src/test/ui/rust-2021/future-prelude-collision-generic.rs

   1 // test for https://github.com/rust-lang/rust/issues/86940
   2 // run-rustfix
   3 // edition:2018
   4 // check-pass
   5 #![warn(rust_2021_prelude_collisions)]
   6 #![allow(dead_code)]
   7 #![allow(unused_imports)]
   8
   9 struct Generic<'a, U>(&'a U);
  10
  11 trait MyFromIter {
  12     fn from_iter(_: i32) -> Self;
  13 }
  14
  15 impl MyFromIter for Generic<'static, i32> {
  16     fn from_iter(_: i32) -> Self {
  17         todo!()
  18     }
  19 }
  20
  21 impl std::iter::FromIterator<i32> for Generic<'static, i32> {
  22     fn from_iter<T: IntoIterator<Item = i32>>(_: T) -> Self {
  23         todo!()
  24     }
  25 }
  26
  27 fn main() {
  28     Generic::from_iter(1);
  29     //~^ WARNING trait-associated function `from_iter` will become ambiguous in Rust 2021
  30     //~| this is accepted in the current edition (Rust 2018)
  31     Generic::<'static, i32>::from_iter(1);
  32     //~^ WARNING trait-associated function `from_iter` will become ambiguous in Rust 2021
  33     //~| this is accepted in the current edition (Rust 2018)
  34     Generic::<'_, _>::from_iter(1);
  35     //~^ WARNING trait-associated function `from_iter` will become ambiguous in Rust 2021
  36     //~| this is accepted in the current edition (Rust 2018)
  37 }