tests/ui/generic-associated-types/issue-93342.rs

   1 // check-pass
   2
   3 use std::marker::PhantomData;
   4
   5 pub trait Scalar: 'static {
   6     type RefType<'a>: ScalarRef<'a>;
   7 }
   8
   9 pub trait ScalarRef<'a>: 'a {}
  10
  11 impl Scalar for i32 {
  12     type RefType<'a> = i32;
  13 }
  14
  15 impl Scalar for String {
  16     type RefType<'a> = &'a str;
  17 }
  18
  19 impl Scalar for bool {
  20     type RefType<'a> = i32;
  21 }
  22
  23 impl<'a> ScalarRef<'a> for bool {}
  24
  25 impl<'a> ScalarRef<'a> for i32 {}
  26
  27 impl<'a> ScalarRef<'a> for &'a str {}
  28
  29 fn str_contains(a: &str, b: &str) -> bool {
  30     a.contains(b)
  31 }
  32
  33 pub struct BinaryExpression<A: Scalar, B: Scalar, O: Scalar, F>
  34 where
  35     F: Fn(A::RefType<'_>, B::RefType<'_>) -> O,
  36 {
  37     f: F,
  38     _phantom: PhantomData<(A, B, O)>,
  39 }
  40
  41 impl<A: Scalar, B: Scalar, O: Scalar, F> BinaryExpression<A, B, O, F>
  42 where
  43     F: Fn(A::RefType<'_>, B::RefType<'_>) -> O,
  44 {
  45     pub fn new(f: F) -> Self {
  46         Self {
  47             f,
  48             _phantom: PhantomData,
  49         }
  50     }
  51 }
  52
  53 fn main() {
  54     BinaryExpression::<String, String, bool, _>::new(str_contains);
  55 }