regression: "cycle detected when borrow-checking" in `offset_of!`

[cuviper]

[INFO] [stdout] error[E0391]: cycle detected when borrow-checking `firmware::operation::implement::stm::gain::tests::test_phase_half`
[INFO] [stdout]    --> src/firmware/operation/implement/stm/gain.rs:649:5
[INFO] [stdout]     |
[INFO] [stdout] 649 |     fn test_phase_half() {
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout] note: ...which requires promoting constants in MIR for `firmware::operation::implement::stm::gain::tests::test_phase_half`...
[INFO] [stdout]    --> src/firmware/operation/implement/stm/gain.rs:649:5
[INFO] [stdout]     |
[INFO] [stdout] 649 |     fn test_phase_half() {
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] note: ...which requires simplifying constant for the type system `firmware::operation::implement::stm::gain::tests::test_phase_half::{constant#0}`...
[INFO] [stdout]    --> src/firmware/operation/implement/stm/gain.rs:704:20
[INFO] [stdout]     |
[INFO] [stdout] 704 |                 tx[offset_of!(GainSTMHead, flag)] & 0x3F
[INFO] [stdout]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] note: ...which requires const-evaluating + checking `firmware::operation::implement::stm::gain::tests::test_phase_half::{constant#0}`...
[INFO] [stdout]    --> src/firmware/operation/implement/stm/gain.rs:704:20
[INFO] [stdout]     |
[INFO] [stdout] 704 |                 tx[offset_of!(GainSTMHead, flag)] & 0x3F
[INFO] [stdout]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] note: ...which requires caching mir of `firmware::operation::implement::stm::gain::tests::test_phase_half::{constant#0}` for CTFE...
[INFO] [stdout]    --> src/firmware/operation/implement/stm/gain.rs:704:20
[INFO] [stdout]     |
[INFO] [stdout] 704 |                 tx[offset_of!(GainSTMHead, flag)] & 0x3F
[INFO] [stdout]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] note: ...which requires elaborating drops for `firmware::operation::implement::stm::gain::tests::test_phase_half::{constant#0}`...
[INFO] [stdout]    --> src/firmware/operation/implement/stm/gain.rs:704:20
[INFO] [stdout]     |
[INFO] [stdout] 704 |                 tx[offset_of!(GainSTMHead, flag)] & 0x3F
[INFO] [stdout]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     = note: ...which again requires borrow-checking `firmware::operation::implement::stm::gain::tests::test_phase_half`, completing the cycle
[INFO] [stdout]     = note: cycle used when running analysis passes on crate `autd3_driver`
[INFO] [stdout]     = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
[INFO] [stdout]     = note: this error originates in the macro `offset_of` (in Nightly builds, run with -Z macro-backtrace for more info)

https://crater-reports.s3.amazonaws.com/beta-1.93-3/beta-2025-12-09/reg/autd3-driver-38.0.1/log.txt

@rustbot modify labels: +regression-from-stable-to-beta -regression-untriaged

[theemathas]

MCVE:

use std::mem::offset_of;

struct Thing(i32);

pub fn foo() {
    let temp = [0u8];
    let _ = &(temp[offset_of!(Thing, 0)] & 0u8);
}

Error output

error[E0391]: cycle detected when borrow-checking `foo`
 --> src/lib.rs:5:1
  |
5 | pub fn foo() {
  | ^^^^^^^^^^^^
  |
note: ...which requires promoting constants in MIR for `foo`...
 --> src/lib.rs:5:1
  |
5 | pub fn foo() {
  | ^^^^^^^^^^^^
note: ...which requires simplifying constant for the type system `foo::{constant#0}`...
 --> src/lib.rs:7:20
  |
7 |     let _ = &(temp[offset_of!(Thing, 0)] & 0u8);
  |                    ^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating + checking `foo::{constant#0}`...
 --> src/lib.rs:7:20
  |
7 |     let _ = &(temp[offset_of!(Thing, 0)] & 0u8);
  |                    ^^^^^^^^^^^^^^^^^^^^
note: ...which requires caching mir of `foo::{constant#0}` for CTFE...
 --> src/lib.rs:7:20
  |
7 |     let _ = &(temp[offset_of!(Thing, 0)] & 0u8);
  |                    ^^^^^^^^^^^^^^^^^^^^
note: ...which requires elaborating drops for `foo::{constant#0}`...
 --> src/lib.rs:7:20
  |
7 |     let _ = &(temp[offset_of!(Thing, 0)] & 0u8);
  |                    ^^^^^^^^^^^^^^^^^^^^
  = note: ...which again requires borrow-checking `foo`, completing the cycle
  = note: cycle used when running analysis passes on crate `playground`
  = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
  = note: this error originates in the macro `offset_of` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0391`.