src/test/ui/nll/polonius-smoke-test.rs

   1 // Check that Polonius borrow check works for simple cases.
   2 // ignore-compare-mode-nll
   3 // compile-flags: -Z borrowck=mir -Zpolonius
   4
   5 pub fn return_ref_to_local() -> &'static i32 {
   6     let x = 0;
   7     &x //~ ERROR
   8 }
   9
  10 pub fn use_while_mut() {
  11     let mut x = 0;
  12     let y = &mut x;
  13     let z = x; //~ ERROR
  14     let w = y;
  15 }
  16
  17 pub fn use_while_mut_fr(x: &mut i32) -> &mut i32 {
  18     let y = &mut *x;
  19     let z = x; //~ ERROR
  20     y
  21 }
  22
  23 // Cases like this are why we have Polonius.
  24 pub fn position_dependent_outlives(x: &mut i32, cond: bool) -> &mut i32 {
  25     let y = &mut *x;
  26     if cond {
  27         return y;
  28     } else {
  29         *x = 0;
  30         return x;
  31     }
  32 }
  33
  34 fn foo<'a, 'b>(p: &'b &'a mut usize) -> &'b usize {
  35     p
  36 }
  37
  38 // Check that we create constraints for well-formedness of function arguments
  39 fn well_formed_function_inputs() {
  40     let s = &mut 1;
  41     let r = &mut *s;
  42     let tmp = foo(&r);
  43     s; //~ ERROR
  44     tmp;
  45 }
  46
  47 fn main() {}