- // MIR for `main` before CopyProp
+ // MIR for `main` after CopyProp
  
  fn main() -> () {
      let mut _0: ();
      let mut _1: i32;
      let mut _3: std::ops::Range<usize>;
      let mut _4: std::ops::Range<usize>;
      let mut _5: usize;
      let mut _6: &[i32];
      let mut _7: &[i32; 4];
      let mut _9: ();
      let _10: ();
      let mut _11: std::option::Option<usize>;
      let mut _12: &mut std::ops::Range<usize>;
      let mut _13: &mut std::ops::Range<usize>;
      let mut _14: isize;
      let mut _15: !;
      let mut _17: i32;
      let _18: usize;
      let mut _19: usize;
      let mut _20: bool;
      scope 1 {
          debug sum => _1;
          let _2: [i32; 4];
          scope 2 {
              debug a => _2;
              let mut _8: std::ops::Range<usize>;
              scope 3 {
                  debug iter => _8;
                  let _16: usize;
                  scope 4 {
                      debug i => _16;
                  }
              }
          }
      }
  
      bb0: {
          StorageLive(_1);
          _1 = const 0_i32;
          StorageLive(_2);
          _2 = [const 0_i32, const 10_i32, const 20_i32, const 30_i32];
          StorageLive(_3);
          StorageLive(_4);
          StorageLive(_5);
          StorageLive(_6);
          StorageLive(_7);
          _7 = &_2;
          _6 = move _7 as &[i32] (PointerCoercion(Unsize, Implicit));
          StorageDead(_7);
          _5 = core::slice::<impl [i32]>::len(move _6) -> [return: bb1, unwind continue];
      }
  
      bb1: {
          StorageDead(_6);
          _4 = std::ops::Range::<usize> { start: const 0_usize, end: move _5 };
          StorageDead(_5);
          _3 = <std::ops::Range<usize> as IntoIterator>::into_iter(move _4) -> [return: bb2, unwind continue];
      }
  
      bb2: {
          StorageDead(_4);
          StorageLive(_8);
          _8 = move _3;
          goto -> bb3;
      }
  
      bb3: {
-         StorageLive(_10);
          StorageLive(_11);
          StorageLive(_12);
          StorageLive(_13);
          _13 = &mut _8;
          _12 = &mut (*_13);
          _11 = <std::ops::Range<usize> as Iterator>::next(move _12) -> [return: bb4, unwind continue];
      }
  
      bb4: {
          StorageDead(_12);
          _14 = discriminant(_11);
          switchInt(move _14) -> [0: bb7, 1: bb6, otherwise: bb5];
      }
  
      bb5: {
          unreachable;
      }
  
      bb6: {
-         StorageLive(_16);
          _16 = copy ((_11 as Some).0: usize);
          StorageLive(_17);
-         StorageLive(_18);
-         _18 = copy _16;
          _19 = Len(_2);
-         _20 = Lt(copy _18, copy _19);
-         assert(move _20, "index out of bounds: the length is {} but the index is {}", move _19, copy _18) -> [success: bb8, unwind continue];
+         _20 = Lt(copy _16, copy _19);
+         assert(move _20, "index out of bounds: the length is {} but the index is {}", move _19, copy _16) -> [success: bb8, unwind continue];
      }
  
      bb7: {
          _0 = const ();
          StorageDead(_13);
          StorageDead(_11);
-         StorageDead(_10);
          StorageDead(_8);
          StorageDead(_3);
          StorageDead(_2);
          StorageDead(_1);
          return;
      }
  
      bb8: {
-         _17 = copy _2[_18];
+         _17 = copy _2[_16];
          _1 = Add(copy _1, move _17);
          StorageDead(_17);
-         StorageDead(_18);
-         _10 = const ();
-         StorageDead(_16);
          StorageDead(_13);
          StorageDead(_11);
-         StorageDead(_10);
-         _9 = const ();
          goto -> bb3;
      }
  }