rust/src/test/ui/destructure-trait-ref.rs

56 lines
1.8 KiB
Rust

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// The regression test for #15031 to make sure destructuring trait
// reference work properly.
#![feature(box_patterns)]
#![feature(box_syntax)]
trait T { fn foo(&self) {} }
impl T for isize {}
fn main() {
// For an expression of the form:
//
// let &...&x = &..&SomeTrait;
//
// Say we have n `&` at the left hand and m `&` right hand, then:
// if n < m, we are golden;
// if n == m, it's a derefing non-derefable type error;
// if n > m, it's a type mismatch error.
// n < m
let &x = &(&1isize as &T);
let &x = &&(&1isize as &T);
let &&x = &&(&1isize as &T);
// n == m
let &x = &1isize as &T; //~ ERROR type `&dyn T` cannot be dereferenced
let &&x = &(&1isize as &T); //~ ERROR type `&dyn T` cannot be dereferenced
let box x = box 1isize as Box<T>; //~ ERROR type `std::boxed::Box<dyn T>` cannot be dereferenced
// n > m
let &&x = &1isize as &T;
//~^ ERROR mismatched types
//~| expected type `dyn T`
//~| found type `&_`
//~| expected trait T, found reference
let &&&x = &(&1isize as &T);
//~^ ERROR mismatched types
//~| expected type `dyn T`
//~| found type `&_`
//~| expected trait T, found reference
let box box x = box 1isize as Box<T>;
//~^ ERROR mismatched types
//~| expected type `dyn T`
//~| found type `std::boxed::Box<_>`
}