rust/tests/ui/fn/fn_def_coercion.rs
2024-04-24 10:05:32 +00:00

59 lines
1.6 KiB
Rust

//! Test that coercing between function items of the same function,
//! but with different generic args succeeds in typeck, but then fails
//! in borrowck when the lifetimes can't actually be merged.
fn foo<T>(t: T) -> T {
t
}
fn f<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
let mut x = foo::<&'a ()>; //~ ERROR: lifetime may not live long enough
x = foo::<&'b ()>; //~ ERROR: lifetime may not live long enough
x = foo::<&'c ()>;
x(a);
x(b);
x(c);
}
fn g<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
let x = foo::<&'c ()>;
let _: &'c () = x(a); //~ ERROR lifetime may not live long enough
}
fn h<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
let x = foo::<&'a ()>;
let _: &'a () = x(c);
}
fn i<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
let mut x = foo::<&'c ()>;
x = foo::<&'b ()>; //~ ERROR lifetime may not live long enough
x = foo::<&'a ()>; //~ ERROR lifetime may not live long enough
x(a);
x(b);
x(c);
}
fn j<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
let x = match true {
true => foo::<&'b ()>, //~ ERROR lifetime may not live long enough
false => foo::<&'a ()>, //~ ERROR lifetime may not live long enough
};
x(a);
x(b);
x(c);
}
fn k<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
let x = match true {
true => foo::<&'c ()>,
false => foo::<&'a ()>, //~ ERROR lifetime may not live long enough
};
x(a);
x(b); //~ ERROR lifetime may not live long enough
x(c);
}
fn main() {}