rust/src/test/ui/nested_impl_trait.rs
2018-12-25 21:08:33 -07:00

31 lines
782 B
Rust

use std::fmt::Debug;
fn fine(x: impl Into<u32>) -> impl Into<u32> { x }
fn bad_in_ret_position(x: impl Into<u32>) -> impl Into<impl Debug> { x }
//~^ ERROR nested `impl Trait` is not allowed
fn bad_in_fn_syntax(x: fn() -> impl Into<impl Debug>) {}
//~^ ERROR nested `impl Trait` is not allowed
//~^^ `impl Trait` not allowed
fn bad_in_arg_position(_: impl Into<impl Debug>) { }
//~^ ERROR nested `impl Trait` is not allowed
struct X;
impl X {
fn bad(x: impl Into<u32>) -> impl Into<impl Debug> { x }
//~^ ERROR nested `impl Trait` is not allowed
}
fn allowed_in_assoc_type() -> impl Iterator<Item=impl Fn()> {
vec![|| println!("woot")].into_iter()
}
fn allowed_in_ret_type() -> impl Fn() -> impl Into<u32> {
//~^ `impl Trait` not allowed
|| 5
}
fn main() {}