Verus track has verified NOTHING since 2026-09-11 — toolchain cannot find core/std, all 19 proofs fail in 0.1s

[avrabe]

What

Every Verus proof target fails on main, and has since at least b03a1797:

run	sha	result
2026-09-15T19:49	283224d8	failure
2026-09-15T16:21	e6c65cfb	failure
2026-09-15T15:53	de266599	failure
2026-09-13T08:37	39f802cd	failure
2026-09-11T17:42	69ed42cc	failure
2026-09-11T12:12	b03a1797	failure

Executed 19 out of 19 tests: 19 fail locally.

It is not the proofs

Each target fails in 0.1 s — they never run. The root error is
environmental:

error[E0463]: can't find crate for `core`
error[E0463]: can't find crate for `std`

The Verus toolchain on the runner cannot resolve the Rust standard library, so
every target dies during compilation before any verification happens.

Why this matters more than a red tick

This is the exact failure #364 and #377 were built to prevent. #364 enforced the
track after discovering "19 proofs were defined and NONE ever ran"; #377 found
the new gate "has never passed — and it was hiding 2 broken ones". The gate
now exists and is red, which is strictly better than green-and-empty — but the
outcome for the verification posture is the same: the Verus track is
currently evidence of nothing, and has been for four days.

Verus is not in the required-contexts set, so it has not blocked any merge
during that window.

Where to start

The failure is in toolchain resolution, not in any proof, so it is likely one
of: a rules_verus toolchain pin that no longer resolves its Rust sysroot, a
runner image change, or a --platforms/sysroot mismatch introduced when the
gate moved. Compare a passing run from before 2026-09-11 against 283224d8 —
the proofs themselves are unchanged across that boundary, which narrows it to
the environment.

Related: #397 — //:falcon-cascade has not built under Bazel since #393, so
the cascade's witness MC/DC coverage is also not being produced. Two toolchain
gates on main are currently dark.

Falsification

Wrong if bazel test //:relay_primitives_verus_test passes on current main in
CI.