rust/tests/ui/rfcs/rfc-2632-const-trait-impl/unsatisfied-const-trait-bound.rs

34 lines
933 B
Rust

// Ensure that we print unsatisfied always-const trait bounds as `const Trait` in diagnostics.
#![feature(const_trait_impl, effects, generic_const_exprs)]
#![allow(incomplete_features)]
fn require<T: const Trait>() {}
#[const_trait]
trait Trait {
fn make() -> u32;
}
struct Ty;
impl Trait for Ty {
fn make() -> u32 { 0 }
}
fn main() {
require::<Ty>(); //~ ERROR the trait bound `Ty: const Trait` is not satisfied
}
struct Container<const N: u32>;
// FIXME(effects): Somehow emit `the trait bound `T: const Trait` is not satisfied` here instead
// and suggest changing `Trait` to `const Trait`.
fn accept0<T: Trait>(_: Container<{ T::make() }>) {}
//~^ ERROR mismatched types
// FIXME(effects): Instead of suggesting `+ const Trait`, suggest
// changing `~const Trait` to `const Trait`.
const fn accept1<T: ~const Trait>(_: Container<{ T::make() }>) {}
//~^ ERROR mismatched types