rust/src/test/ui/rfc1623.rs
Matthew Jasper 94c11dfe78 Report "nice" placeholder errors more often
If we have a cause containing `ValuePairs::PolyTraitRefs` but neither
TraitRef has any escaping bound regions then we report the same error as
for `ValuePairs::TraitRefs`.
2021-02-09 22:59:32 +00:00

93 lines
2.8 KiB
Rust

#![allow(dead_code)]
fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
a
}
// The incorrect case without `for<'a>` is tested for in `rfc1623-2.rs`
static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
&(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
struct SomeStruct<'x, 'y, 'z: 'x> {
foo: &'x Foo<'z>,
bar: &'x Bar<'z>,
f: &'y dyn for<'a, 'b> Fn(&'a Foo<'b>) -> &'a Foo<'b>,
}
fn id<T>(t: T) -> T {
t
}
static SOME_STRUCT: &SomeStruct = &SomeStruct {
foo: &Foo { bools: &[false, true] },
bar: &Bar { bools: &[true, true] },
f: &id,
//~^ ERROR implementation of `FnOnce` is not general enough
};
// very simple test for a 'static static with default lifetime
static STATIC_STR: &'static str = "&'static str";
const CONST_STR: &'static str = "&'static str";
// this should be the same as without default:
static EXPLICIT_STATIC_STR: &'static str = "&'static str";
const EXPLICIT_CONST_STR: &'static str = "&'static str";
// a function that elides to an unbound lifetime for both in- and output
fn id_u8_slice(arg: &[u8]) -> &[u8] {
arg
}
// one with a function, argument elided
static STATIC_SIMPLE_FN: &'static fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
const CONST_SIMPLE_FN: &'static fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
// this should be the same as without elision
static STATIC_NON_ELIDED_fN: &'static for<'a> fn(&'a [u8]) -> &'a [u8] =
&(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
const CONST_NON_ELIDED_fN: &'static for<'a> fn(&'a [u8]) -> &'a [u8] =
&(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
// another function that elides, each to a different unbound lifetime
fn multi_args(a: &u8, b: &u8, c: &u8) {}
static STATIC_MULTI_FN: &'static fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
const CONST_MULTI_FN: &'static fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
struct Foo<'a> {
bools: &'a [bool],
}
static STATIC_FOO: Foo<'static> = Foo { bools: &[true, false] };
const CONST_FOO: Foo<'static> = Foo { bools: &[true, false] };
type Bar<'a> = Foo<'a>;
static STATIC_BAR: Bar<'static> = Bar { bools: &[true, false] };
const CONST_BAR: Bar<'static> = Bar { bools: &[true, false] };
type Baz<'a> = fn(&'a [u8]) -> Option<u8>;
fn baz(e: &[u8]) -> Option<u8> {
e.first().map(|x| *x)
}
static STATIC_BAZ: &'static Baz<'static> = &(baz as Baz);
const CONST_BAZ: &'static Baz<'static> = &(baz as Baz);
static BYTES: &'static [u8] = &[1, 2, 3];
fn main() {
let x = &[1u8, 2, 3];
let y = x;
// this works, so lifetime < `'static` is valid
assert_eq!(Some(1), STATIC_BAZ(y));
assert_eq!(Some(1), CONST_BAZ(y));
let y = &[1u8, 2, 3];
STATIC_BAZ(BYTES); // BYTES has static lifetime
CONST_BAZ(y); // interestingly this does not get reported
}