tests/mir-opt/derefer_test.main.Derefer.diff

- // MIR for `main` before Derefer
+ // MIR for `main` after Derefer
  
  fn main() -> () {
      let mut _0: ();
      let mut _1: (i32, i32);
      let mut _3: &mut (i32, i32);
+     let mut _6: &mut (i32, i32);
+     let mut _7: &mut (i32, i32);
      scope 1 {
          debug a => _1;
          let mut _2: (i32, &mut (i32, i32));
          scope 2 {
              debug b => _2;
              let _4: &mut i32;
              scope 3 {
                  debug x => _4;
                  let _5: &mut i32;
                  scope 4 {
                      debug y => _5;
                  }
              }
          }
      }
  
      bb0: {
          StorageLive(_1);
          _1 = (const 42_i32, const 43_i32);
          StorageLive(_2);
          StorageLive(_3);
          _3 = &mut _1;
          _2 = (const 99_i32, move _3);
          StorageDead(_3);
          StorageLive(_4);
-         _4 = &mut ((*(_2.1: &mut (i32, i32))).0: i32);
+         _6 = deref_copy (_2.1: &mut (i32, i32));
+         _4 = &mut ((*_6).0: i32);
          StorageLive(_5);
-         _5 = &mut ((*(_2.1: &mut (i32, i32))).1: i32);
+         _7 = deref_copy (_2.1: &mut (i32, i32));
+         _5 = &mut ((*_7).1: i32);
          _0 = const ();
          StorageDead(_5);
          StorageDead(_4);
          StorageDead(_2);
          StorageDead(_1);
          return;
      }
  }