type ascription: stack overflow #149431
Description
Code
const ARRAY_REF: [!; 1] = todo!(); fn main() { type_ascribe!(ARRAY_REF[0], i32) }Meta
rustc --version --verbose:
rustc 1.93.0-nightly (c86564c41 2025-11-27) binary: rustc commit-hash: c86564c412a5949088a53b665d8b9a47ec610a39 commit-date: 2025-11-27 host: x86_64-unknown-linux-gnu release: 1.93.0-nightly LLVM version: 21.1.5 Error output
error[E0658]: use of unstable library feature `type_ascription`: placeholder syntax for type ascription --> code.rs:3:5 | 3 | type_ascribe!(ARRAY_REF[0], i32) | ^^^^^^^^^^^^ | = note: see issue #23416 <https://github.com/rust-lang/rust/issues/23416> for more information = help: add `#![feature(type_ascription)]` to the crate attributes to enable = note: this compiler was built on 2025-11-27; consider upgrading it if it is out of date error[E0658]: the `!` type is experimental --> code.rs:1:19 | 1 | const ARRAY_REF: [!; 1] = todo!(); | ^ | = note: see issue #35121 <https://github.com/rust-lang/rust/issues/35121> for more information = help: add `#![feature(never_type)]` to the crate attributes to enable = note: this compiler was built on 2025-11-27; consider upgrading it if it is out of date error[E0080]: evaluation panicked: not yet implemented --> code.rs:1:27 | 1 | const ARRAY_REF: [!; 1] = todo!(); | ^^^^^^^ evaluation of `ARRAY_REF` failed here | Backtrace
error: rustc interrupted by SIGSEGV, printing backtrace /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x3ad574c) [0x7f7a54ad574c] /usr/lib/libc.so.6(+0x3e540) [0x7f7a50c3e540] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(_RNvMs1_NtNtCshPD3nR7tEK4_12rustc_middle3hir3mapNtNtNtB9_2ty7context6TyCtxt15parent_hir_node+0x2b) [0x7f7a5629e7fd] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56030eb) [0x7f7a566030eb] ### cycle encountered after 4 frames with period 5 /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] ### recursed 50 times /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-d012d9d43742cddd.so(+0x56032ee) [0x7f7a566032ee] note: rustc unexpectedly overflowed its stack! this is a bug note: maximum backtrace depth reached, frames may have been lost note: we would appreciate a report at https://github.com/rust-lang/rust help: you can increase rustc's stack size by setting RUST_MIN_STACK=16777216 [1] 4073700 segmentation fault rustc code.rs