ICE: None, compiler/rustc_const_eval/src/interpret/validity.rs

[matthiaskrgr]

auto-reduced (treereduce-rust):

#![feature(const_mut_refs)]
#![feature(const_refs_to_static)]

use std::cell::UnsafeCell;

struct Meh {
    x: &'static UnsafeCell<i32>,
}

const MUH: Meh = Meh {
    x: &mut *(&READONLY as *const _ as *mut _),
};

static READONLY: i32 = 0;

pub fn main() {}

original code

original:

//@ compile-flags: -Zunleash-the-miri-inside-of-you
//@ normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
//@ normalize-stderr-test "([0-9a-f][0-9a-f] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> "HEX_DUMP"
#![allow(invalid_reference_casting, static_mut_refs)]
#![deny(const_eval_mutable_ptr_in_final_value)]
use std::cell::UnsafeCell;
use std::sync::POINTS_TO_MUTABLE2::*;

// this test ensures that our mutability story is sound

struct Meh {
    x: &'static UnsafeCell<i32>,
}
unsafe impl Sync for Synced {}

//~^ ERROR: it is undefined behavior to use this value
// all allocs interned here will be marked immutable.
const MUH: Meh = Meh {
    //~^ ERROR encountered mutable pointer in final value of constant
    //~| WARNING this was previously accepted by the compiler
    //~| ERROR: it is undefined behavior to use this value
    x: &mut *(&READONLY as *const _ as *mut _),
};

struct Synced {
    x: UnsafeCell<i32>,
}
unsafe impl Sync for Synced {}

// Make sure we also catch this behind a type-erased `dyn Trait` reference.
const SNEAKY: &dyn Sync = &Synced { x: UnsafeCell::new(42) };
//~^ ERROR: mutable pointer in final value
//~| WARNING this was previously accepted by the compiler
//~| ERROR it is undefined behavior to use this value

// Make sure we also catch mutable references in values that shouldn't have them.
static mut FOO: i32 = 0;
const SUBTLE: &mut i32 = unsafe { &mut FOO };
//~^ ERROR: it is undefined behavior to use this value
//~| static

const BLUNT: &mut i32 = &mut 42;
//~^ ERROR: mutable pointer in final value
//~| WARNING this was previously accepted by the compiler
//~| ERROR it is undefined behavior to use this value

// Check for mutable references to read-only memory.
static READONLY: i32 = 0;
static mut MUT_TO_READONLY: &mut i32 = unsafe { &mut *(&READONLY as *const _ as *mut _) };
//~^ ERROR: it is undefined behavior to use this value
//~| pointing to read-only memory

// Check for consts pointing to mutable memory.
// These are fine as long as they are not being read.
static mut MUTABLE: i32 = 42;
const POINTS_TO_MUTABLE1: &i32 = unsafe { &MUTABLE }; //~ERROR: undefined behavior
//~| encountered reference to mutable memory
const READS_FROM_MUTABLE: i32 = *POINTS_TO_MUTABLE1;
static mut MUTABLE_REF: &mut i32 = &mut 42;
const POINTS_TO_MUTABLE2: &i32 = unsafe { &*MUTABLE_REF };
//~^ ERROR: evaluation of constant value failed
//~| accesses mutable global memory

const POINTS_TO_MUTABLE_INNER: *const i32 = &mut 42 as *mut _ as *const _;
//~^ ERROR: it is undefined behavior to use this value
//~| WARNING this was previously accepted by the compiler

const POINTS_TO_MUTABLE_INNER2: *const i32 = &mut 42 as *const _;
//~^ ERROR: mutable pointer in final value
//~| WARNING this was previously accepted by the compiler

const INTERIOR_MUTABLE_BEHIND_RAW: *mut i32 = &UnsafeCell::new(42) as *const _ as *mut _;
//~^ ERROR: mutable pointer in final value
//~| WARNING this was previously accepted by the compiler

struct SyncPtr<T> {
    x: *const T,
}
unsafe impl<T> Sync for SyncPtr<T> {}

// These pass the lifetime checks because of the "tail expression" / "outer scope" rule.
// (This relies on `SyncPtr` being a curly brace struct.)
// However, we intern the inner memory as read-only, so this must be rejected.
// (Also see `static-no-inner-mut` for similar tests on `static`.)
const SUBTLE: &mut i32 = unsafe { &mut FOO };
//~^ ERROR mutable pointer in final value
//~| WARNING this was previously accepted by the compiler

const RAW_MUT_CAST: SyncPtr<i32> = SyncPtr { x: &mut 42 as *mut _ as *const _ };
//~^ ERROR mutable pointer in final value
//~| WARNING this was previously accepted by the compiler

const RAW_MUT_COERCE: SyncPtr<i32> = SyncPtr { x: &mut 0 };
//~^ ERROR mutable pointer in final value
//~| WARNING this was previously accepted by the compiler

fn main() {
    unsafe {
        *MUH.x.get() = 99;
    }
}

Version information

rustc 1.78.0-nightly (d7723b219 2024-03-15)
binary: rustc
commit-hash: d7723b21910075a3c38c2b6e64b2467394c93724
commit-date: 2024-03-15
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcrate-attr=feature(const_mut_refs) -Zcrate-attr=feature(const_refs_to_static)

