ICE: interpret const eval failure of Unevaluated(UnevaluatedConst .. which is not in required_consts

[matthiaskrgr]

auto-reduced (treereduce-rust):

struct A<T: 'static>(&'static T);
struct B<T: ?Sized + Send> {
    x: &'static T,
}
static STR: &'static [u8] = "a b";
static C: A<B<B<[u8]>>> = { A(&B { x: &B { x: STR } }) };

original:

//@ run-pass

// Use of global static variables in literal values should be allowed for
// promotion.
// This test is to demonstrate the issue raised in
// https://github.com/rust-lang/rust/issues/70584

// Literal values were previously promoted into local static values when
// other global static variables are used.

struct A<T: 'static>(&'static T);
struct B<T: ?Sized + Send> {
    x: &'static T
}
static STR: &'static [u8] = "\x7Ba\x7D \x7Bb\x7D";
static C: A<B<B<[u8]>>> = {
    A(&B {
        x: &B { x: STR },
    })
};

pub struct Slice(&'static [i32]);

static CONTENT: i32 = 42;
pub static CONTENT_MAP: Slice = Slice(&[CONTENT]);

pub static FOO: (i32, i32) = (42, 43);
pub static CONTENT_MAP2: Slice = Slice(&[FOO.0]);

fn main() {
    assert_eq!(b"hi", C.0.x.x);
    assert_eq!(&[42], CONTENT_MAP.0);
    assert_eq!(&[42], CONTENT_MAP2.0);
}

Version information

rustc 1.85.0-nightly (acf48426b 2024-12-06)
binary: rustc
commit-hash: acf48426b64d24f372d534f634072de1f4c7e588
commit-date: 2024-12-06
host: x86_64-unknown-linux-gnu
release: 1.85.0-nightly
LLVM version: 19.1.5

Possibly related line of code:

rust/compiler/rustc_const_eval/src/interpret/eval_context.rs

Lines 588 to 600 in acf4842

	if reported.is_allowed_in_infallible() {
	// These errors can just sometimes happen, even when the expression
	// is nominally "infallible", e.g. when running out of memory
	// or when some layout could not be computed.
	} else {
	// Looks like the const is not captured by `required_consts`, that's bad.
	span_bug!(span, "interpret const eval failure of {val:?} which is not in required_consts");
	}
	}
	}
	}
	err.emit_note(*ecx.tcx);
	err

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

Program output

warning: unnecessary braces around assigned value
 --> /tmp/icemaker_global_tempdir.xOeHTpmH6ZfT/rustc_testrunner_tmpdir_reporting.M0zB4QRO8XGI/mvce.rs:6:27
  |
6 | static C: A<B<B<[u8]>>> = { A(&B { x: &B { x: STR } }) };
  |                           ^^                          ^^
  |
  = note: `#[warn(unused_braces)]` on by default
help: remove these braces
  |
6 - static C: A<B<B<[u8]>>> = { A(&B { x: &B { x: STR } }) };
6 + static C: A<B<B<[u8]>>> = A(&B { x: &B { x: STR } });
  |

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.xOeHTpmH6ZfT/rustc_testrunner_tmpdir_reporting.M0zB4QRO8XGI/mvce.rs:6:58
  |
6 | static C: A<B<B<[u8]>>> = { A(&B { x: &B { x: STR } }) };
  |                                                          ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.xOeHTpmH6ZfT/rustc_testrunner_tmpdir_reporting.M0zB4QRO8XGI/mvce.rs`

error[E0310]: the parameter type `T` may not live long enough
 --> /tmp/icemaker_global_tempdir.xOeHTpmH6ZfT/rustc_testrunner_tmpdir_reporting.M0zB4QRO8XGI/mvce.rs:3:8
  |
3 |     x: &'static T,
  |        ^^^^^^^^^^
  |        |
  |        the parameter type `T` must be valid for the static lifetime...
  |        ...so that the reference type `&'static T` does not outlive the data it points at
  |
help: consider adding an explicit lifetime bound
  |
2 | struct B<T: ?Sized + Send + 'static> {
  |                           +++++++++

error[E0308]: mismatched types
 --> /tmp/icemaker_global_tempdir.xOeHTpmH6ZfT/rustc_testrunner_tmpdir_reporting.M0zB4QRO8XGI/mvce.rs:5:29
  |
5 | static STR: &'static [u8] = "a b";
  |                             ^^^^^ expected `&[u8]`, found `&str`
  |
  = note: expected reference `&'static [u8]`
             found reference `&'static str`
help: consider adding a leading `b`
  |
5 | static STR: &'static [u8] = b"a b";
  |                             +

