src/test/ui/borrowck/borrowck-lend-flow.rs

   1 // Note: the borrowck analysis is currently flow-insensitive.
   2 // Therefore, some of these errors are marked as spurious and could be
   3 // corrected by a simple change to the analysis.  The others are
   4 // either genuine or would require more advanced changes.  The latter
   5 // cases are noted.
   6
   7 #![feature(box_syntax)]
   8
   9 fn borrow(_v: &isize) {}
  10 fn borrow_mut(_v: &mut isize) {}
  11 fn cond() -> bool { panic!() }
  12 fn for_func<F>(_f: F) where F: FnOnce() -> bool { panic!() }
  13 fn produce<T>() -> T { panic!(); }
  14
  15 fn inc(v: &mut Box<isize>) {
  16     *v = box (**v + 1);
  17 }
  18
  19 fn pre_freeze() {
  20     // In this instance, the freeze starts before the mut borrow.
  21
  22     let mut v: Box<_> = box 3;
  23     let _w = &v;
  24     borrow_mut(&mut *v); //~ ERROR cannot borrow
  25     _w.use_ref();
  26 }
  27
  28 fn post_freeze() {
  29     // In this instance, the const alias starts after the borrow.
  30
  31     let mut v: Box<_> = box 3;
  32     borrow_mut(&mut *v);
  33     let _w = &v;
  34 }
  35
  36 fn main() {}
  37
  38 trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { }  }
  39 impl<T> Fake for T { }