src/test/ui/rfc1623.rs

   1 #![allow(dead_code)]
   2
   3 fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
   4     a
   5 }
   6
   7 // The incorrect case without `for<'a>` is tested for in `rfc1623-2.rs`
   8 static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
   9     &(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
  10
  11 struct SomeStruct<'x, 'y, 'z: 'x> {
  12     foo: &'x Foo<'z>,
  13     bar: &'x Bar<'z>,
  14     f: &'y dyn for<'a, 'b> Fn(&'a Foo<'b>) -> &'a Foo<'b>,
  15 }
  16
  17 // Without this, the wf-check will fail early so we'll never see the
  18 // error in SOME_STRUCT's body.
  19 unsafe impl<'x, 'y, 'z: 'x> Sync for SomeStruct<'x, 'y, 'z> {}
  20
  21 fn id<T>(t: T) -> T {
  22     t
  23 }
  24
  25 static SOME_STRUCT: &SomeStruct = &SomeStruct {
  26     foo: &Foo { bools: &[false, true] },
  27     bar: &Bar { bools: &[true, true] },
  28     f: &id,
  29     //~^ ERROR implementation of `FnOnce` is not general enough
  30 };
  31
  32 // very simple test for a 'static static with default lifetime
  33 static STATIC_STR: &'static str = "&'static str";
  34 const CONST_STR: &'static str = "&'static str";
  35
  36 // this should be the same as without default:
  37 static EXPLICIT_STATIC_STR: &'static str = "&'static str";
  38 const EXPLICIT_CONST_STR: &'static str = "&'static str";
  39
  40 // a function that elides to an unbound lifetime for both in- and output
  41 fn id_u8_slice(arg: &[u8]) -> &[u8] {
  42     arg
  43 }
  44
  45 // one with a function, argument elided
  46 static STATIC_SIMPLE_FN: &'static fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
  47 const CONST_SIMPLE_FN: &'static fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
  48
  49 // this should be the same as without elision
  50 static STATIC_NON_ELIDED_fN: &'static for<'a> fn(&'a [u8]) -> &'a [u8] =
  51     &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
  52 const CONST_NON_ELIDED_fN: &'static for<'a> fn(&'a [u8]) -> &'a [u8] =
  53     &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
  54
  55 // another function that elides, each to a different unbound lifetime
  56 fn multi_args(a: &u8, b: &u8, c: &u8) {}
  57
  58 static STATIC_MULTI_FN: &'static fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
  59 const CONST_MULTI_FN: &'static fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
  60
  61 struct Foo<'a> {
  62     bools: &'a [bool],
  63 }
  64
  65 static STATIC_FOO: Foo<'static> = Foo { bools: &[true, false] };
  66 const CONST_FOO: Foo<'static> = Foo { bools: &[true, false] };
  67
  68 type Bar<'a> = Foo<'a>;
  69
  70 static STATIC_BAR: Bar<'static> = Bar { bools: &[true, false] };
  71 const CONST_BAR: Bar<'static> = Bar { bools: &[true, false] };
  72
  73 type Baz<'a> = fn(&'a [u8]) -> Option<u8>;
  74
  75 fn baz(e: &[u8]) -> Option<u8> {
  76     e.first().map(|x| *x)
  77 }
  78
  79 static STATIC_BAZ: &'static Baz<'static> = &(baz as Baz);
  80 const CONST_BAZ: &'static Baz<'static> = &(baz as Baz);
  81
  82 static BYTES: &'static [u8] = &[1, 2, 3];
  83
  84 fn main() {
  85     let x = &[1u8, 2, 3];
  86     let y = x;
  87
  88     // this works, so lifetime < `'static` is valid
  89     assert_eq!(Some(1), STATIC_BAZ(y));
  90     assert_eq!(Some(1), CONST_BAZ(y));
  91
  92     let y = &[1u8, 2, 3];
  93
  94     STATIC_BAZ(BYTES); // BYTES has static lifetime
  95     CONST_BAZ(y); // interestingly this does not get reported
  96 }