error: internal compiler error: compiler/rustc_const_eval/src/interpret/eval_context.rs:594:33: interpret const eval failure of Unevaluated(UnevaluatedConst { def: DefId(0:11 ~ mvce[d812]::C), args: [], promoted: Some(promoted[0]) }, &'{erased} B<B<[u8]>>) which is not in required_consts
 --> /tmp/icemaker_global_tempdir.xOeHTpmH6ZfT/rustc_testrunner_tmpdir_reporting.M0zB4QRO8XGI/mvce.rs:6:31
  |
6 | static C: A<B<B<[u8]>>> = { A(&B { x: &B { x: STR } }) };
  |                               ^^^^^^^^^^^^^^^^^^^^^^^

thread 'rustc' panicked at compiler/rustc_const_eval/src/interpret/eval_context.rs:594:33:
Box<dyn Any>
stack backtrace:
   0:     0x73bca0f4895a - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h69edfa39ad21a03a
   1:     0x73bca1613e26 - core::fmt::write::h54afaacea6c2c9e2
   2:     0x73bca25f3ad1 - std::io::Write::write_fmt::h00e73f8f3070368c
   3:     0x73bca0f487b2 - std::sys::backtrace::BacktraceLock::print::h2b0900033e71643f
   4:     0x73bca0f4acca - std::panicking::default_hook::{{closure}}::h325b3b03f2ea7a39
   5:     0x73bca0f4ab13 - std::panicking::default_hook::haaf25a6e7afde799
   6:     0x73bca00c1238 - std[85c61899f894cf29]::panicking::update_hook::<alloc[98b3c20953f4fbe5]::boxed::Box<rustc_driver_impl[45224e78b6d2fe59]::install_ice_hook::{closure#0}>>::{closure#0}
   7:     0x73bca0f4b488 - std::panicking::rust_panic_with_hook::hdc045113cf0fafba
   8:     0x73bca00f6771 - std[85c61899f894cf29]::panicking::begin_panic::<rustc_errors[2297728cd06420b6]::ExplicitBug>::{closure#0}
   9:     0x73bca00eb916 - std[85c61899f894cf29]::sys::backtrace::__rust_end_short_backtrace::<std[85c61899f894cf29]::panicking::begin_panic<rustc_errors[2297728cd06420b6]::ExplicitBug>::{closure#0}, !>
  10:     0x73bca00eb6d3 - std[85c61899f894cf29]::panicking::begin_panic::<rustc_errors[2297728cd06420b6]::ExplicitBug>
  11:     0x73bca0100711 - <rustc_errors[2297728cd06420b6]::diagnostic::BugAbort as rustc_errors[2297728cd06420b6]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x73bca0655d3c - <rustc_errors[2297728cd06420b6]::DiagCtxtHandle>::span_bug::<rustc_span[267b34eb586afd37]::span_encoding::Span, alloc[98b3c20953f4fbe5]::string::String>
  13:     0x73bca06e86e7 - rustc_middle[2b65deb07cad4442]::util::bug::opt_span_bug_fmt::<rustc_span[267b34eb586afd37]::span_encoding::Span>::{closure#0}
  14:     0x73bca06d0c0a - rustc_middle[2b65deb07cad4442]::ty::context::tls::with_opt::<rustc_middle[2b65deb07cad4442]::util::bug::opt_span_bug_fmt<rustc_span[267b34eb586afd37]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  15:     0x73bca06d0a9b - rustc_middle[2b65deb07cad4442]::ty::context::tls::with_context_opt::<rustc_middle[2b65deb07cad4442]::ty::context::tls::with_opt<rustc_middle[2b65deb07cad4442]::util::bug::opt_span_bug_fmt<rustc_span[267b34eb586afd37]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  16:     0x73bc9f0446a7 - rustc_middle[2b65deb07cad4442]::util::bug::span_bug_fmt::<rustc_span[267b34eb586afd37]::span_encoding::Span>
  17:     0x73bca2a8bc20 - rustc_const_eval[c1d2b202d9973a02]::const_eval::eval_queries::eval_body_using_ecx::<rustc_middle[2b65deb07cad4442]::mir::interpret::allocation::ConstAllocation>
  18:     0x73bca29f2e3d - rustc_const_eval[c1d2b202d9973a02]::const_eval::eval_queries::eval_static_initializer_provider
  19:     0x73bca29f2be7 - rustc_query_impl[31526c927efa8eec]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[31526c927efa8eec]::query_impl::eval_static_initializer::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2b65deb07cad4442]::query::erase::Erased<[u8; 16usize]>>
  20:     0x73bca29f2bc9 - <rustc_query_impl[31526c927efa8eec]::query_impl::eval_static_initializer::dynamic_query::{closure#2} as core[ce4f568dace374e]::ops::function::FnOnce<(rustc_middle[2b65deb07cad4442]::ty::context::TyCtxt, rustc_span[267b34eb586afd37]::def_id::DefId)>>::call_once
