 9 | with_positive(|&n| ()); | ^- | | | data moved here | move occurs because `n` has type `S`, which does not implement the `Copy` trait | help: consider removing the borrow | 9 - with_positive(|&n| ()); 9 + with_positive(|n| ()); | thread 'rustc' panicked at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/compiler/rustc_mir_dataflow/src/un_derefer.rs:67:20: index out of bounds: the len is 0 but the index is 0 stack backtrace: 0: 0x737eb0d9afa5 - std::backtrace_rs::backtrace::libunwind::trace::h4515e3e00f57996f at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5 1: 0x737eb0d9afa5 - std::backtrace_rs::backtrace::trace_unsynchronized::h1e64ac1112175e4e at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 2: 0x737eb0d9afa5 - std::sys_common::backtrace::_print_fmt::h182160b5ad873150 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/sys_common/backtrace.rs:68:5 3: 0x737eb0d9afa5 - ::fmt::h432843f19f8b2b6d at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/sys_common/backtrace.rs:44:22 4: 0x737eb0debfeb - core::fmt::rt::Argument::fmt::hb59bbd21accf1885 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/core/src/fmt/rt.rs:142:9 5: 0x737eb0debfeb - core::fmt::write::haf243cf4605e411d at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/core/src/fmt/mod.rs:1153:17 6: 0x737eb0d8fd3f - std::io::Write::write_fmt::hd8c8c68b4f5b8f11 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/io/mod.rs:1843:15 7: 0x737eb0d9ad7e - std::sys_common::backtrace::_print::h0ec933d6103e5515 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/sys_common/backtrace.rs:47:5 8: 0x737eb0d9ad7e - std::sys_common::backtrace::print::h55136fa64edb86e6 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/sys_common/backtrace.rs:34:9 9: 0x737eb0d9d9f9 - std::panicking::default_hook::{{closure}}::h28cbeefc01b40f52 10: 0x737eb0d9d763 - std::panicking::default_hook::h15e904210c67a3ca at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/panicking.rs:292:9 11: 0x737ead5cb6bf - std[48784e9e46568672]::panicking::update_hook::>::{closure#0} 12: 0x737eb0d9e150 - as core::ops::function::Fn>::call::had664932fcaf7f86 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/alloc/src/boxed.rs:2029:9 13: 0x737eb0d9e150 - std::panicking::rust_panic_with_hook::h9f23cc8a1f418825 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/panicking.rs:783:13 14: 0x737eb0d9dea6 - std::panicking::begin_panic_handler::{{closure}}::h6c297ce5a3207845 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/panicking.rs:657:13 15: 0x737eb0d9b469 - std::sys_common::backtrace::__rust_end_short_backtrace::h7e27b03308c1610a at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/sys_common/backtrace.rs:171:18 16: 0x737eb0d9dbd7 - rust_begin_unwind at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/panicking.rs:645:5 17: 0x737eb0de8486 - core::panicking::panic_fmt::hc62934eef5acbd79 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/core/src/panicking.rs:72:14 18: 0x737eb0de86a7 - core::panicking::panic_bounds_check::h2ec889bc6f79e4c6 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/core/src/panicking.rs:205:5 19: 0x737eabbd9ccc - ::run_pass::{closure#0}>>::gather_move 20: 0x737eabbc2e27 - ::run_pass 21: 0x737eaea01a0d - rustc_mir_transform[b03574829d5a714c]::pass_manager::run_passes_inner 22: 0x737eaf17dc4b - rustc_mir_transform[b03574829d5a714c]::mir_drops_elaborated_and_const_checked 23: 0x737eaf17d563 - rustc_query_impl[82a63e1d7cdec9a7]::plumbing::__rust_begin_short_backtrace::> 24: 0x737eaebfe82e - rustc_query_system[ee3912bf2a9f33a7]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[82a63e1d7cdec9a7]::plumbing::QueryCtxt, false> 25: 0x737eaebfe10c - rustc_query_impl[82a63e1d7cdec9a7]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace 26: 0x737eaeea1068 - rustc_interface[7ddcde71cf02e108]::passes::analysis 27: 0x737eaee9fe51 - rustc_query_impl[82a63e1d7cdec9a7]::plumbing::__rust_begin_short_backtrace::> 28: 0x737eaf7eb4a5 - rustc_query_system[ee3912bf2a9f33a7]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[82a63e1d7cdec9a7]::plumbing::QueryCtxt, false> 29: 0x737eaf7eb209 - rustc_query_impl[82a63e1d7cdec9a7]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace 30: 0x737eaf6870d9 - rustc_interface[7ddcde71cf02e108]::interface::run_compiler::, rustc_driver_impl[9e9e6466696ec967]::run_compiler::{closure#0}>::{closure#0} 31: 0x737eaf752399 - std[48784e9e46568672]::sys_common::backtrace::__rust_begin_short_backtrace::, rustc_driver_impl[9e9e6466696ec967]::run_compiler::{closure#0}>::{closure#0}, core[b4a1350c838fc0f9]::result::Result<(), rustc_span[9e6cb2d6f72e9bb4]::ErrorGuaranteed>>::{closure#0}, core[b4a1350c838fc0f9]::result::Result<(), rustc_span[9e6cb2d6f72e9bb4]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[b4a1350c838fc0f9]::result::Result<(), rustc_span[9e6cb2d6f72e9bb4]::ErrorGuaranteed>> 32: 0x737eaf7521c6 - <::spawn_unchecked_, rustc_driver_impl[9e9e6466696ec967]::run_compiler::{closure#0}>::{closure#0}, core[b4a1350c838fc0f9]::result::Result<(), rustc_span[9e6cb2d6f72e9bb4]::ErrorGuaranteed>>::{closure#0}, core[b4a1350c838fc0f9]::result::Result<(), rustc_span[9e6cb2d6f72e9bb4]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[b4a1350c838fc0f9]::result::Result<(), rustc_span[9e6cb2d6f72e9bb4]::ErrorGuaranteed>>::{closure#1} as core[b4a1350c838fc0f9]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 33: 0x737eb0da7919 - as core::ops::function::FnOnce>::call_once::h3e016c41180ed802 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/alloc/src/boxed.rs:2015:9 34: 0x737eb0da7919 - as core::ops::function::FnOnce>::call_once::hcf0716ba35a33b0c at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/alloc/src/boxed.rs:2015:9 35: 0x737eb0da7919 - std::sys::pal::unix::thread::Thread::new::thread_start::hd585680968d21553 at /rustc/b3df0d7e5ef5f7dbeeca3fb289c65680ad013f87/library/std/src/sys/pal/unix/thread.rs:108:17 36: 0x737eb0b4755a - 37: 0x737eb0bc4a3c - 38: 0x0 - error: 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 1.79.0-nightly (b3df0d7e5 2024-03-22) running on x86_64-unknown-linux-gnu query stack during panic: #0 [mir_drops_elaborated_and_const_checked] elaborating drops for `with_positive::{closure#0}` #1 [analysis] running analysis passes on this crate end of query stack error: aborting due to 3 previous errors; 3 warnings emitted Some errors have detailed explanations: E0507, E0601, E0658. For more information about an error, try `rustc --explain E0507`. ```

[matthiaskrgr]

120550