mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-23 15:23:46 +00:00
34 lines
1.2 KiB
Rust
34 lines
1.2 KiB
Rust
// The purpose of this test is to demonstrate that duplicating object safe traits
|
|
// that are not auto-traits is rejected even though one could reasonably accept this.
|
|
|
|
// Some arbitrary object-safe trait:
|
|
trait Obj {}
|
|
|
|
// Demonstrate that recursive expansion of trait aliases doesn't affect stable behavior:
|
|
type _0 = dyn Obj + Obj;
|
|
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
|
|
|
|
// Some variations:
|
|
|
|
type _1 = dyn Send + Obj + Obj;
|
|
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
|
|
|
|
type _2 = dyn Obj + Send + Obj;
|
|
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
|
|
|
|
type _3 = dyn Obj + Send + Send; // But it is OK to duplicate auto traits.
|
|
|
|
// Take higher ranked types into account.
|
|
|
|
// Note that `'a` and `'b` are intentionally different to make sure we consider
|
|
// them semantically the same.
|
|
trait ObjL<'l> {}
|
|
type _4 = dyn for<'a> ObjL<'a> + for<'b> ObjL<'b>;
|
|
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
|
|
|
|
trait ObjT<T> {}
|
|
type _5 = dyn ObjT<for<'a> fn(&'a u8)> + ObjT<for<'b> fn(&'b u8)>;
|
|
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
|
|
|
|
fn main() {}
|