ICE: diagnostics/mutability_errors.rs: index out of bounds

[matthiaskrgr]

auto-reduced (treereduce-rust):

trait Hello {
    fn example(val: T);
}

struct Test1(i32);

impl Hello for Test1 {
    fn example(&self, input: &i32) {
        *input = self.0;
    }
}

original:

trait Hello {
  fn example(val: T); // should suggest here
}

struct Test1(i32);

impl Hello for Test1 {
  fn example(&self, input: &i32) { // should not suggest here
      *input = self.0; //~ ERROR cannot assign
  }
}

struct Test2(i32);

impl Hello for Test2 {
  fn example(&self, input: &i32) { // should not suggest here
    self.0 += *input; //~ ERROR cannot assign
  }
}

fn main() { }

Version information

rustc 1.78.0-nightly (b381d3ab2 2024-02-12)
binary: rustc
commit-hash: b381d3ab27f788f990551100c4425bb782d26d76
commit-date: 2024-02-12
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 17.0.6

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

Program output

error[E0412]: cannot find type `T` in this scope
 --> /tmp/icemaker_global_tempdir.r53dfo7rqFNJ/rustc_testrunner_tmpdir_reporting.0vPBTfW1Hynm/mvce.rs:2:21
  |
2 |     fn example(val: T);
  |                     ^ not found in this scope

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.r53dfo7rqFNJ/rustc_testrunner_tmpdir_reporting.0vPBTfW1Hynm/mvce.rs:11:2
   |
11 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.r53dfo7rqFNJ/rustc_testrunner_tmpdir_reporting.0vPBTfW1Hynm/mvce.rs`

error[E0185]: method `example` has a `&self` declaration in the impl, but not in the trait
 --> /tmp/icemaker_global_tempdir.r53dfo7rqFNJ/rustc_testrunner_tmpdir_reporting.0vPBTfW1Hynm/mvce.rs:8:5
  |
2 |     fn example(val: T);
  |     ------------------- trait method declared without `&self`
...
8 |     fn example(&self, input: &i32) {
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `&self` used in impl