Program output

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.3yun4V90lzTt/rustc_testrunner_tmpdir_reporting.rjeSi3TM1Rid/mvce.rs:11:26
   |
11 | static READONLY: i32 = 0;
   |                          ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.3yun4V90lzTt/rustc_testrunner_tmpdir_reporting.rjeSi3TM1Rid/mvce.rs`

thread 'rustc' panicked at compiler/rustc_const_eval/src/interpret/validity.rs:712:65:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0:     0x7f39096dc912 - std::backtrace_rs::backtrace::libunwind::trace::h2da6c6ec1776ed1b
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7f39096dc912 - std::backtrace_rs::backtrace::trace_unsynchronized::h0cb696e9cf0107ba
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f39096dc912 - std::sys_common::backtrace::_print_fmt::hfb11ed7a7d38a028
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f39096dc912 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h1048d052a888b26c
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f390972dc8c - core::fmt::rt::Argument::fmt::hcf8265a03a389e34
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/core/src/fmt/rt.rs:142:9
   5:     0x7f390972dc8c - core::fmt::write::hd12c3a84e62e1cec
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/core/src/fmt/mod.rs:1153:17
   6:     0x7f39096d180f - std::io::Write::write_fmt::h236993be0d5d91de
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/io/mod.rs:1843:15
   7:     0x7f39096dc6e4 - std::sys_common::backtrace::_print::he44e9b7b149d34c3
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f39096dc6e4 - std::sys_common::backtrace::print::h6f8e8e3b9f052551
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f39096df3eb - std::panicking::default_hook::{{closure}}::h321d04c9179dccca
  10:     0x7f39096df143 - std::panicking::default_hook::hd949d1362c2e5565
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/panicking.rs:292:9
  11:     0x7f39063a68ef - std[8d86c5c35c0bd7fb]::panicking::update_hook::<alloc[b74d3dbad420fbd6]::boxed::Box<rustc_driver_impl[724f095572d73222]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f39096dfb50 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h4f6c988be7bdee68
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/alloc/src/boxed.rs:2034:9
  13:     0x7f39096dfb50 - std::panicking::rust_panic_with_hook::hb71de646be3b3469
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/panicking.rs:783:13
  14:     0x7f39096df859 - std::panicking::begin_panic_handler::{{closure}}::hbca15a8a0a3dee72
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/panicking.rs:649:13
  15:     0x7f39096dcde6 - std::sys_common::backtrace::__rust_end_short_backtrace::h885125d06f4d13f0
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7f39096df5c4 - rust_begin_unwind
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/panicking.rs:645:5
  17:     0x7f390972a1a5 - core::panicking::panic_fmt::ha3facef8c988a935
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/core/src/panicking.rs:72:14
  18:     0x7f390972a263 - core::panicking::panic::h0108ad4bd7f0026d
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/core/src/panicking.rs:145:5
  19:     0x7f3909729f36 - core::option::unwrap_failed::h1e7018e297d5a5da
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/core/src/option.rs:1985:5
  20:     0x7f3908d63259 - <rustc_const_eval[1fc5f74b41ebce23]::interpret::validity::ValidityVisitor<rustc_const_eval[1fc5f74b41ebce23]::const_eval::machine::CompileTimeInterpreter>>::in_mutable_memory.cold.0
  21:     0x7f39076e03ca - <rustc_const_eval[1fc5f74b41ebce23]::interpret::validity::ValidityVisitor<rustc_const_eval[1fc5f74b41ebce23]::const_eval::machine::CompileTimeInterpreter> as rustc_const_eval[1fc5f74b41ebce23]::interpret::visitor::ValueVisitor<rustc_const_eval[1fc5f74b41ebce23]::const_eval::machine::CompileTimeInterpreter>>::visit_value
  22:     0x7f3907c1a30f - rustc_const_eval[1fc5f74b41ebce23]::const_eval::eval_queries::eval_to_allocation_raw_provider
  23:     0x7f3907c18cf6 - rustc_query_impl[5406894609d381a6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5406894609d381a6]::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[35d2191f4cbfc53b]::query::erase::Erased<[u8; 24usize]>>
  24:     0x7f3907deb351 - rustc_query_system[40cbee46219fc421]::query::plumbing::try_execute_query::<rustc_query_impl[5406894609d381a6]::DynamicConfig<rustc_query_system[40cbee46219fc421]::query::caches::DefaultCache<rustc_middle[35d2191f4cbfc53b]::ty::ParamEnvAnd<rustc_middle[35d2191f4cbfc53b]::mir::interpret::GlobalId>, rustc_middle[35d2191f4cbfc53b]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[5406894609d381a6]::plumbing::QueryCtxt, false>
