src/test/ui/traits/inheritance/repeated-supertrait-ambig.rs

   1 // Test a case of a trait which extends the same supertrait twice, but
   2 // with difference type parameters. Test then that when we don't give
   3 // enough information to pick between these, no selection is made. In
   4 // this particular case, the two choices are i64/u64 -- so when we use
   5 // an integer literal, we wind up falling this literal back to i32.
   6 // See also `run-pass/trait-repeated-supertrait.rs`.
   7
   8 trait CompareTo<T> {
   9     fn same_as(&self, t: T) -> bool;
  10 }
  11
  12 trait CompareToInts : CompareTo<i64> + CompareTo<u64> {
  13 }
  14
  15 impl CompareTo<i64> for i64 {
  16     fn same_as(&self, t: i64) -> bool { *self == t }
  17 }
  18
  19 impl CompareTo<u64> for i64 {
  20     fn same_as(&self, t: u64) -> bool { *self == (t as i64) }
  21 }
  22
  23 impl CompareToInts for i64 { }
  24
  25 fn with_obj(c: &dyn CompareToInts) -> bool {
  26     c.same_as(22) //~ ERROR `dyn CompareToInts: CompareTo<i32>` is not satisfied
  27 }
  28
  29 fn with_trait<C:CompareToInts>(c: &C) -> bool {
  30     c.same_as(22) //~ ERROR `C: CompareTo<i32>` is not satisfied
  31 }
  32
  33 fn with_ufcs1<C:CompareToInts>(c: &C) -> bool {
  34     <dyn CompareToInts>::same_as(c, 22) //~ ERROR `dyn CompareToInts: CompareTo<i32>` is not satisfi
  35 }
  36
  37 fn with_ufcs2<C:CompareToInts>(c: &C) -> bool {
  38     CompareTo::same_as(c, 22) //~ ERROR `C: CompareTo<i32>` is not satisfied
  39 }
  40
  41 fn main() {
  42     assert_eq!(22_i64.same_as(22), true); //~ ERROR `i64: CompareTo<i32>` is not satisfied
  43 }