ICE: expected memory, got Static(DefId(0:6 ... ice-zst-static-access.rs with --emir mir

[matthiaskrgr]

Command: rustc src/test/ui/consts/ice-zst-static-access.rs --emit mir

Code

This code is from src/test/ui/consts/ice-zst-static-access.rs

// check-pass

// This is a regression test for ICEs from
// https://github.com/rust-lang/rust/issues/71612
// and
// https://github.com/rust-lang/rust/issues/71709

#[derive(Copy, Clone)]
pub struct Glfw;

static mut GLFW: Option<Glfw> = None;
pub fn new() -> Glfw {
    unsafe {
        if let Some(glfw) = GLFW {
            return glfw;
        } else {
            todo!()
        }
    };
}

extern "C" {
    static _dispatch_queue_attr_concurrent: [u8; 0];
}

static DISPATCH_QUEUE_CONCURRENT: &'static [u8; 0] =
    unsafe { &_dispatch_queue_attr_concurrent };

fn main() {
    *DISPATCH_QUEUE_CONCURRENT;
    new();
}

Meta

rustc --version --verbose:
The compiler is at revision aeb4738

rustc 1.45.0-dev
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-unknown-linux-gnu
release: 1.45.0-dev
LLVM version: 9.0

Error output

warning: unused unary operation that must be used
  --> ./ui/consts/ice-zst-static-access.rs:30:5
   |
30 |     *DISPATCH_QUEUE_CONCURRENT;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(unused_must_use)]` on by default

error: internal compiler error: src/librustc_middle/mir/interpret/mod.rs:389: expected memory, got Static(DefId(0:6 ~ ice_zst_static_access[317d]::[0]::_dispatch_queue_attr_concurrent[0]))

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:907:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.45.0-dev running on x86_64-unknown-linux-gnu

error: aborting due to previous error; 1 warning emitted

Backtrace

warning: unused unary operation that must be used
  --> ./ui/consts/ice-zst-static-access.rs:30:5
   |
30 |     *DISPATCH_QUEUE_CONCURRENT;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(unused_must_use)]` on by default

error: internal compiler error: src/librustc_middle/mir/interpret/mod.rs:389: expected memory, got Static(DefId(0:6 ~ ice_zst_static_access[317d]::[0]::_dispatch_queue_attr_concurrent[0]))

