Upgrade the Rust toolchain to nightly-2026-10-11

[feliperodri]

Brings the pinned nightly from nightly-2026-09-25 to nightly-2026-10-11. The automated update has been failing since 09-26 (#4935). The range is about 1,500 rustc commits, but only a handful of changes affect Kani. One of them changes behaviour quietly, and it is the part worth reviewing.

The one that matters: use lists in HIR (rust-lang/rust#161349). rustc used to lower use a::{b, c}; into separate items, use a::b; and use a::c;. It now keeps a single item holding a tree of imports. Kani's path resolver (kani_middle/resolve.rs), which resolves the paths in #[kani::stub], contracts and related attributes, found imported names by scanning those per-name items. Updating only the pattern would have compiled, but every name imported through a {...} list would have stopped resolving. tests/kani/FunctionContracts/cross_module_multiple_impls.rs would have caught it, because it imports its contract targets with use crate::ty::{D, S};. The resolver now walks each use tree at every level, looking for the name and collecting globs, with the same precedence as before: a named import wins over globs. The new tests/kani/Stubbing/resolve_use_nested.rs stubs through a list, a rename inside a list, a glob inside a list, and a list nested in a list. It passes on nightly-2026-09-25 as well, and on the new toolchain it fails with failed to resolve for four of its seven stubs if the walk doesn't recurse.

Mechanical API updates:

• rustc_hir no longer re-exports the attribute crate (Remove rustc_hir's attribute re-exports rust-lang/rust#163250): Attribute, AttrArgs and LangItem now come from rustc_attr_ir.
• rustc_driver::run_compiler is now compiler_entrypoint (Rename rustc_driver::run_compiler to compiler_entrypoint rust-lang/rust#163647).
• mir::Terminator::attributes is now loop_hint_attrs. It holds #[unroll] hints, which Kani-built terminators don't carry.
• The type_id intrinsic moved to core::intrinsics::reflection. I also fixed the needs_drop panic message, which wrongly named type_id.
• In nightly-2026-10-11, loop_hint_attrs moved again, from Terminator into TerminatorKind::Goto (Move loop_hint_attrs from Terminator into TerminatorKind::Goto rust-lang/rust#163931).
• rustc_abi::Float gained PpcF128 (add IBM f128 type rust-lang/rust#162156), PowerPC's double-double long double. It only exists on PowerPC targets, which Kani doesn't support, so it is reported as unsupported, like the existing F16B case.

Test updates. Importing copy, copy_nonoverlapping and write_bytes through the accidentally stabilized core::intrinsics path is now a deny-by-default lint (rust-lang/rust#163160). Fifteen tests did that. They check Kani's model of the intrinsics themselves, and the core::ptr versions add extra debug assertions on top, so the tests now opt in to core_intrinsics instead of switching to ptr. Their expected output is unchanged.

Test updates, continued. rustc's diagnostic for ui/ice-size-overflow/large_array.rs now also prints the enclosing SizedTypeProperties trait line, so its expected output gains two lines. Kani still reports the same E0080 there, without crashing.

Testing. I ran scripts/kani-regression.sh and scripts/kani-llbc-regression.sh locally on nightly-2026-10-11 (Linux x86_64, CBMC 6.11.0), with main merged in, plus fmt and the three clippy gates (workspace, --cfg=kani_sysroot, --features llbc). Every suite passes. Charon builds unchanged. Locally I cap CBMC at 6 GB, which makes push_slow.rs and cell_stub.rs run out of memory on main as well; uncapped, both pass here. I also checked the other rustc_public changes in the range: PassMode::IndirectUnsized (Kani only compares against PassMode::Ignore) and a docs-only pointee-size change. Neither affects Kani.

The earlier CI failures on this PR were the zerocopy 0.8.60 break (#4988), which zerocopy fixed in 0.8.61; the rerun on the previous head passed on Linux and macOS-14.

Resolves #4935

[Copilot]

Copilot review overview

🔵 Needs a closer look

The compiler-private API and import-resolution changes warrant human confirmation of cross-platform and backend regression results.

Review effort: Balanced
Findings: None

What changed in this PR

Upgrades Kani to nightly-2026-10-06, addressing #4935 while preserving import resolution for stubs and contracts.

Changes:

• Updates compiler-private APIs and the pinned toolchain.
• Recursively resolves import trees, with regression coverage for nested lists, renames, and globs.
• Enables intrinsic feature gates in affected tests and updates type_id usage and diagnostics.

File	Description
tests/​kani/​Stubbing/​resolve_use_nested.rs	Tests stubbing through nested imports.
tests/​kani/​Intrinsics/​Copy/​copy.rs	Enables direct intrinsic testing.
tests/​kani/​Intrinsics/​Copy/​copy_nonoverlapping.rs	Enables direct intrinsic testing.
tests/​kani/​Intrinsics/​ConstEval/​type_id.rs	Updates the type_id import.
tests/​expected/​valid-value-checks/​write_invalid.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​write_bytes/​unaligned/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy/​copy-unwritable-dst/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy/​copy-unreadable-src/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy/​copy-unaligned-src/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy/​copy-unaligned-dst/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy/​copy-overflow/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy-nonoverlapping/​copy-unwritable-dst/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy-nonoverlapping/​copy-unreadable-src/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy-nonoverlapping/​copy-unaligned-src/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy-nonoverlapping/​copy-unaligned-dst/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy-nonoverlapping/​copy-overlapping/​main.rs	Enables intrinsic feature gates.
tests/​expected/​intrinsics/​copy-nonoverlapping/​copy-overflow/​main.rs	Enables intrinsic feature gates.
rust-toolchain.toml	Pins the newer nightly.
kani-compiler/​src/​main.rs	Updates compiler entrypoint and crate imports.
kani-compiler/​src/​kani_middle/​transform/​rustc_intrinsics.rs	Updates the LangItem import.
kani-compiler/​src/​kani_middle/​transform/​internal_mir.rs	Adopts loop_hint_attrs.
kani-compiler/​src/​kani_middle/​resolve.rs	Traverses import trees recursively.
kani-compiler/​src/​kani_middle/​coercion.rs	Updates the LangItem import.
kani-compiler/​src/​kani_middle/​attributes.rs	Updates attribute imports and documentation.
kani-compiler/​src/​kani_compiler.rs	Uses the renamed compiler entrypoint.
kani-compiler/​src/​intrinsics.rs	Corrects intrinsic panic messages.
kani-compiler/​src/​codegen_cprover_gotoc/​overrides/​hooks.rs	Updates the LangItem import.
kani-compiler/​src/​codegen_cprover_gotoc/​codegen/​span.rs	Updates the Attribute import.
kani-compiler/​src/​codegen_aeneas_llbc/​mir_to_ullbc/​mod.rs	Updates LLBC’s LangItem reference.

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