thread 'rustc' panicked at compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs:703:60:
index out of bounds: the len is 1 but the index is 1
stack backtrace:
   0:     0x7f211a988476 - std::backtrace_rs::backtrace::libunwind::trace::h3f288a3148e8bb15
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f211a988476 - std::backtrace_rs::backtrace::trace_unsynchronized::h7277353061928bc0
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f211a988476 - std::sys_common::backtrace::_print_fmt::hbf79f06a8c92ca0e
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f211a988476 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h0afd1ff8e38a8a84
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f211a9db030 - core::fmt::rt::Argument::fmt::h7f26a9b6a6522b09
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/core/src/fmt/rt.rs:142:9
   5:     0x7f211a9db030 - core::fmt::write::he7de9de816f98016
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f211a97bc6f - std::io::Write::write_fmt::h38e65bf4265dc66c
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/io/mod.rs:1854:15
   7:     0x7f211a988254 - std::sys_common::backtrace::_print::hf1424a842a74edeb
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f211a988254 - std::sys_common::backtrace::print::hbb43acdb160822bd
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f211a98b047 - std::panicking::default_hook::{{closure}}::h9c602a562527e529
  10:     0x7f211a98ada9 - std::panicking::default_hook::h9cb3bf5f6c73326f
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/panicking.rs:292:9
  11:     0x7f211775cfdc - std[73253c920228642]::panicking::update_hook::<alloc[940273873142bb35]::boxed::Box<rustc_driver_impl[f037f419b039420a]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f211a98b796 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h1e0fe9ec90d27cc3
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/alloc/src/boxed.rs:2030:9
  13:     0x7f211a98b796 - std::panicking::rust_panic_with_hook::hb5ad56797fd964c4
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/panicking.rs:785:13
  14:     0x7f211a98b4e2 - std::panicking::begin_panic_handler::{{closure}}::hd364aeee29433213
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/panicking.rs:659:13
  15:     0x7f211a988976 - std::sys_common::backtrace::__rust_end_short_backtrace::ha10bb1568b9ec73d
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7f211a98b234 - rust_begin_unwind
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/panicking.rs:647:5
  17:     0x7f211a9d7785 - core::panicking::panic_fmt::h91fa7152f33c7717
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/core/src/panicking.rs:72:14
  18:     0x7f211a9d79d2 - core::panicking::panic_bounds_check::h0d1f1f7efe646722
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/core/src/panicking.rs:208:5
  19:     0x7f211757016b - <rustc_borrowck[80a3d1af88a5539b]::MirBorrowckCtxt>::suggest_make_local_mut
  20:     0x7f2117044ba7 - <rustc_borrowck[80a3d1af88a5539b]::MirBorrowckCtxt>::report_mutability_error
  21:     0x7f211986556b - rustc_borrowck[80a3d1af88a5539b]::do_mir_borrowck
  22:     0x7f211981bb8f - rustc_borrowck[80a3d1af88a5539b]::mir_borrowck
  23:     0x7f211981b5d9 - rustc_query_impl[b78e7f0549dc02d3]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b78e7f0549dc02d3]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[dbb6cff8550fbced]::query::erase::Erased<[u8; 8usize]>>
  24:     0x7f2118b70bfa - rustc_query_system[74854bfa6cddafab]::query::plumbing::try_execute_query::<rustc_query_impl[b78e7f0549dc02d3]::DynamicConfig<rustc_query_system[74854bfa6cddafab]::query::caches::VecCache<rustc_span[a4806a91d128f927]::def_id::LocalDefId, rustc_middle[dbb6cff8550fbced]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[b78e7f0549dc02d3]::plumbing::QueryCtxt, false>
  25:     0x7f2118b70590 - rustc_query_impl[b78e7f0549dc02d3]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  26:     0x7f21193e0576 - rustc_interface[ceb207a8fb5539d]::passes::analysis
  27:     0x7f21193e005f - rustc_query_impl[b78e7f0549dc02d3]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b78e7f0549dc02d3]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[dbb6cff8550fbced]::query::erase::Erased<[u8; 1usize]>>
  28:     0x7f21198c6064 - rustc_query_system[74854bfa6cddafab]::query::plumbing::try_execute_query::<rustc_query_impl[b78e7f0549dc02d3]::DynamicConfig<rustc_query_system[74854bfa6cddafab]::query::caches::SingleCache<rustc_middle[dbb6cff8550fbced]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[b78e7f0549dc02d3]::plumbing::QueryCtxt, false>
  29:     0x7f21198c5dc7 - rustc_query_impl[b78e7f0549dc02d3]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7f21197409fb - rustc_interface[ceb207a8fb5539d]::interface::run_compiler::<core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>, rustc_driver_impl[f037f419b039420a]::run_compiler::{closure#0}>::{closure#0}
  31:     0x7f211996ef12 - std[73253c920228642]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[ceb207a8fb5539d]::util::run_in_thread_with_globals<rustc_interface[ceb207a8fb5539d]::util::run_in_thread_pool_with_globals<rustc_interface[ceb207a8fb5539d]::interface::run_compiler<core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>, rustc_driver_impl[f037f419b039420a]::run_compiler::{closure#0}>::{closure#0}, core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>>::{closure#0}, core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>>
  32:     0x7f211996ed3e - <<std[73253c920228642]::thread::Builder>::spawn_unchecked_<rustc_interface[ceb207a8fb5539d]::util::run_in_thread_with_globals<rustc_interface[ceb207a8fb5539d]::util::run_in_thread_pool_with_globals<rustc_interface[ceb207a8fb5539d]::interface::run_compiler<core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>, rustc_driver_impl[f037f419b039420a]::run_compiler::{closure#0}>::{closure#0}, core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>>::{closure#0}, core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[ed182bbac36ed604]::result::Result<(), rustc_span[a4806a91d128f927]::ErrorGuaranteed>>::{closure#1} as core[ed182bbac36ed604]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  33:     0x7f211a994985 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h37d86e7af57ec8cf
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/alloc/src/boxed.rs:2016:9
  34:     0x7f211a994985 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h99a2218ed45ac1ce
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/alloc/src/boxed.rs:2016:9
  35:     0x7f211a994985 - std::sys::pal::unix::thread::Thread::new::thread_start::h6344e9d30547345d
                               at /rustc/b381d3ab27f788f990551100c4425bb782d26d76/library/std/src/sys/pal/unix/thread.rs:108:17
  36:     0x7f21148749eb - <unknown>
  37:     0x7f21148f87cc - <unknown>
  38:                0x0 - <unknown>

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 1.78.0-nightly (b381d3ab2 2024-02-12) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [mir_borrowck] borrow-checking `<impl at /tmp/icemaker_global_tempdir.r53dfo7rqFNJ/rustc_testrunner_tmpdir_reporting.0vPBTfW1Hynm/mvce.rs:7:1: 7:21>::example`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 3 previous errors

Some errors have detailed explanations: E0185, E0412, E0601.
For more information about an error, try `rustc --explain E0185`.

[matthiaskrgr]

#120550 cc @oli-obk

[jieyouxu]

@rustbot label +D-diagnostic-infra -needs-triage