  25:     0x7f3907deaf2c - rustc_query_impl[5406894609d381a6]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  26:     0x7f3907dec710 - rustc_const_eval[1fc5f74b41ebce23]::const_eval::eval_queries::eval_to_const_value_raw_provider
  27:     0x7f3907dec536 - rustc_query_impl[5406894609d381a6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5406894609d381a6]::query_impl::eval_to_const_value_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[35d2191f4cbfc53b]::query::erase::Erased<[u8; 24usize]>>
  28:     0x7f3907deb314 - rustc_query_system[40cbee46219fc421]::query::plumbing::try_execute_query::<rustc_query_impl[5406894609d381a6]::DynamicConfig<rustc_query_system[40cbee46219fc421]::query::caches::DefaultCache<rustc_middle[35d2191f4cbfc53b]::ty::ParamEnvAnd<rustc_middle[35d2191f4cbfc53b]::mir::interpret::GlobalId>, rustc_middle[35d2191f4cbfc53b]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[5406894609d381a6]::plumbing::QueryCtxt, false>
  29:     0x7f3907deae2c - rustc_query_impl[5406894609d381a6]::query_impl::eval_to_const_value_raw::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7f3907bb5b8b - <rustc_middle[35d2191f4cbfc53b]::query::plumbing::TyCtxtEnsure>::const_eval_poly
  31:     0x7f3907bb3d91 - rustc_hir_analysis[c56ac84798d79461]::check_crate
  32:     0x7f3907d987ea - rustc_interface[62605c20d0dc0fef]::passes::analysis
  33:     0x7f3907d98425 - rustc_query_impl[5406894609d381a6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5406894609d381a6]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[35d2191f4cbfc53b]::query::erase::Erased<[u8; 1usize]>>
  34:     0x7f3908406165 - rustc_query_system[40cbee46219fc421]::query::plumbing::try_execute_query::<rustc_query_impl[5406894609d381a6]::DynamicConfig<rustc_query_system[40cbee46219fc421]::query::caches::SingleCache<rustc_middle[35d2191f4cbfc53b]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[5406894609d381a6]::plumbing::QueryCtxt, false>
  35:     0x7f3908405ec9 - rustc_query_impl[5406894609d381a6]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  36:     0x7f390815e284 - rustc_interface[62605c20d0dc0fef]::interface::run_compiler::<core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>, rustc_driver_impl[724f095572d73222]::run_compiler::{closure#0}>::{closure#0}
  37:     0x7f3908623805 - std[8d86c5c35c0bd7fb]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[62605c20d0dc0fef]::util::run_in_thread_with_globals<rustc_interface[62605c20d0dc0fef]::util::run_in_thread_pool_with_globals<rustc_interface[62605c20d0dc0fef]::interface::run_compiler<core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>, rustc_driver_impl[724f095572d73222]::run_compiler::{closure#0}>::{closure#0}, core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>>::{closure#0}, core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>>
  38:     0x7f3908623632 - <<std[8d86c5c35c0bd7fb]::thread::Builder>::spawn_unchecked_<rustc_interface[62605c20d0dc0fef]::util::run_in_thread_with_globals<rustc_interface[62605c20d0dc0fef]::util::run_in_thread_pool_with_globals<rustc_interface[62605c20d0dc0fef]::interface::run_compiler<core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>, rustc_driver_impl[724f095572d73222]::run_compiler::{closure#0}>::{closure#0}, core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>>::{closure#0}, core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d25ee0c10dd6dc91]::result::Result<(), rustc_span[6c3fee00dc2a924e]::ErrorGuaranteed>>::{closure#1} as core[d25ee0c10dd6dc91]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  39:     0x7f39096e91e5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hab5d072bb143d8fe
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/alloc/src/boxed.rs:2020:9
  40:     0x7f39096e91e5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he1f566ad483a8fda
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/alloc/src/boxed.rs:2020:9
  41:     0x7f39096e91e5 - std::sys::pal::unix::thread::Thread::new::thread_start::h23d47a8da771b95c
                               at /rustc/d7723b21910075a3c38c2b6e64b2467394c93724/library/std/src/sys/pal/unix/thread.rs:108:17
  42:     0x7f390326455a - <unknown>
  43:     0x7f39032e1a3c - <unknown>
  44:                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 (d7723b219 2024-03-15) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z crate-attr=feature(const_mut_refs) -Z crate-attr=feature(const_refs_to_static) -Z dump-mir-dir=dir

query stack during panic:
#0 [eval_to_allocation_raw] const-evaluating + checking `MUH`
#1 [eval_to_const_value_raw] simplifying constant for the type system `MUH`
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0601`.

[matthiaskrgr]

ICE since #121087 cc @oli-obk