| // Copyright 2022 The Fuchsia Authors |
| // |
| // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0 |
| // <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT |
| // license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option. |
| // This file may not be copied, modified, or distributed except according to |
| // those terms. |
| |
| include!("../../zerocopy-derive/tests/include.rs"); |
| |
| extern crate zerocopy; |
| |
| use util::NotZerocopy; |
| use zerocopy::{Immutable, IntoBytes}; |
| |
| fn main() { |
| // This is adapted from #1296, which includes the following text: |
| // |
| // The compiler errors when a type is missing Immutable are somewhat |
| // misleading, although I'm not sure there's much zerocopy can do about |
| // this. An example where the compiler recommends adding a reference |
| // rather than implementing Immutable (some were even more confusing than |
| // this): |
| // |
| // error[E0277]: the trait bound `virtio::wl::CtrlVfdNewDmabuf: zerocopy::Immutable` is not satisfied |
| // --> devices/src/virtio/wl.rs:317:20 |
| // | |
| // 317 | .write_obj(ctrl_vfd_new_dmabuf) |
| // | --------- ^^^^^^^^^^^^^^^^^^^ the trait `zerocopy::Immutable` is not implemented for `virtio::wl::CtrlVfdNewDmabuf` |
| // | | |
| // | required by a bound introduced by this call |
| // | |
| // note: required by a bound in `virtio::descriptor_utils::Writer::write_obj` |
| // --> devices/src/virtio/descriptor_utils.rs:536:25 |
| // | |
| // 536 | pub fn write_obj<T: Immutable + IntoBytes>(&mut self, val: T) -> io::Result<()> { |
| // | ^^^^^^^^^ required by this bound in `Writer::write_obj` |
| // help: consider borrowing here |
| // | |
| // 317 | .write_obj(&ctrl_vfd_new_dmabuf) |
| // | + |
| // 317 | .write_obj(&mut ctrl_vfd_new_dmabuf) |
| // | ++++ |
| // |
| // Taking the compiler's suggestion results in a different error with a |
| // recommendation to remove the reference (back to the original code). |
| // |
| // As of this writing, the described problem is still happening thanks to |
| // https://github.com/rust-lang/rust/issues/130563. We include this test so |
| // that we can capture the current behavior, but we will update it once that |
| // Rust issue is fixed. |
| Foo.write_obj(NotZerocopy(())); |
| } |
| |
| struct Foo; |
| |
| impl Foo { |
| fn write_obj<T: Immutable + IntoBytes>(&mut self, _val: T) {} |
| } |
