src/test/ui/associated-types/issue-87261.rs

   1 trait Foo {}
   2
   3 trait Trait {
   4     type Associated;
   5 }
   6 trait DerivedTrait: Trait {}
   7 trait GenericTrait<A> {
   8     type Associated;
   9 }
  10
  11 struct Impl;
  12 impl Foo for Impl {}
  13 impl Trait for Impl {
  14     type Associated = ();
  15 }
  16 impl DerivedTrait for Impl {}
  17 impl<A> GenericTrait<A> for Impl {
  18     type Associated = ();
  19 }
  20
  21 fn returns_opaque() -> impl Trait + 'static {
  22     Impl
  23 }
  24 fn returns_opaque_derived() -> impl DerivedTrait + 'static {
  25     Impl
  26 }
  27 fn returns_opaque_foo() -> impl Trait + Foo {
  28     Impl
  29 }
  30 fn returns_opaque_derived_foo() -> impl DerivedTrait + Foo {
  31     Impl
  32 }
  33 fn returns_opaque_generic() -> impl GenericTrait<()> + 'static {
  34     Impl
  35 }
  36 fn returns_opaque_generic_foo() -> impl GenericTrait<()> + Foo {
  37     Impl
  38 }
  39 fn returns_opaque_generic_duplicate() -> impl GenericTrait<()> + GenericTrait<u8> {
  40     Impl
  41 }
  42
  43 fn accepts_trait<T: Trait<Associated = ()>>(_: T) {}
  44 fn accepts_generic_trait<T: GenericTrait<(), Associated = ()>>(_: T) {}
  45
  46 fn check_generics<A, B, C, D, E, F, G>(a: A, b: B, c: C, d: D, e: E, f: F, g: G)
  47 where
  48     A: Trait + 'static,
  49     B: DerivedTrait + 'static,
  50     C: Trait + Foo,
  51     D: DerivedTrait + Foo,
  52     E: GenericTrait<()> + 'static,
  53     F: GenericTrait<()> + Foo,
  54     G: GenericTrait<()> + GenericTrait<u8>,
  55 {
  56     accepts_trait(a);
  57     //~^ ERROR type mismatch resolving `<A as Trait>::Associated == ()`
  58
  59     accepts_trait(b);
  60     //~^ ERROR type mismatch resolving `<B as Trait>::Associated == ()`
  61
  62     accepts_trait(c);
  63     //~^ ERROR type mismatch resolving `<C as Trait>::Associated == ()`
  64
  65     accepts_trait(d);
  66     //~^ ERROR type mismatch resolving `<D as Trait>::Associated == ()`
  67
  68     accepts_generic_trait(e);
  69     //~^ ERROR type mismatch resolving `<E as GenericTrait<()>>::Associated == ()`
  70
  71     accepts_generic_trait(f);
  72     //~^ ERROR type mismatch resolving `<F as GenericTrait<()>>::Associated == ()`
  73
  74     accepts_generic_trait(g);
  75     //~^ ERROR type mismatch resolving `<G as GenericTrait<()>>::Associated == ()`
  76 }
  77
  78 fn main() {
  79     accepts_trait(returns_opaque());
  80     //~^ ERROR type mismatch resolving `<impl Trait as Trait>::Associated == ()`
  81
  82     accepts_trait(returns_opaque_derived());
  83     //~^ ERROR type mismatch resolving `<impl DerivedTrait as Trait>::Associated == ()`
  84
  85     accepts_trait(returns_opaque_foo());
  86     //~^ ERROR type mismatch resolving `<impl Trait + Foo as Trait>::Associated == ()`
  87
  88     accepts_trait(returns_opaque_derived_foo());
  89     //~^ ERROR type mismatch resolving `<impl DerivedTrait + Foo as Trait>::Associated == ()`
  90
  91     accepts_generic_trait(returns_opaque_generic());
  92     //~^ ERROR type mismatch resolving `<impl GenericTrait<()> as GenericTrait<()>>::Associated == ()`
  93
  94     accepts_generic_trait(returns_opaque_generic_foo());
  95     //~^ ERROR type mismatch resolving `<impl GenericTrait<()> + Foo as GenericTrait<()>>::Associated == ()`
  96
  97     accepts_generic_trait(returns_opaque_generic_duplicate());
  98     //~^ ERROR type mismatch resolving `<impl GenericTrait<()> + GenericTrait<u8> as GenericTrait<()>>::Associated == ()`
  99 }