| // rust-lang/rust#57979 : the initial support for `impl Trait` didn't |
| // properly check syntax hidden behind an associated type projection. |
| // Here we test behavior of occurrences of `impl Trait` within an |
| // `impl Trait` in that context. |
| |
| mod allowed { |
| #![allow(nested_impl_trait)] |
| |
| pub trait Foo<T> { } |
| pub trait Bar { } |
| pub trait Quux { type Assoc; } |
| pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { } |
| } |
| |
| mod warned { |
| #![warn(nested_impl_trait)] |
| |
| pub trait Foo<T> { } |
| pub trait Bar { } |
| pub trait Quux { type Assoc; } |
| pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { } |
| //~^ WARN nested `impl Trait` is not allowed |
| //~| WARN will become a hard error in a future release! |
| } |
| |
| mod denied { |
| #![deny(nested_impl_trait)] |
| |
| pub trait Foo<T> { } |
| pub trait Bar { } |
| pub trait Quux { type Assoc; } |
| pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { } |
| //~^ ERROR nested `impl Trait` is not allowed |
| //~| WARN will become a hard error in a future release! |
| } |
| |
| fn main() { } |
