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#![feature(type_alias_impl_trait)]
//@ build-pass
trait Bar {
fn bar(&self);
}
type FooFn<B> = impl FnOnce(B);
#[define_opaque(FooFn)]
fn foo<B: Bar>() -> FooFn<B> {
fn mop<B: Bar>(bar: B) {
bar.bar()
}
mop as fn(B)
// function pointers don't have any obligations on them,
// thus the above compiles. It's obviously unsound to just
// procure a `FooFn` from the ether without making sure that
// the pointer is actually legal for all `B`
}
fn main() {
let boom: FooFn<u32> = unsafe { core::mem::zeroed() };
boom(42);
}
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