4 #![warn(rust_2021_prelude_collisions)]
7 fn from_iter(x: Option<A>);
10 impl<T> MyTrait<()> for Vec<T> {
11 fn from_iter(_: Option<()>) {}
15 <Vec<i32>>::from_iter(None);
16 //~^ WARNING trait-associated function `from_iter` will become ambiguous in Rust 2021
17 //~^^ WARNING this is accepted in the current edition