rust/tests/ui/traits/negative-impls/rely-on-negative-impl-in-co...

25 lines
620 B
Rust

//@ check-pass
#![feature(negative_impls)]
#![feature(with_negative_coherence)]
//@ aux-build: foreign_trait.rs
// Test that we cannot implement `LocalTrait` for `String`,
// even though there is a `String: !ForeignTrait` impl.
//
// This may not be the behavior we want long term, but it's the
// current semantics that we implemented so as to land `!Foo` impls
// quickly. See internals thread:
//
// https://internals.rust-lang.org/t/foo/11587/
extern crate foreign_trait;
use foreign_trait::ForeignTrait;
trait LocalTrait {}
impl<T: ForeignTrait> LocalTrait for T {}
impl LocalTrait for String {}
fn main() {}