Open saethlin opened 2 weeks ago
Looks like the lint calls is_value_unfrozen_expr
with the type of ATOMIC_TUPLE.0
(Vec<UnsafeCell<i32>>
), but it is passing the valtree of the whole const (a tuple), so the type does not match the valtree, however they need to match each other so that the function can correctly traverse the valtree.
Otherwise we run into this ICE here where the function thinks it's looking at struct Cap(usize);
and expecting a branch but it's already at the usize which is a leaf.
That specific repro seems to only ICE in nightly, probably because of #12691 where the lint was made stronger, but the root cause has existed for longer it seems. Smaller repro that also ICEs on stable:
use std::cell::Cell;
const C: ((i32, Cell<i32>), i32) = ((0, Cell::new(1)), 2);
fn main() {
let _x = &C.0;
}
Summary
reports:
The problem is this unwrap_branch: https://github.com/rust-lang/rust-clippy/blob/0ce07f61db8c9de51e6ecd38aa62eb3145417c0f/clippy_lints/src/non_copy_const.rs#L222-L223
Version
Figuring out what's broken here is blocking https://github.com/rust-lang/rust/pull/126793