ICE when using offset_of with an unsized type

[tmiasko]

Code

#![feature(offset_of)]
use std::fmt::Debug;
struct S<T: ?Sized> {
    a: u64,
    b: T,
}
fn main() {
    let x = core::mem::offset_of!(S<Box<()>>, a);
    let y = core::mem::offset_of!(S<dyn Debug>, a);
}

Meta

rustc --version --verbose:

rustc 1.71.0-nightly (cca7ee581 2023-05-27)
binary: rustc
commit-hash: cca7ee58110726983951a19d5fb7316d9243925d
commit-date: 2023-05-27
host: x86_64-unknown-linux-gnu
release: 1.71.0-nightly
LLVM version: 16.0.4

Error output

thread 'rustc' panicked at 'assertion failed: bx.cx().type_is_sized(ty)', /rustc/cca7ee58110726983951a19d5fb7316d9243925d/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:671:17

Backtrace

thread 'rustc' panicked at 'assertion failed: bx.cx().type_is_sized(ty)', /rustc/cca7ee58110726983951a19d5fb7316d9243925d/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:671:17
stack backtrace:
   0:     0x7f61ea3698b1 - std::backtrace_rs::backtrace::libunwind::trace::h91704ec918f77c78
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f61ea3698b1 - std::backtrace_rs::backtrace::trace_unsynchronized::hd25690acb7e38be5
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f61ea3698b1 - std::sys_common::backtrace::_print_fmt::h146bb9a645668a5c
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f61ea3698b1 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h06516363e7e12320
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f61ea3ca2ff - core::fmt::rt::Argument::fmt::h4d33ba7fbbbaa80b
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/core/src/fmt/rt.rs:138:9
   5:     0x7f61ea3ca2ff - core::fmt::write::h0c2495f04f0fd4f1
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/core/src/fmt/mod.rs:1094:21
   6:     0x7f61ea35cab1 - std::io::Write::write_fmt::hb47ded088c57ebd2
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/io/mod.rs:1713:15
   7:     0x7f61ea3696c5 - std::sys_common::backtrace::_print::hbc8e99e0f4dc2dd4
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f61ea3696c5 - std::sys_common::backtrace::print::hf14b108899d6a9c5
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f61ea36c387 - std::panicking::default_hook::{{closure}}::hc1a53ebba49377ca
  10:     0x7f61ea36c174 - std::panicking::default_hook::ha7e07ec692015fe7
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/panicking.rs:288:9
  11:     0x7f61ed512efb - <rustc_driver_impl[9b9fd057b079c87d]::install_ice_hook::{closure#0} as core[dc0e626abd4c9e52]::ops::function::FnOnce<(&core[dc0e626abd4c9e52]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  12:     0x7f61ea36cacd - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h8242157725b18837
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/alloc/src/boxed.rs:1999:9
  13:     0x7f61ea36cacd - std::panicking::rust_panic_with_hook::h8c3d4fc60d33a402
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/panicking.rs:709:13
  14:     0x7f61ea36c821 - std::panicking::begin_panic_handler::{{closure}}::h9541d40caad03645
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/panicking.rs:595:13
  15:     0x7f61ea369ce6 - std::sys_common::backtrace::__rust_end_short_backtrace::h26bacb47f2917c74
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/sys_common/backtrace.rs:151:18
  16:     0x7f61ea36c5b2 - rust_begin_unwind
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/panicking.rs:593:5
  17:     0x7f61ea3c6583 - core::panicking::panic_fmt::h1d3026b296abc2d0
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/core/src/panicking.rs:67:14
  18:     0x7f61ea3c6613 - core::panicking::panic::hcf0146841de65acb
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/core/src/panicking.rs:117:5
  19:     0x7f61ebe6499b - <rustc_codegen_ssa[846eb25a9e917dd8]::mir::FunctionCx<rustc_codegen_llvm[8113e9edcdd0c14]::builder::Builder>>::codegen_rvalue_operand
