tests/ui/borrowck/trait-impl-argument-difference-ice.rs

// Issue https://github.com/rust-lang/rust/issues/123414
trait MemoryUnit {
    extern "C" fn read_word(&mut self) -> u8;
    extern "C" fn read_dword(Self::Assoc<'_>) -> u16;
    //~^ WARNING anonymous parameters are deprecated and will be removed in the next edition
    //~| WARNING this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2018!
    //~| ERROR associated type `Assoc` not found for `Self`
}

struct ROM {}

impl MemoryUnit for ROM {
//~^ ERROR not all trait items implemented, missing: `read_word`
    extern "C" fn read_dword(&'_ self) -> u16 {
        //~^ ERROR method `read_dword` has a `&self` declaration in the impl, but not in the trait
        let a16 = self.read_word() as u16;
        //~^ ERROR cannot borrow `*self` as mutable, as it is behind a `&` reference
        let b16 = self.read_word() as u16;
        //~^ ERROR cannot borrow `*self` as mutable, as it is behind a `&` reference

        (b16 << 8) | a16
    }
}

pub fn main() {}