src/test/ui/borrowck/borrowck-mutate-in-guard.rs

   1 enum Enum<'a> {
   2     A(&'a isize),
   3     B(bool),
   4 }
   5
   6 fn foo() -> isize {
   7     let mut n = 42;
   8     let mut x = Enum::A(&mut n);
   9     match x {
  10         Enum::A(_) if { x = Enum::B(false); false } => 1,
  11         //~^ ERROR cannot assign in a pattern guard
  12         //~| ERROR cannot assign `x` in match guard
  13         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
  14         //~^ ERROR cannot mutably borrow in a pattern guard
  15         //~| ERROR cannot assign in a pattern guard
  16         //~| ERROR cannot mutably borrow `x` in match guard
  17         Enum::A(p) => *p,
  18         Enum::B(_) => 2,
  19     }
  20 }
  21
  22 fn main() {
  23     foo();
  24 }