src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.rs

   1 #![feature(bindings_after_at)]
   2
   3 enum Option<T> {
   4     None,
   5     Some(T),
   6 }
   7
   8 fn main() {
   9     match &mut Some(1) {
  10         ref mut z @ &mut Some(ref a) => {
  11         //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  12         //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
  13             **z = None;
  14             println!("{}", *a);
  15         }
  16         _ => ()
  17     }
  18
  19     struct U;
  20
  21     // Prevent promotion:
  22     fn u() -> U { U }
  23
  24     fn f1(ref a @ ref mut b: U) {}
  25     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  26     fn f2(ref mut a @ ref b: U) {}
  27     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  28     fn f3(ref a @ [ref b, ref mut mid @ .., ref c]: [U; 4]) {}
  29     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  30     fn f4_also_moved(ref a @ ref mut b @ c: U) {}
  31     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  32     //~| ERROR cannot move out of value because it is borrowed
  33     //~| ERROR borrow of moved value
  34
  35     let ref mut a @ (ref b @ ref mut c) = u(); // sub-in-sub
  36     //~^ ERROR cannot borrow value as mutable more than once at a time
  37     //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
  38
  39     let ref a @ ref mut b = U;
  40     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  41     let ref mut a @ ref b = U;
  42     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  43     let ref a @ (ref mut b, ref mut c) = (U, U);
  44     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  45     let ref mut a @ (ref b, ref c) = (U, U);
  46     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  47
  48     let ref mut a @ ref b = u();
  49     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  50     //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
  51     *a = u();
  52     drop(b);
  53     let ref a @ ref mut b = u();
  54     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  55     //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
  56     *b = u();
  57     drop(a);
  58
  59     let ref mut a @ ref b = U;
  60     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  61     *a = U;
  62     drop(b);
  63     let ref a @ ref mut b = U;
  64     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  65     *b = U;
  66     drop(a);
  67
  68     match Ok(U) {
  69         ref mut a @ Ok(ref b) | ref mut a @ Err(ref b) => {
  70             //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  71             //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
  72             *a = Err(U);
  73             drop(b);
  74         }
  75     }
  76
  77     match Ok(U) {
  78         ref a @ Ok(ref mut b) | ref a @ Err(ref mut b) => {
  79             //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  80             //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
  81             //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
  82             //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
  83             *b = U;
  84             drop(a);
  85         }
  86     }
  87
  88     match Ok(U) {
  89         ref a @ Ok(ref mut b) | ref a @ Err(ref mut b) if { *b = U; false } => {}
  90         //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
  91         //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
  92         //~| ERROR cannot assign to `*b`, as it is immutable for the pattern guard
  93         _ => {}
  94     }
  95     match Ok(U) {
  96         ref mut a @ Ok(ref b) | ref mut a @ Err(ref b) if { *a = Err(U); false } => {}
  97         //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
  98         //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
  99         //~| ERROR cannot assign to `*a`, as it is immutable for the pattern guard
 100         _ => {}
 101     }
 102     match Ok(U) {
 103         ref a @ Ok(ref mut b) | ref a @ Err(ref mut b) if { drop(b); false } => {}
 104         //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
 105         //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
 106         //~| ERROR cannot move out of `b` in pattern guard
 107         //~| ERROR cannot move out of `b` in pattern guard
 108         _ => {}
 109     }
 110     match Ok(U) {
 111         ref mut a @ Ok(ref b) | ref mut a @ Err(ref b) if { drop(a); false } => {}
 112         //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
 113         //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
 114         //~| ERROR cannot move out of `a` in pattern guard
 115         //~| ERROR cannot move out of `a` in pattern guard
 116         _ => {}
 117     }
 118
 119     let ref a @ (ref mut b, ref mut c) = (U, U);
 120     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
 121     //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
 122     *b = U;
 123     *c = U;
 124
 125     let ref a @ (ref mut b, ref mut c) = (U, U);
 126     //~^ ERROR cannot borrow value as mutable because it is also borrowed as immutable
 127     //~| ERROR cannot borrow value as immutable because it is also borrowed as mutable
 128     *b = U;
 129     drop(a);
 130
 131     let ref a @ (ref mut b, ref mut c) = (U, U);
 132     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
 133     *b = U; //~| ERROR cannot borrow value as mutable because it is also borrowed as immutable
 134     *c = U;
 135     drop(a);
 136     let ref mut a @ (ref b, ref c) = (U, U);
 137     //~^ ERROR cannot borrow value as immutable because it is also borrowed as mutable
 138 }