Description
The Rust linux-build job on main and pull requests deterministically hits a rustc internal compiler error before tests execute after the floating toolchain advanced from nightly-2026-07-13 to nightly-2026-07-14.
The panic occurs while compiling the lance-encoding test binary at rust/lance-encoding/src/encodings/logical/primitive/miniblock.rs:124:
attribute is missing tokens
rustc_test_entrypoint_marker
This was first noticed on #7766 and reproduces on the current default branch. Stable, MSRV, ARM, macOS, Windows, Python, Java, and integration jobs are unaffected.
This is an upstream compiler regression tracked by rust-lang/rust#159261 and introduced by rust-lang/rust#158854. The upstream fix is rust-lang/rust#159277, which is approved but has not shipped in a nightly yet.
Steps to reproduce
From the repository root, run:
cargo +nightly-2026-07-14 test --profile ci --locked -p lance-encoding --lib --no-run --features bitpacking,lz4,zstd
The command ICEs even without coverage instrumentation. Replacing the toolchain with nightly-2026-07-13 succeeds.
The same version boundary is visible in CI:
Both sides use cargo-llvm-cov 0.8.4, and the workflow, lockfile, and implicated test source did not change across the boundary.
Expected behavior
linux-build should compile the workspace test binaries and execute the test suite.
Proposed mitigation
Temporarily pin the linux-build job to nightly-2026-07-13 for both toolchain installation and the cargo +toolchain llvm-cov invocation. Restore the floating nightly after a dated nightly containing the upstream fix passes the minimal reproduction and the full linux-build job.
This pin is a CI mitigation, not the root fix. Disabling coverage or changing Lance test attributes would only mask the compiler bug.
Environment
- Lance:
main at 0acc51eb8f013985395bf3ac7f0ef4f8a23a377d
- CI: Ubuntu 24.04, x86_64
- Reproduced locally: macOS, aarch64
- Rust:
1.99.0-nightly (daf2e5e18 2026-07-13)
- Language binding: Rust
Description
The Rust
linux-buildjob onmainand pull requests deterministically hits a rustc internal compiler error before tests execute after the floating toolchain advanced fromnightly-2026-07-13tonightly-2026-07-14.The panic occurs while compiling the
lance-encodingtest binary atrust/lance-encoding/src/encodings/logical/primitive/miniblock.rs:124:This was first noticed on #7766 and reproduces on the current default branch. Stable, MSRV, ARM, macOS, Windows, Python, Java, and integration jobs are unaffected.
This is an upstream compiler regression tracked by rust-lang/rust#159261 and introduced by rust-lang/rust#158854. The upstream fix is rust-lang/rust#159277, which is approved but has not shipped in a nightly yet.
Steps to reproduce
From the repository root, run:
cargo +nightly-2026-07-14 test --profile ci --locked -p lance-encoding --lib --no-run --features bitpacking,lz4,zstdThe command ICEs even without coverage instrumentation. Replacing the toolchain with
nightly-2026-07-13succeeds.The same version boundary is visible in CI:
mainrun withnightly-2026-07-13(77cf889bc): https://github.com/lance-format/lance/actions/runs/29291361054mainrun withnightly-2026-07-14(daf2e5e18): https://github.com/lance-format/lance/actions/runs/29305541748mainrun with the same ICE: https://github.com/lance-format/lance/actions/runs/29355503317Both sides use
cargo-llvm-cov 0.8.4, and the workflow, lockfile, and implicated test source did not change across the boundary.Expected behavior
linux-buildshould compile the workspace test binaries and execute the test suite.Proposed mitigation
Temporarily pin the
linux-buildjob tonightly-2026-07-13for both toolchain installation and thecargo +toolchain llvm-covinvocation. Restore the floating nightly after a dated nightly containing the upstream fix passes the minimal reproduction and the fulllinux-buildjob.This pin is a CI mitigation, not the root fix. Disabling coverage or changing Lance test attributes would only mask the compiler bug.
Environment
mainat0acc51eb8f013985395bf3ac7f0ef4f8a23a377d1.99.0-nightly (daf2e5e18 2026-07-13)