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:907:9
stack backtrace:
   0:     0x7fee57224089 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hd08e85f94cff0dfc
   1:     0x7fee5726eadc - core::fmt::write::h65255e7874586eb2
   2:     0x7fee572115a0 - std::io::Write::write_fmt::h3426e27a15389754
   3:     0x7fee571feb25 - std::panicking::default_hook::{{closure}}::hf30497d1f1ca597f
   4:     0x7fee571fe80f - std::panicking::default_hook::h9e9a0711680f7c71
   5:     0x7fee589fcd83 - rustc_driver::report_ice::h5ae862a314f73c0a
   6:     0x7fee571ff21d - std::panicking::rust_panic_with_hook::hf9e06a37c137122b
   7:     0x7fee5ca83563 - std::panicking::begin_panic::h33636113330b48aa
   8:     0x7fee5cabda80 - rustc_errors::HandlerInner::bug::h52d7e1cb0240ea9a
   9:     0x7fee5cabc310 - rustc_errors::Handler::bug::hb9179f645d9eebfc
  10:     0x7fee5c5c99bd - rustc_middle::util::bug::opt_span_bug_fmt::{{closure}}::ha2320eff725974f0
  11:     0x7fee5c5ba015 - rustc_middle::ty::context::tls::with_opt::{{closure}}::ha5fdac267ed6d665
  12:     0x7fee5c5b9f7e - rustc_middle::ty::context::tls::with_opt::h5a46bd0f8944e3da
  13:     0x7fee5c5c98c5 - rustc_middle::util::bug::opt_span_bug_fmt::hca9e39ad66e1e817
  14:     0x7fee5c5c9830 - rustc_middle::util::bug::bug_fmt::h12c26b5ba6d149ef
  15:     0x7fee5c2fb158 - rustc_middle::ty::print::pretty::PrettyPrinter::pretty_print_const::h817e42958e0f08aa
  16:     0x7fee5c3eff8c - rustc_middle::mir::pretty_print_const::h3e9268740a5abca3
  17:     0x7fee5726eadc - core::fmt::write::h65255e7874586eb2
  18:     0x7fee5726ff72 - <core::fmt::Formatter as core::fmt::Write>::write_fmt::h4391506298bd83e2
  19:     0x7fee5c717774 - <&T as core::fmt::Debug>::fmt::h57a5131d265df8f0
  20:     0x7fee5726eadc - core::fmt::write::h65255e7874586eb2
  21:     0x7fee5726ff72 - <core::fmt::Formatter as core::fmt::Write>::write_fmt::h4391506298bd83e2
  22:     0x7fee5c3ed5c8 - <rustc_middle::mir::Operand as core::fmt::Debug>::fmt::hb676f8b47d6c04be
  23:     0x7fee5726eadc - core::fmt::write::h65255e7874586eb2
  24:     0x7fee5726ff72 - <core::fmt::Formatter as core::fmt::Write>::write_fmt::h4391506298bd83e2
  25:     0x7fee5c3edc2b - <rustc_middle::mir::Rvalue as core::fmt::Debug>::fmt::h08da1cab9d3f68fd
  26:     0x7fee5726eadc - core::fmt::write::h65255e7874586eb2
  27:     0x7fee5726ff72 - <core::fmt::Formatter as core::fmt::Write>::write_fmt::h4391506298bd83e2
  28:     0x7fee5c3ecf37 - <rustc_middle::mir::Statement as core::fmt::Debug>::fmt::h36848a833a8ff140
  29:     0x7fee5726ea4c - core::fmt::write::h65255e7874586eb2
  30:     0x7fee5724d903 - alloc::fmt::format::h133900b0fc9df957
  31:     0x7fee5b2d700a - rustc_mir::util::pretty::write_mir_pretty::hb3aac4600eda79f5
  32:     0x7fee5b5317d1 - rustc_mir::transform::dump_mir::emit_mir::h1bd5e01ce1a125e0
  33:     0x7fee58dadff3 - rustc_interface::passes::start_codegen::h57d97e26628aab71
  34:     0x7fee58c976f0 - rustc_middle::ty::context::tls::enter_global::h5b0209aac3b02988
  35:     0x7fee58cb1ac6 - rustc_interface::queries::Queries::ongoing_codegen::h6cad2d99c2dcd590
  36:     0x7fee589ca1b1 - rustc_interface::interface::run_compiler_in_existing_thread_pool::h9998dbf493c360fb
  37:     0x7fee58a0a08e - scoped_tls::ScopedKey<T>::set::h429ea38eed219381
  38:     0x7fee58a03494 - rustc_ast::attr::with_globals::h520bb7fad596003b
  39:     0x7fee58a1214f - std::sys_common::backtrace::__rust_begin_short_backtrace::h66a2db9ac00d8f49
  40:     0x7fee58b58a5e - core::ops::function::FnOnce::call_once{{vtable.shim}}::hed3e3cb32357dea8
  41:     0x7fee571ffb38 - std::sys::unix::thread::Thread::new::thread_start::h294f0533d573419f
  42:     0x7fee56f2d46f - start_thread
  43:     0x7fee5704a3d3 - clone
  44:                0x0 - <unknown>

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.45.0-dev running on x86_64-unknown-linux-gnu

query stack during panic:
end of query stack
error: aborting due to previous error; 1 warning emitted

[RalfJung]

This happens on stable, too.

Cc @rust-lang/wg-const-eval

[matthiaskrgr]

This happens on stable, too.

Not very surprising imo since the original corresponding tickets ( #71612 , #71709 ) are only ~2 weeks old.

[RalfJung]

Those tickets report different ICEs, from what I can see. Same source code, but different assertion hit in the compiler.

[matthiaskrgr]

Reduced:

extern "C" {
    static _dispatch_queue_attr_concurrent: [u8; 0];
}

fn main() {
let x: &[u8; 0] =
    unsafe { &_dispatch_queue_attr_concurrent };
}

when I use an underscore binding _ instead of x, the ICE no longer occurs:

extern "C" {
    static _dispatch_queue_attr_concurrent: [u8; 0];
}

fn main() {
let _: &[u8; 0] =
    unsafe { &_dispatch_queue_attr_concurrent };
}

[matthiaskrgr]

The same ICE also triggers on this file in the miri submodule: ./src/tools/miri/tests/compile-fail/stacked_borrows/unescaped_static.rs (with --emit mir)

static ARRAY: [u8; 2] = [0, 1];

fn main() {
    let ptr_to_first = &ARRAY[0] as *const u8;
    // Illegally use this to access the 2nd element.
    let _val = unsafe { *ptr_to_first.add(1) }; //~ ERROR borrow stack
}

[oli-obk]

I'm guessing it's

rust/src/librustc_middle/ty/print/pretty.rs

Line 962 in 09c817e

.unwrap_memory()

so we need to match on the result of the global_alloc and print different output depending on it