| - // MIR for `main` before DataflowConstProp | 
 | + // MIR for `main` after DataflowConstProp | 
 |    | 
 |   fn main() -> () { | 
 |       let mut _0: (); | 
 |       let _1: A; | 
 |       let mut _2: std::boxed::Box<[bool]>; | 
 |       scope 1 { | 
 |           debug a => _1; | 
 |       } | 
 |       scope 2 (inlined <Box<[bool]> as Default>::default) { | 
 |           let _3: std::ptr::Unique<[bool]>; | 
 |           let mut _4: std::ptr::Unique<[bool; 0]>; | 
 |           scope 3 { | 
 |           } | 
 |           scope 4 (inlined Unique::<[bool; 0]>::dangling) { | 
 |               let mut _5: std::ptr::NonNull<[bool; 0]>; | 
 |               scope 5 (inlined NonNull::<[bool; 0]>::dangling) { | 
 |                   let mut _6: std::num::NonZero<usize>; | 
 |                   scope 6 { | 
 |                       scope 8 (inlined std::ptr::Alignment::as_nonzero) { | 
 |                       } | 
 |                       scope 9 (inlined NonNull::<[bool; 0]>::without_provenance) { | 
 |                           let _7: *const [bool; 0]; | 
 |                           scope 10 { | 
 |                           } | 
 |                           scope 11 (inlined NonZero::<usize>::get) { | 
 |                           } | 
 |                           scope 12 (inlined std::ptr::without_provenance::<[bool; 0]>) { | 
 |                               scope 13 (inlined without_provenance_mut::<[bool; 0]>) { | 
 |                               } | 
 |                           } | 
 |                       } | 
 |                   } | 
 |                   scope 7 (inlined std::ptr::Alignment::of::<[bool; 0]>) { | 
 |                   } | 
 |               } | 
 |           } | 
 |       } | 
 |    | 
 |       bb0: { | 
 |           StorageLive(_1); | 
 |           StorageLive(_2); | 
 |           StorageLive(_3); | 
 |           StorageLive(_4); | 
 |           StorageLive(_5); | 
 |           StorageLive(_6); | 
 |           _6 = const NonZero::<usize>(core::num::niche_types::NonZeroUsizeInner(1_usize)); | 
 |           StorageLive(_7); | 
 |           _7 = const {0x1 as *const [bool; 0]}; | 
 |           _5 = const NonNull::<[bool; 0]> {{ pointer: {0x1 as *const [bool; 0]} }}; | 
 |           StorageDead(_7); | 
 |           StorageDead(_6); | 
 |           _4 = const Unique::<[bool; 0]> {{ pointer: NonNull::<[bool; 0]> {{ pointer: {0x1 as *const [bool; 0]} }}, _marker: PhantomData::<[bool; 0]> }}; | 
 |           StorageDead(_5); | 
 |           _3 = const Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC0, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }}; | 
 |           StorageDead(_4); | 
 |           _2 = const Box::<[bool]>(Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC1, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }}, std::alloc::Global); | 
 |           StorageDead(_3); | 
 |           _1 = const A {{ foo: Box::<[bool]>(Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC2, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }}, std::alloc::Global) }}; | 
 |           StorageDead(_2); | 
 |           _0 = const (); | 
 |           drop(_1) -> [return: bb1, unwind: bb2]; | 
 |       } | 
 |    | 
 |       bb1: { | 
 |           StorageDead(_1); | 
 |           return; | 
 |       } | 
 |    | 
 |       bb2 (cleanup): { | 
 |           resume; | 
 |       } | 
 |   } | 
 |    | 
 |   ALLOC2 (size: 8, align: 4) { .. } | 
 |    | 
 |   ALLOC1 (size: 8, align: 4) { .. } | 
 |    | 
 |   ALLOC0 (size: 8, align: 4) { .. } | 
 |    |