src/test/ui/wf/wf-static-method.rs

   1 // check that static methods don't get to assume their trait-ref
   2 // is well-formed.
   3 // FIXME(#27579): this is just a bug. However, our checking with
   4 // static inherent methods isn't quite working - need to
   5 // fix that before removing the check.
   6
   7 // revisions: base nll
   8 // ignore-compare-mode-nll
   9 //[nll] compile-flags: -Z borrowck=mir
  10
  11 trait Foo<'a, 'b, T>: Sized {
  12     fn make_me() -> Self { loop {} }
  13     fn static_evil(u: &'b u32) -> &'a u32;
  14 }
  15
  16 struct Evil<'a, 'b: 'a>(Option<&'a &'b ()>);
  17
  18 impl<'a, 'b> Foo<'a, 'b, Evil<'a, 'b>> for () {
  19     fn make_me() -> Self { }
  20     fn static_evil(u: &'b u32) -> &'a u32 {
  21         u
  22         //[base]~^ ERROR E0312
  23         //[nll]~^^ ERROR lifetime may not live long enough
  24     }
  25 }
  26
  27 struct IndirectEvil<'a, 'b: 'a>(Option<&'a &'b ()>);
  28
  29 impl<'a, 'b> Foo<'a, 'b, ()> for IndirectEvil<'a, 'b> {
  30     fn make_me() -> Self { IndirectEvil(None) }
  31     fn static_evil(u: &'b u32) -> &'a u32 {
  32         let me = Self::make_me();
  33         //[base]~^ ERROR lifetime bound not satisfied
  34         //[nll]~^^ ERROR lifetime may not live long enough
  35         loop {} // (`me` could be used for the lifetime transmute).
  36     }
  37 }
  38
  39 impl<'a, 'b> Evil<'a, 'b> {
  40     fn inherent_evil(u: &'b u32) -> &'a u32 {
  41         u
  42         //[base]~^ ERROR E0312
  43         //[nll]~^^ ERROR lifetime may not live long enough
  44     }
  45 }
  46
  47 // while static methods don't get to *assume* this, we still
  48 // *check* that they hold.
  49
  50 fn evil<'a, 'b>(b: &'b u32) -> &'a u32 {
  51     <()>::static_evil(b)
  52     //[base]~^ ERROR cannot infer an appropriate lifetime
  53     //[nll]~^^ ERROR lifetime may not live long enough
  54 }
  55
  56 fn indirect_evil<'a, 'b>(b: &'b u32) -> &'a u32 {
  57     <IndirectEvil>::static_evil(b)
  58     //[base]~^ ERROR cannot infer an appropriate lifetime
  59     //[nll]~^^ ERROR lifetime may not live long enough
  60 }
  61
  62 fn inherent_evil<'a, 'b>(b: &'b u32) -> &'a u32 {
  63     <Evil>::inherent_evil(b)
  64     //[base]~^ ERROR cannot infer an appropriate lifetime
  65     //[nll]~^^ ERROR lifetime may not live long enough
  66 }
  67
  68
  69 fn main() {}