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trait Foo {}
impl<F> Foo for F where F: Fn(&i32) -> &i32 {}
fn take_foo(_: impl Foo) {}
fn main() {
take_foo(|a| a);
//~^ ERROR implementation of `FnOnce` is not general enough
//~| ERROR implementation of `Fn` is not general enough
take_foo(|a: &i32| a);
//~^ ERROR lifetime may not live long enough
//~| ERROR mismatched types
take_foo(|a: &i32| -> &i32 { a });
//~^ ERROR lifetime may not live long enough
//~| ERROR mismatched types
// OK
take_foo(identity(|a| a));
take_foo(identity(|a: &i32| a));
take_foo(identity(|a: &i32| -> &i32 { a }));
fn identity<F>(t: F) -> F
where
F: Fn(&i32) -> &i32,
{
t
}
}
|
