tests/ui/typeck/issue-18937.rs

   1 // Regression test for #18937.
   2
   3 use std::fmt;
   4
   5 #[derive(Debug)]
   6 struct MyString<'a>(&'a String);
   7
   8 struct B {
   9     list: Vec<Box<dyn fmt::Debug>>,
  10 }
  11
  12 trait A<'a> {
  13     fn foo<F>(&mut self, f: F)
  14         where F: fmt::Debug + 'a,
  15               Self: Sized;
  16 }
  17
  18 impl<'a> A<'a> for B {
  19     fn foo<F>(&mut self, f: F)
  20         where F: fmt::Debug + 'static, //~ ERROR impl has stricter
  21     {
  22         self.list.push(Box::new(f));
  23     }
  24 }
  25
  26 fn main() {
  27     let mut b = B { list: Vec::new() };
  28
  29     // Create a borrowed pointer, put it in `b`, then drop what's borrowing it
  30     let a = "hello".to_string();
  31     b.foo(MyString(&a));
  32
  33     // Drop the data which `b` has a reference to
  34     drop(a);
  35
  36     // Use the data, probably segfaulting
  37     for b in b.list.iter() {
  38         println!("{:?}", b);
  39     }
  40 }