rust/tests/ui/const_prop/dont-propagate-generic-instance.rs

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// run-pass
// Makes sure we don't propagate generic instances of `Self: ?Sized` blanket impls.
// This is relevant when we have an overlapping impl and builtin dyn instance.
// See <https://github.com/rust-lang/rust/pull/114941> for more context.
trait Trait {
fn foo(&self) -> &'static str;
}
impl<T: ?Sized> Trait for T {
fn foo(&self) -> &'static str {
std::any::type_name::<T>()
}
}
const fn bar<T: ?Sized>() -> fn(&T) -> &'static str {
Trait::foo
// If const prop were to propagate the instance
}
fn main() {
assert_eq!("i32", bar::<dyn Trait>()(&1i32));
}