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// The regression test for #15031 to make sure destructuring trait
// reference work properly.
//@ dont-require-annotations: NOTE
#![feature(box_patterns)]
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 &dyn T);
let &x = &&(&1isize as &dyn T);
let &&x = &&(&1isize as &dyn T);
// n == m
let &x = &1isize as &dyn T; //~ ERROR type `&dyn T` cannot be dereferenced
let &&x = &(&1isize as &dyn T); //~ ERROR type `&dyn T` cannot be dereferenced
let box x = Box::new(1isize) as Box<dyn T>;
//~^ ERROR type `Box<dyn T>` cannot be dereferenced
// n > m
let &&x = &1isize as &dyn T;
//~^ ERROR mismatched types
//~| NOTE expected trait object `dyn T`
//~| NOTE found reference `&_`
let &&&x = &(&1isize as &dyn T);
//~^ ERROR mismatched types
//~| NOTE expected trait object `dyn T`
//~| NOTE found reference `&_`
let box box x = Box::new(1isize) as Box<dyn T>;
//~^ ERROR mismatched types
//~| NOTE expected trait object `dyn T`
//~| NOTE found struct `Box<_>`
}
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