An unsupported naked function definition.
Erroneous code example:
#[unsafe(naked)]
pub extern "C" fn f() -> u32 {
42
}
The naked function must be defined using a single naked_asm! assembly block.
The execution must never fall through past the end of the assembly
code, so it must either return or diverge. The asm block can also
use att_syntax and raw options, but others options are not allowed.
The asm block must not contain any operands other than const and
sym.
For more information, please see RFC 2972.