mirror of https://github.com/rust-lang/rust
33 lines
994 B
Rust
33 lines
994 B
Rust
// Check that when there are vacuous predicates in the environment
|
|
// (which make a fn uncallable) we don't erroneously cache those and
|
|
// then consider them satisfied elsewhere. The current technique for
|
|
// doing this is to not use global caches when there is a chance that
|
|
// the environment contains such a predicate.
|
|
// We still error for `i32: Bar<u32>` pending #48214
|
|
|
|
trait Foo<X,Y>: Bar<X> {
|
|
}
|
|
|
|
trait Bar<X> { }
|
|
|
|
// We don't always check where clauses for sanity, but in this case
|
|
// wfcheck does report an error here:
|
|
fn vacuous<A>()
|
|
where i32: Foo<u32, A> //~ ERROR the trait bound `i32: Bar<u32>` is not satisfied
|
|
{
|
|
// ... the original intention was to check that we don't use that
|
|
// vacuous where clause (which could never be satisfied) to accept
|
|
// the following line and then mess up calls elsewhere.
|
|
require::<i32, u32>();
|
|
}
|
|
|
|
fn require<A,B>()
|
|
where A: Bar<B>
|
|
{
|
|
}
|
|
|
|
fn main() {
|
|
require::<i32, u32>();
|
|
//~^ ERROR `i32: Bar<u32>` is not satisfied
|
|
}
|