src/test/ui/nll/issue-54556-wrap-it-up.rs

   1 // This is testing how the diagnostic from issue #54556 behaves when
   2 // the destructor code is attached to a place held in a field of the
   3 // temporary being dropped.
   4 //
   5 // Eventually it would be nice if the diagnostic would actually report
   6 // that specific place and its type that implements the `Drop` trait.
   7 // But for the short term, it is acceptable to just print out the
   8 // whole type of the temporary.
   9
  10 #![allow(warnings)]
  11
  12 struct Wrap<'p> { p: &'p mut i32 }
  13
  14 impl<'p> Drop for Wrap<'p> {
  15     fn drop(&mut self) {
  16         *self.p += 1;
  17     }
  18 }
  19
  20 struct Foo<'p> { a: String, b: Wrap<'p> }
  21
  22 fn main() {
  23     let mut x = 0;
  24     let wrap = Wrap { p: &mut x };
  25     let s = String::from("str");
  26     let foo = Foo { a: s, b: wrap };
  27     x = 1; //~ ERROR cannot assign to `x` because it is borrowed [E0506]
  28 }