rust/src/test/compile-fail/trait-suggest-where-clause.rs

70 lines
2.8 KiB
Rust

// Copyright 2016 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.
use std::mem;
struct Misc<T:?Sized>(T);
fn check<T: Iterator, U: ?Sized>() {
// suggest a where-clause, if needed
mem::size_of::<U>();
//~^ ERROR `U: std::marker::Sized` is not satisfied
//~| HELP consider adding a `where U: std::marker::Sized` bound
//~| NOTE required by `std::mem::size_of`
//~| NOTE `U` does not have a constant size known at compile-time
//~| HELP the trait `std::marker::Sized` is not implemented for `U`
mem::size_of::<Misc<U>>();
//~^ ERROR `U: std::marker::Sized` is not satisfied
//~| HELP consider adding a `where U: std::marker::Sized` bound
//~| NOTE required because it appears within the type `Misc<U>`
//~| NOTE required by `std::mem::size_of`
//~| NOTE `U` does not have a constant size known at compile-time
//~| HELP within `Misc<U>`, the trait `std::marker::Sized` is not implemented for `U`
// ... even if T occurs as a type parameter
<u64 as From<T>>::from;
//~^ ERROR `u64: std::convert::From<T>` is not satisfied
//~| HELP consider adding a `where u64: std::convert::From<T>` bound
//~| NOTE required by `std::convert::From::from`
//~| NOTE the trait `std::convert::From<T>` is not implemented for `u64`
<u64 as From<<T as Iterator>::Item>>::from;
//~^ ERROR `u64: std::convert::From<<T as std::iter::Iterator>::Item>` is not satisfied
//~| HELP consider adding a `where u64:
//~| NOTE required by `std::convert::From::from`
//~| NOTE the trait `std::convert::From<<T as std::iter::Iterator>::Item>` is not implemented
// ... but not if there are inference variables
<Misc<_> as From<T>>::from;
//~^ ERROR `Misc<_>: std::convert::From<T>` is not satisfied
//~| NOTE required by `std::convert::From::from`
//~| NOTE the trait `std::convert::From<T>` is not implemented for `Misc<_>`
// ... and also not if the error is not related to the type
mem::size_of::<[T]>();
//~^ ERROR `[T]: std::marker::Sized` is not satisfied
//~| NOTE `[T]` does not have a constant size
//~| NOTE required by `std::mem::size_of`
//~| HELP the trait `std::marker::Sized` is not implemented for `[T]`
mem::size_of::<[&U]>();
//~^ ERROR `[&U]: std::marker::Sized` is not satisfied
//~| NOTE `[&U]` does not have a constant size
//~| NOTE required by `std::mem::size_of`
//~| HELP the trait `std::marker::Sized` is not implemented for `[&U]`
}
fn main() {
}