- // MIR for `main` before Derefer
+ // MIR for `main` after Derefer
  
  fn main() -> () {
      let mut _0: ();                      // return place in scope 0 at $DIR/derefer_test.rs:+0:11: +0:11
      let mut _1: (i32, i32);              // in scope 0 at $DIR/derefer_test.rs:+1:9: +1:14
      let mut _3: &mut (i32, i32);         // in scope 0 at $DIR/derefer_test.rs:+2:22: +2:28
+     let mut _6: &mut (i32, i32);         // in scope 0 at $DIR/derefer_test.rs:+2:9: +2:14
+     let mut _7: &mut (i32, i32);         // in scope 0 at $DIR/derefer_test.rs:+2:9: +2:14
      scope 1 {
          debug a => _1;                   // in scope 1 at $DIR/derefer_test.rs:+1:9: +1:14
          let mut _2: (i32, &mut (i32, i32)); // in scope 1 at $DIR/derefer_test.rs:+2:9: +2:14
          scope 2 {
              debug b => _2;               // in scope 2 at $DIR/derefer_test.rs:+2:9: +2:14
              let _4: &mut i32;            // in scope 2 at $DIR/derefer_test.rs:+3:9: +3:10
              scope 3 {
                  debug x => _4;           // in scope 3 at $DIR/derefer_test.rs:+3:9: +3:10
                  let _5: &mut i32;        // in scope 3 at $DIR/derefer_test.rs:+4:9: +4:10
                  scope 4 {
                      debug y => _5;       // in scope 4 at $DIR/derefer_test.rs:+4:9: +4:10
                  }
              }
          }
      }
  
      bb0: {
          StorageLive(_1);                 // scope 0 at $DIR/derefer_test.rs:+1:9: +1:14
          _1 = (const 42_i32, const 43_i32); // scope 0 at $DIR/derefer_test.rs:+1:17: +1:24
          StorageLive(_2);                 // scope 1 at $DIR/derefer_test.rs:+2:9: +2:14
          StorageLive(_3);                 // scope 1 at $DIR/derefer_test.rs:+2:22: +2:28
          _3 = &mut _1;                    // scope 1 at $DIR/derefer_test.rs:+2:22: +2:28
          _2 = (const 99_i32, move _3);    // scope 1 at $DIR/derefer_test.rs:+2:17: +2:29
          StorageDead(_3);                 // scope 1 at $DIR/derefer_test.rs:+2:28: +2:29
          StorageLive(_4);                 // scope 2 at $DIR/derefer_test.rs:+3:9: +3:10
-         _4 = &mut ((*(_2.1: &mut (i32, i32))).0: i32); // scope 2 at $DIR/derefer_test.rs:+3:13: +3:26
+         _6 = deref_copy (_2.1: &mut (i32, i32)); // scope 2 at $DIR/derefer_test.rs:+3:13: +3:26
+         _4 = &mut ((*_6).0: i32);        // scope 2 at $DIR/derefer_test.rs:+3:13: +3:26
          StorageLive(_5);                 // scope 3 at $DIR/derefer_test.rs:+4:9: +4:10
-         _5 = &mut ((*(_2.1: &mut (i32, i32))).1: i32); // scope 3 at $DIR/derefer_test.rs:+4:13: +4:26
+         _7 = deref_copy (_2.1: &mut (i32, i32)); // scope 3 at $DIR/derefer_test.rs:+4:13: +4:26
+         _5 = &mut ((*_7).1: i32);        // scope 3 at $DIR/derefer_test.rs:+4:13: +4:26
          _0 = const ();                   // scope 0 at $DIR/derefer_test.rs:+0:11: +5:2
          StorageDead(_5);                 // scope 3 at $DIR/derefer_test.rs:+5:1: +5:2
          StorageDead(_4);                 // scope 2 at $DIR/derefer_test.rs:+5:1: +5:2
          StorageDead(_2);                 // scope 1 at $DIR/derefer_test.rs:+5:1: +5:2
          StorageDead(_1);                 // scope 0 at $DIR/derefer_test.rs:+5:1: +5:2
          return;                          // scope 0 at $DIR/derefer_test.rs:+5:2: +5:2
      }
  }