  20:     0x7f61ebe35992 - rustc_codegen_ssa[846eb25a9e917dd8]::mir::codegen_mir::<rustc_codegen_llvm[8113e9edcdd0c14]::builder::Builder>
  21:     0x7f61ecb51c2b - rustc_codegen_llvm[8113e9edcdd0c14]::base::compile_codegen_unit::module_codegen
  22:     0x7f61ecb4f149 - <rustc_codegen_llvm[8113e9edcdd0c14]::LlvmCodegenBackend as rustc_codegen_ssa[846eb25a9e917dd8]::traits::backend::ExtraBackendMethods>::compile_codegen_unit
  23:     0x7f61ecb4caf7 - rustc_codegen_ssa[846eb25a9e917dd8]::base::codegen_crate::<rustc_codegen_llvm[8113e9edcdd0c14]::LlvmCodegenBackend>
  24:     0x7f61ecb4c3fb - <rustc_codegen_llvm[8113e9edcdd0c14]::LlvmCodegenBackend as rustc_codegen_ssa[846eb25a9e917dd8]::traits::backend::CodegenBackend>::codegen_crate
  25:     0x7f61ec79c402 - <rustc_session[7699662e81a4adee]::session::Session>::time::<alloc[cb0f54882c31da79]::boxed::Box<dyn core[dc0e626abd4c9e52]::any::Any>, rustc_interface[31484fcbe0571e9c]::passes::start_codegen::{closure#0}>
  26:     0x7f61ec79bf4b - rustc_interface[31484fcbe0571e9c]::passes::start_codegen
  27:     0x7f61ec79a05d - <rustc_middle[6a6e7583393ba8b2]::ty::context::GlobalCtxt>::enter::<<rustc_interface[31484fcbe0571e9c]::queries::Queries>::ongoing_codegen::{closure#0}::{closure#0}, core[dc0e626abd4c9e52]::result::Result<alloc[cb0f54882c31da79]::boxed::Box<dyn core[dc0e626abd4c9e52]::any::Any>, rustc_span[95ab60cea81a8973]::ErrorGuaranteed>>
  28:     0x7f61ec79808d - <rustc_interface[31484fcbe0571e9c]::queries::Queries>::ongoing_codegen
  29:     0x7f61ec7976a9 - <rustc_interface[31484fcbe0571e9c]::interface::Compiler>::enter::<rustc_driver_impl[9b9fd057b079c87d]::run_compiler::{closure#1}::{closure#2}, core[dc0e626abd4c9e52]::result::Result<core[dc0e626abd4c9e52]::option::Option<rustc_interface[31484fcbe0571e9c]::queries::Linker>, rustc_span[95ab60cea81a8973]::ErrorGuaranteed>>
  30:     0x7f61ec794e73 - std[9595413e0839bf8b]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[31484fcbe0571e9c]::util::run_in_thread_pool_with_globals<rustc_interface[31484fcbe0571e9c]::interface::run_compiler<core[dc0e626abd4c9e52]::result::Result<(), rustc_span[95ab60cea81a8973]::ErrorGuaranteed>, rustc_driver_impl[9b9fd057b079c87d]::run_compiler::{closure#1}>::{closure#0}, core[dc0e626abd4c9e52]::result::Result<(), rustc_span[95ab60cea81a8973]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[dc0e626abd4c9e52]::result::Result<(), rustc_span[95ab60cea81a8973]::ErrorGuaranteed>>
  31:     0x7f61ecdbc655 - <<std[9595413e0839bf8b]::thread::Builder>::spawn_unchecked_<rustc_interface[31484fcbe0571e9c]::util::run_in_thread_pool_with_globals<rustc_interface[31484fcbe0571e9c]::interface::run_compiler<core[dc0e626abd4c9e52]::result::Result<(), rustc_span[95ab60cea81a8973]::ErrorGuaranteed>, rustc_driver_impl[9b9fd057b079c87d]::run_compiler::{closure#1}>::{closure#0}, core[dc0e626abd4c9e52]::result::Result<(), rustc_span[95ab60cea81a8973]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[dc0e626abd4c9e52]::result::Result<(), rustc_span[95ab60cea81a8973]::ErrorGuaranteed>>::{closure#1} as core[dc0e626abd4c9e52]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  32:     0x7f61ea376ff5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8594d8e8eb390362
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/alloc/src/boxed.rs:1985:9
  33:     0x7f61ea376ff5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hc4f2baff9e44ab11
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/alloc/src/boxed.rs:1985:9
  34:     0x7f61ea376ff5 - std::sys::unix::thread::Thread::new::thread_start::hdf2074fec680ece7
                               at /rustc/cca7ee58110726983951a19d5fb7316d9243925d/library/std/src/sys/unix/thread.rs:108:17
  35:     0x7f61ea11bfd4 - start_thread
                               at ./nptl/pthread_create.c:442:8
  36:     0x7f61ea19c5bc - __GI___clone3
                               at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
  37:                0x0 - <unknown>