loopdydoo.mir

// MIR for `loopdydoo`
// source = MirSource { instance: Item(DefId(0:20 ~ polonius_imprecision[317d]::loopdydoo[0])), promoted: None }
// pass_name = nll
// disambiguator = 0

| Free Region Mapping
| '_#0r | Global | ['_#0r, '_#1r]
| '_#1r | Local | ['_#1r]
|
| Inferred Region Values
| '_#0r | U0 | r3 | {bb0[0..=5], bb1[0], bb2[0], bb3[0..=3], bb4[0..=5], '_#0r, '_#1r}
| '_#1r | U0 | r4 | {bb0[0..=5], bb1[0], bb2[0], bb3[0..=3], bb4[0..=5], '_#1r}
| '_#2r | U0 | r0 | {bb0[3..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#3r | U0 | r1 | {bb0[4..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#4r | U0 | r2 | {bb0[4..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#5r | U0 | r5 | {bb0[4..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#6r | U0 | r8 | {bb0[4..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#7r | U0 | r6 | {bb0[4..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#8r | U0 | r7 | {bb0[4..=5], bb2[0], bb3[0..=3], bb4[0..=5]}
|
| Inference Constraints
| '_#0r live at {bb0[0..=5], bb1[0], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#1r live at {bb0[0..=5], bb1[0], bb2[0], bb3[0..=3], bb4[0..=5]}
| '_#2r live at {bb0[3]}
| '_#3r live at {bb3[2]}
| '_#4r live at {bb4[2]}
| '_#5r live at {bb0[4..=5], bb2[0], bb3[0..=2], bb4[3..=5]}
| '_#6r live at {bb4[0..=2]}
| '_#7r live at {bb3[3]}
| '_#8r live at {bb3[3]}
| '_#2r: '_#5r (r0: r5), due to Assignment at Single(bb0[3])
| '_#3r: '_#7r (r1: r6), due to Boring at Single(bb3[2])
| '_#4r: '_#5r (r2: r5), due to Assignment at Single(bb4[2])
| '_#5r: '_#3r (r5: r1), due to Boring at Single(bb3[2])
| '_#6r: '_#4r (r8: r2), due to Boring at Single(bb4[2])
| '_#7r: '_#8r (r6: r7), due to CallArgument at Single(bb3[3])
| '_#8r: '_#6r (r7: r8), due to Assignment at Single(bb3[3])
|
fn  loopdydoo() -> () {
    let mut _0: ();                      // return place
    let mut _1: &'_#5r mut Thing;        // "temp"
    let mut _2: Thing;                   
    let mut _3: !;                       
    let mut _4: ();                      
    let mut _6: &'_#7r mut Thing;        
    scope 1 {
        let _5: &'_#6r mut Thing;        // "v"
        scope 2 {
        }
    }

    bb0: {
        StorageLive(_1);                 // bb0[0]: p03-04
        StorageLive(_2);                 // bb0[1]: p05-06
        _2 = Thing;                      // bb0[2]: start p07: invalidates L0
                                         // bb0[2]: mid   p08: kill L0
        _1 = &'_#2r mut _2;              // bb0[3]: start p09: invalidates L0
                                         // bb0[3]: mid   p00: kill L1, borrow_region '2 L0
        FakeRead(ForLet, _1);            // bb0[4]: p10-11
        goto -> bb2;                     // bb0[5]: p12-13
    }

    bb1 (cleanup): {
        resume;                          // bb1[0]: p15-16 - p15: invalidates L0
    }

    bb2: {
        falseUnwind 
          -> [real: bb3, cleanup: bb1];  // bb2[0]: p14-17
    }

    bb3: {
        StorageLive(_5);                 // bb3[0]: p18-19
        StorageLive(_6);                 // bb3[1]: p20-21
        _6 = &'_#3r mut (*_1);           // bb3[2]: start p22: invalidates L1
                                         // bb3[2]: mid   p01: '5 requires L2 since p02, '5 flows into '7, '7 requires L2 (but '7 is not live) // borrow_region '3 L1
        _5 = const Thing::next(move _6)  // bb3[3]: start p23: invalidates L2, L2 borrow_live_at ('7 requires L2 since p01, but '7 is live here, therefore L2 is live) // ERROR 1
          -> [return: bb4, unwind: bb1]; // bb3[3]: mid   p24: '7r requires L2 since p01, '7 flows into '6, '6 requires L2 -- no killed facts here, but the call should kill L2 (this only fixes error #2 later)
    }

    bb4: {
        StorageDead(_6);                 // bb4[0]: p25-26
        FakeRead(ForLet, _5);            // bb4[1]: p27-28
        _1 = &'_#4r mut (*_5);           // bb4[2]: start p29: invalidates L2, L2 borrow_live_at, '6 requires L2 since p24 // ERROR 2 -- which disappears if we indeed kill L2 at mid bb3[3] (p24)
                                         // bb4[2]: mid   p02: borrow_region '4 L2, '4 requires L2, '4 flows into '5, '5 requires L2, kill L1
        _4 = ();                         // bb4[3]: p30-31
        StorageDead(_5);                 // bb4[4]: p32-33
        goto -> bb2;                     // bb4[5]: p34-35
    }
}