ICE in link_staticlib: called Result::unwrap() on an Err value: Os { code: 2, kind: NotFound, message: No such file or directory }

Summary

Incremental compilation of a crate with crate-type = ["lib", "cdylib", "staticlib"] panics in link_staticlib → each_linked_rlib → add_archive() with ENOENT. The stale rlib path persists from a prior compilation cycle.

Steps to Reproduce

1. cargo new ice-repro && cd ice-repro
2. Add crc-fast = "=1.8.0" to [dependencies] in Cargo.toml
3. cargo check (creates incremental metadata)
4. cargo clean -p ice-repro (cleans only the top crate, not deps)
5. cargo build (triggers incremental rebuild of crc-fast which has crate-type = ["lib", "cdylib", "staticlib"])

Alternatively, use this Cargo.toml:

[package]
name = "ice-repro"
version = "0.1.0"
edition = "2024"

[dependencies]
crc-fast = "=1.8.0"

The ICE is intermittent (~50% occurrence in the observed workspace).

Meta

rustc --version --verbose:

rustc 1.95.0 (59807616e 2026-04-14)
binary: rustc
commit-hash: 59807616e1fa2540724bfbac14d7976d7e4a3860
commit-date: 2026-04-14
host: x86_64-unknown-linux-gnu
release: 1.95.0
LLVM version: 20.1.4

Error Output

thread 'rustc' (1111947) panicked at /rustc-dev/59807616e1fa2540724bfbac14d7976d7e4a3860/compiler/rustc_codegen_ssa/src/back/link.rs:509:14:
called `Result::unwrap()` on an `Err` value: Os { code: 2, kind: NotFound, message: "No such file or directory" }

Full backtrace:

   0:     0x7fc469f9314b - <<std[e28293b1aa0f68bd]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[c1f1a4ba060b9bfa]::fmt::Display>::fmt
   1:     0x7fc46a61f408 - core[c1f1a4ba060b9bfa]::fmt::write
   2:     0x7fc46bb683b6 - <std[e28293b1aa0f68bd]::sys::stdio::unix::Stderr as std[e28293b1aa0f68bd]::io::Write>::write_fmt
   3:     0x7fc469f69238 - std[e28293b1aa0f68bd]::panicking::default_hook::{closure#0}
   4:     0x7fc469f865b3 - std[e28293b1aa0f68bd]::panicking::default_hook
   5:     0x7fc468f5cc30 - std[e28293b1aa0f68bd]::panicking::update_hook::<alloc[fdfd2bd8633a6659]::boxed::Box<rustc_driver_impl[e4ca9dd5dd6cf2a8]::install_ice_hook::{closure#1}>>::{closure#0}
   6:     0x7fc469f86892 - std[e28293b1aa0f68bd]::panicking::panic_with_hook
   7:     0x7fc469f692f8 - std[e28293b1aa0f68bd]::panicking::panic_handler::{closure#0}
   8:     0x7fc469f60029 - std[e28293b1aa0f68bd]::sys::backtrace::__rust_end_short_backtrace::<std[e28293b1aa0f68bd]::panicking::panic_handler::{closure#0}, !>
   9:     0x7fc469f6ad5d - __rustc[b7974e8690430dd9]::rust_begin_unwind
  10:     0x7fc466cde82c - core[c1f1a4ba060b9bfa]::panicking::panic_fmt
  11:     0x7fc4667076f2 - core[c1f1a4ba060b9bfa]::result::unwrap_failed
  12:     0x7fc468dc368a - rustc_codegen_ssa[fd5ecd340cdb7a09]::back::link::link_staticlib::{closure#0}
  13:     0x7fc46b96e27b - rustc_codegen_ssa[fd5ecd340cdb7a09]::back::link::each_linked_rlib
  14:     0x7fc46b5c1024 - rustc_codegen_ssa[fd5ecd340cdb7a09]::back::link::link_binary
  15:     0x7fc46b5bf8a9 - <rustc_codegen_llvm[3c18e353d9a32df8]::LlvmCodegenBackend as rustc_codegen_ssa[fd5ecd340cdb7a09]::traits::backend::CodegenBackend>::link
  16:     0x7fc46b97807b - <rustc_interface[c8170c4b7b680ee8]::queries::Linker>::link
  17:     0x7fc46b85651a - rustc_interface[c8170c4b7b680ee8]::interface::run_compiler::<(), rustc_driver_impl[e4ca9dd5dd6cf2a8]::run_compiler::{closure#0}>::{closure#1}
  18:     0x7fc46b82663e - std[e28293b1aa0f68bd]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[c8170c4b7b680ee8]::util::run_in_thread_with_globals<rustc_interface[c8170c4b7b680ee8]::util::run_in_thread_pool_with_globals<rustc_interface[c8170c4b7b680ee8]::interface::run_compiler<(), rustc_driver_impl[e4ca9dd5dd6cf2a8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  19:     0x7fc46b826ca0 - <std[e28293b1aa0f68bd]::thread::lifecycle::spawn_unchecked<rustc_interface[c8170c4b7b680ee8]::util::run_in_thread_with_globals<rustc_interface[c8170c4b7b680ee8]::util::run_in_thread_pool_with_globals<rustc_interface[c8170c4b7b680ee8]::interface::run_compiler<(), rustc_driver_impl[e4ca9dd5dd6cf2a8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[c1f1a4ba060b9bfa]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  20:     0x7fc46b827b2c - <std[e28293b1aa0f68bd]::sys::thread::unix::Thread>::new::thread_start
  21:     0x7fc4650981b9 - <unknown>
  22:     0x7fc46511d21c - <unknown>
  23:                0x0 - <unknown>

Compiler Flags

--crate-type lib --crate-type cdylib --crate-type staticlib -C embed-bitcode=no -C debuginfo=2

Notes

• The crc-fast crate declares crate-type = ["lib", "cdylib", "staticlib"] to produce a C-compatible shared library alongside the Rust lib.
• The panic occurs at link.rs:509 in link_staticlib when each_linked_rlib returns a path to an rlib that no longer exists on disk (stale incremental-cache reference).
• The same thread ID (1111947) appeared consistently across runs, suggesting deterministic behavior based on the incremental cache state.
• Does NOT trigger on rustc 1.94.0.
• The add_archive(path).unwrap() at link.rs:509 should handle this gracefully (e.g. expect with a descriptive message, or skip missing rlibs).

Reproduce the ICE with the provided cargo new, cargo check, cargo clean -p, and cargo build sequence. Read compiler/rustc_codegen_ssa/src/back/link.rs around link_staticlib, each_linked_rlib, and add_archive(), where the stale rlib path is reported. Done means the reproduction no longer panics when that rlib is missing and the failure is handled gracefully.