  21:     0x73bca180e6da - rustc_query_system[8b7296974754ceb3]::query::plumbing::try_execute_query::<rustc_query_impl[31526c927efa8eec]::DynamicConfig<rustc_query_system[8b7296974754ceb3]::query::caches::DefIdCache<rustc_middle[2b65deb07cad4442]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[31526c927efa8eec]::plumbing::QueryCtxt, false>
  22:     0x73bca26252b8 - rustc_query_impl[31526c927efa8eec]::query_impl::eval_static_initializer::get_query_non_incr::__rust_end_short_backtrace
  23:     0x73bca1a3a249 - <rustc_middle[2b65deb07cad4442]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[4e6fa7c2cad24599]::check_crate::{closure#3}>::{closure#0}
  24:     0x73bca1a37b37 - rustc_hir_analysis[4e6fa7c2cad24599]::check_crate
  25:     0x73bca1a42584 - rustc_interface[51c1904b6ef58290]::passes::run_required_analyses
  26:     0x73bca25d88de - rustc_interface[51c1904b6ef58290]::passes::analysis
  27:     0x73bca25d88af - rustc_query_impl[31526c927efa8eec]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[31526c927efa8eec]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2b65deb07cad4442]::query::erase::Erased<[u8; 1usize]>>
  28:     0x73bca25af7ba - rustc_query_system[8b7296974754ceb3]::query::plumbing::try_execute_query::<rustc_query_impl[31526c927efa8eec]::DynamicConfig<rustc_query_system[8b7296974754ceb3]::query::caches::SingleCache<rustc_middle[2b65deb07cad4442]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[31526c927efa8eec]::plumbing::QueryCtxt, false>
  29:     0x73bca25af48e - rustc_query_impl[31526c927efa8eec]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  30:     0x73bca26503eb - rustc_interface[51c1904b6ef58290]::interface::run_compiler::<core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>, rustc_driver_impl[45224e78b6d2fe59]::run_compiler::{closure#0}>::{closure#1}
  31:     0x73bca2541ca1 - std[85c61899f894cf29]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[51c1904b6ef58290]::util::run_in_thread_with_globals<rustc_interface[51c1904b6ef58290]::util::run_in_thread_pool_with_globals<rustc_interface[51c1904b6ef58290]::interface::run_compiler<core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>, rustc_driver_impl[45224e78b6d2fe59]::run_compiler::{closure#0}>::{closure#1}, core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>>::{closure#0}, core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>>
  32:     0x73bca2541948 - <<std[85c61899f894cf29]::thread::Builder>::spawn_unchecked_<rustc_interface[51c1904b6ef58290]::util::run_in_thread_with_globals<rustc_interface[51c1904b6ef58290]::util::run_in_thread_pool_with_globals<rustc_interface[51c1904b6ef58290]::interface::run_compiler<core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>, rustc_driver_impl[45224e78b6d2fe59]::run_compiler::{closure#0}>::{closure#1}, core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>>::{closure#0}, core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[ce4f568dace374e]::result::Result<(), rustc_span[267b34eb586afd37]::ErrorGuaranteed>>::{closure#1} as core[ce4f568dace374e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  33:     0x73bca254107b - std::sys::pal::unix::thread::Thread::new::thread_start::h6f16c939ae6ab66d
  34:     0x73bc9c8a339d - <unknown>
  35:     0x73bc9c92849c - <unknown>
  36:                0x0 - <unknown>

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: please make sure that you have updated to the latest nightly

note: rustc 1.85.0-nightly (acf48426b 2024-12-06) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [eval_static_initializer] evaluating initializer of static `C`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors; 1 warning emitted

Some errors have detailed explanations: E0308, E0310, E0601.
For more information about an error, try `rustc --explain E0308`.

[matthiaskrgr]

this bisects to #133704 cc @RalfJung

[RalfJung]

Ah, you fix one ICE, you introduce another...

[RalfJung]

Further minimized:

struct B<T: ?Sized + Send + 'static> {
    x: &'static T,
}
static STR: &'static [u8] = "a b";
static C: &B<[u8]> = &B { x: STR };