| // Copyright 2012 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. |
| |
| // Test that when we match a trait reference like `Foo<A>: Foo<_#0t>`, |
| // we unify with `_#0t` with `A`. In this code, if we failed to do |
| // that, then you get an unconstrained type-variable in `call`. |
| // |
| // Also serves as a regression test for issue #26952, though the test |
| // was derived from another reported regression with the same cause. |
| |
| use std::marker::PhantomData; |
| |
| trait Trait<A> { fn foo(&self); } |
| |
| struct Type<A> { a: PhantomData<A> } |
| |
| fn as_trait<A>(t: &Type<A>) -> &Trait<A> { loop { } } |
| |
| fn want<A,T:Trait<A>+?Sized>(t: &T) { } |
| |
| fn call<A>(p: Type<A>) { |
| let q = as_trait(&p); |
| want(q); // parameter A to `want` *would* be unconstrained |
| } |
| |
| fn main() { } |
