tests/ui/rust-2021/future-prelude-collision.fixed

   1 // run-rustfix
   2 // edition:2018
   3 // check-pass
   4 #![warn(rust_2021_prelude_collisions)]
   5
   6 trait TryIntoU32 {
   7     fn try_into(self) -> Result<u32, ()>;
   8 }
   9
  10 impl TryIntoU32 for u8 {
  11     fn try_into(self) -> Result<u32, ()> {
  12         Ok(self as u32)
  13     }
  14 }
  15
  16 // needed for autoref test
  17 impl TryIntoU32 for &f32 {
  18     fn try_into(self) -> Result<u32, ()> {
  19         Ok(*self as u32)
  20     }
  21 }
  22
  23 trait TryFromU8: Sized {
  24     fn try_from(x: u8) -> Result<Self, ()>;
  25 }
  26
  27 impl TryFromU8 for u32 {
  28     fn try_from(x: u8) -> Result<Self, ()> {
  29         Ok(x as u32)
  30     }
  31 }
  32
  33 impl TryIntoU32 for *const u16 {
  34     fn try_into(self) -> Result<u32, ()> {
  35         Ok(unsafe { *self } as u32)
  36     }
  37 }
  38
  39 trait FromByteIterator {
  40     fn from_iter<T>(iter: T) -> Self
  41     where
  42         T: Iterator<Item = u8>;
  43 }
  44
  45 impl FromByteIterator for Vec<u8> {
  46     fn from_iter<T>(iter: T) -> Self
  47     where
  48         T: Iterator<Item = u8>,
  49     {
  50         iter.collect()
  51     }
  52 }
  53
  54 fn main() {
  55     // test dot-call that will break in 2021 edition
  56     let _: u32 = TryIntoU32::try_into(3u8).unwrap();
  57     //~^ WARNING trait method `try_into` will become ambiguous in Rust 2021
  58     //~^^ WARNING this is accepted in the current edition
  59
  60     // test associated function call that will break in 2021 edition
  61     let _ = <u32 as TryFromU8>::try_from(3u8).unwrap();
  62     //~^ WARNING trait-associated function `try_from` will become ambiguous in Rust 2021
  63     //~^^ WARNING this is accepted in the current edition
  64
  65     // test reverse turbofish too
  66     let _ = <Vec<u8> as FromByteIterator>::from_iter(vec![1u8, 2, 3, 4, 5, 6].into_iter());
  67     //~^ WARNING trait-associated function `from_iter` will become ambiguous in Rust 2021
  68     //~^^ WARNING this is accepted in the current edition
  69
  70     // negative testing lint (this line should *not* emit a warning)
  71     let _: u32 = TryFromU8::try_from(3u8).unwrap();
  72
  73     // test type omission
  74     let _: u32 = <_ as TryFromU8>::try_from(3u8).unwrap();
  75     //~^ WARNING trait-associated function `try_from` will become ambiguous in Rust 2021
  76     //~^^ WARNING this is accepted in the current edition
  77
  78     // test autoderef
  79     let _: u32 = TryIntoU32::try_into(*(&3u8)).unwrap();
  80     //~^ WARNING trait method `try_into` will become ambiguous in Rust 2021
  81     //~^^ WARNING this is accepted in the current edition
  82
  83     // test autoref
  84     let _: u32 = TryIntoU32::try_into(&3.0).unwrap();
  85     //~^ WARNING trait method `try_into` will become ambiguous in Rust 2021
  86     //~^^ WARNING this is accepted in the current edition
  87
  88     let mut data = 3u16;
  89     let mut_ptr = std::ptr::addr_of_mut!(data);
  90     let _: u32 = TryIntoU32::try_into(mut_ptr as *const _).unwrap();
  91     //~^ WARNING trait method `try_into` will become ambiguous in Rust 2021
  92     //~^^ WARNING this is accepted in the current edition
  93
  94     type U32Alias = u32;
  95     let _ = <U32Alias as TryFromU8>::try_from(3u8).unwrap();
  96     //~^ WARNING trait-associated function `try_from` will become ambiguous in Rust 2021
  97     //~^^ WARNING this is accepted in the current edition
  98 }