diff options
Diffstat (limited to 'tests/ui/traits/trait-upcasting')
3 files changed, 49 insertions, 7 deletions
diff --git a/tests/ui/traits/trait-upcasting/alias-where-clause-isnt-supertrait.rs b/tests/ui/traits/trait-upcasting/alias-where-clause-isnt-supertrait.rs new file mode 100644 index 000000000..4a5e445d1 --- /dev/null +++ b/tests/ui/traits/trait-upcasting/alias-where-clause-isnt-supertrait.rs @@ -0,0 +1,33 @@ +#![feature(trait_upcasting)] +#![feature(trait_alias)] + +// Although we *elaborate* `T: Alias` to `i32: B`, we should +// not consider `B` to be a supertrait of the type. +trait Alias = A where i32: B; + +trait A {} + +trait B { + fn test(&self); +} + +trait C: Alias {} + +impl A for () {} + +impl C for () {} + +impl B for i32 { + fn test(&self) { + println!("hi {self}"); + } +} + +fn test(x: &dyn C) -> &dyn B { + x + //~^ ERROR mismatched types +} + +fn main() { + let x: &dyn C = &(); +} diff --git a/tests/ui/traits/trait-upcasting/alias-where-clause-isnt-supertrait.stderr b/tests/ui/traits/trait-upcasting/alias-where-clause-isnt-supertrait.stderr new file mode 100644 index 000000000..5574a0320 --- /dev/null +++ b/tests/ui/traits/trait-upcasting/alias-where-clause-isnt-supertrait.stderr @@ -0,0 +1,14 @@ +error[E0308]: mismatched types + --> $DIR/alias-where-clause-isnt-supertrait.rs:27:5 + | +LL | fn test(x: &dyn C) -> &dyn B { + | ------ expected `&dyn B` because of return type +LL | x + | ^ expected trait `B`, found trait `C` + | + = note: expected reference `&dyn B` + found reference `&dyn C` + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0308`. diff --git a/tests/ui/traits/trait-upcasting/cyclic-trait-resolution.stderr b/tests/ui/traits/trait-upcasting/cyclic-trait-resolution.stderr index 15faab16a..ca98e1831 100644 --- a/tests/ui/traits/trait-upcasting/cyclic-trait-resolution.stderr +++ b/tests/ui/traits/trait-upcasting/cyclic-trait-resolution.stderr @@ -1,15 +1,10 @@ error[E0391]: cycle detected when computing the super predicates of `A` - --> $DIR/cyclic-trait-resolution.rs:1:1 - | -LL | trait A: B + A {} - | ^^^^^^^^^^^^^^ - | -note: ...which requires computing the super traits of `A`... --> $DIR/cyclic-trait-resolution.rs:1:14 | LL | trait A: B + A {} | ^ - = note: ...which again requires computing the super predicates of `A`, completing the cycle + | + = note: ...which immediately requires computing the super predicates of `A` again note: cycle used when collecting item types in top-level module --> $DIR/cyclic-trait-resolution.rs:1:1 | |