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fn with_closure_expecting_fn_with_free_region<F>(_: F)
where
F: for<'a> FnOnce(fn(&'a u32), &i32),
{
}
fn with_closure_expecting_fn_with_bound_region<F>(_: F)
where
F: FnOnce(fn(&u32), &i32),
{
}
fn expect_free_supply_free_from_fn<'x>(x: &'x u32) {
// Here, the type given for `'x` "obscures" a region from the
// expected signature that is bound at closure level.
with_closure_expecting_fn_with_free_region(|x: fn(&'x u32), y| {});
//~^ ERROR lifetime may not live long enough
//~| ERROR lifetime may not live long enough
}
fn expect_free_supply_free_from_closure() {
// A variant on the previous test. Here, the region `'a` will be
// bound at the closure level, just as is expected, so no error
// results.
type Foo<'a> = fn(&'a u32);
with_closure_expecting_fn_with_free_region(|_x: Foo<'_>, y| {});
}
fn expect_free_supply_bound() {
// Here, we are given a function whose region is bound at closure level,
// but we expect one bound in the argument. Error results.
with_closure_expecting_fn_with_free_region(|x: fn(&u32), y| {});
//~^ ERROR mismatched types
}
fn expect_bound_supply_free_from_fn<'x>(x: &'x u32) {
// Here, we are given a `fn(&u32)` but we expect a `fn(&'x
// u32)`. In principle, this could be ok, but we demand equality.
with_closure_expecting_fn_with_bound_region(|x: fn(&'x u32), y| {});
//~^ ERROR mismatched types
}
fn expect_bound_supply_free_from_closure() {
// A variant on the previous test. Here, the region `'a` will be
// bound at the closure level, but we expect something bound at
// the argument level.
type Foo<'a> = fn(&'a u32);
with_closure_expecting_fn_with_bound_region(|x: Foo<'_>, y| {
//~^ ERROR mismatched types
});
}
fn expect_bound_supply_bound<'x>(x: &'x u32) {
// No error in this case. The supplied type supplies the bound
// regions, and hence we are able to figure out the type of `y`
// from the expected type
with_closure_expecting_fn_with_bound_region(|x: for<'z> fn(&'z u32), y| {});
}
fn main() {}
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