The unwind attribute was malformed.
Erroneous code example:
#![feature(unwind_attributes)]
#[unwind()] // error: expected one argument
pub extern "C" fn something() {}
fn main() {}The #[unwind] attribute should be used as follows:
#[unwind(aborts)] – specifies that if a non-Rust ABI function
should abort the process if it attempts to unwind. This is the safer
and preferred option.
#[unwind(allowed)] – specifies that a non-Rust ABI function
should be allowed to unwind. This can easily result in Undefined
Behavior (UB), so be careful.
NB. The default behavior here is “allowed”, but this is unspecified and likely to change in the future.