1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
17 fn any_lifetime<'a>() -> &'a u32 { &5 }
19 fn static_lifetime() -> &'static u32 { &5 }
21 fn any_lifetime_as_static_impl_trait() -> impl Debug {
25 fn lifetimes_as_static_impl_trait() -> impl Debug {
29 fn no_params_or_lifetimes_is_static() -> impl Debug + 'static {
30 lifetimes_as_static_impl_trait()
33 fn static_input_type_is_static<T: Debug + 'static>(x: T) -> impl Debug + 'static { x }
35 fn type_outlives_reference_lifetime<'a, T: Debug>(x: &'a T) -> impl Debug + 'a { x }
36 fn type_outlives_reference_lifetime_elided<T: Debug>(x: &T) -> impl Debug + '_ { x }
38 trait SingleRegionTrait<'a> {}
39 impl<'a> SingleRegionTrait<'a> for u32 {}
40 impl<'a> SingleRegionTrait<'a> for &'a u32 {}
41 struct SingleRegionStruct<'a>(&'a u32);
43 fn simple_type_hrtb<'b>() -> impl for<'a> SingleRegionTrait<'a> { 5 }
44 // FIXME(cramertj) add test after #45992 lands to ensure lint is triggered
45 fn elision_single_region_trait(x: &u32) -> impl SingleRegionTrait { x }
46 fn elision_single_region_struct(x: SingleRegionStruct) -> impl Into<SingleRegionStruct> { x }
48 fn closure_hrtb() -> impl for<'a> Fn(&'a u32) { |_| () }
49 fn closure_hr_elided() -> impl Fn(&u32) { |_| () }
50 fn closure_hr_elided_return() -> impl Fn(&u32) -> &u32 { |x| x }
51 fn closure_pass_through_elided_return(x: impl Fn(&u32) -> &u32) -> impl Fn(&u32) -> &u32 { x }
52 fn closure_pass_through_reference_elided(x: &impl Fn(&u32) -> &u32) -> &impl Fn(&u32) -> &u32 { x }
54 fn nested_lifetime<'a>(input: &'a str)
55 -> impl Iterator<Item = impl Iterator<Item = i32> + 'a> + 'a
57 input.lines().map(|line| {
58 line.split_whitespace().map(|cell| cell.parse().unwrap())
62 fn pass_through_elision(x: &u32) -> impl Into<&u32> { x }
63 fn pass_through_elision_with_fn_ptr(x: &fn(&u32) -> &u32) -> impl Into<&fn(&u32) -> &u32> { x }
65 fn pass_through_elision_with_fn_path<T: Fn(&u32) -> &u32>(
67 ) -> &impl Fn(&u32) -> &u32 { x }
69 fn foo(x: &impl Debug) -> &impl Debug { x }
70 fn foo_explicit_lifetime<'a>(x: &'a impl Debug) -> &'a impl Debug { x }
71 fn foo_explicit_arg<T: Debug>(x: &T) -> &impl Debug { x }
73 fn mixed_lifetimes<'a>() -> impl for<'b> Fn(&'b &'a u32) { |_| () }
74 fn mixed_as_static() -> impl Fn(&'static &'static u32) { mixed_lifetimes() }
76 trait MultiRegionTrait<'a, 'b>: Debug {}
79 struct MultiRegionStruct<'a, 'b>(&'a u32, &'b u32);
80 impl<'a, 'b> MultiRegionTrait<'a, 'b> for MultiRegionStruct<'a, 'b> {}
83 struct NoRegionStruct;
84 impl<'a, 'b> MultiRegionTrait<'a, 'b> for NoRegionStruct {}
86 fn finds_least_region<'a: 'b, 'b>(x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> {
87 MultiRegionStruct(x, y)
90 fn finds_explicit_bound<'a: 'b, 'b>
91 (x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> + 'b
93 MultiRegionStruct(x, y)
96 fn finds_explicit_bound_even_without_least_region<'a, 'b>
97 (x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> + 'b
102 /* FIXME: `impl Trait<'a> + 'b` should live as long as 'b, even if 'b outlives 'a
103 fn outlives_bounds_even_with_contained_regions<'a, 'b>
104 (x: &'a u32, y: &'b u32) -> impl Debug + 'b
106 finds_explicit_bound_even_without_least_region(x, y)
110 fn unnamed_lifetimes_arent_contained_in_impl_trait_and_will_unify<'a, 'b>
111 (x: &'a u32, y: &'b u32) -> impl Debug
113 fn deref<'lt>(x: &'lt u32) -> impl Debug { *x }
115 if true { deref(x) } else { deref(y) }
118 fn can_add_region_bound_to_static_type<'a, 'b>(_: &'a u32) -> impl Debug + 'a { 5 }
120 struct MyVec(Vec<Vec<u8>>);
122 impl<'unnecessary_lifetime> MyVec {
123 fn iter_doesnt_capture_unnecessary_lifetime<'s>(&'s self) -> impl Iterator<Item = &'s u8> {
124 self.0.iter().flat_map(|inner_vec| inner_vec.iter())