Bug Span.Slice not working in Bursted Job when safety checks is on

Burst 1.6.6
Unity 2021.3.4

So I have a job:

Code (CSharp):

1. [BurstCompile]
2.   public struct SDGridJob : IJobParallelFor {
3.     [ReadOnly] public NativeArray<float3> hexagons;
4.     [ReadOnly] public NativeArray<float3> positions;
5.     [ReadOnly] public NativeArray<float3> prevPositions;
6.  
7.     [WriteOnly] public NativeList<GridImpact>.ParallelWriter gridImpacts;
8.  
9.     public float outerRadius, innerRadius;
10.     public int2 gridSize;
11.     public float3 gridPosition;
12.  
13.     private const int searchRange = 1;
14.  
15.     public void Execute(int index) {
16.       var position = positions[index];
17.       var hashedPos = HC.CubeFromLocalPosition(position - gridPosition, outerRadius, innerRadius);
18.    
19.       Span<int3> neighbors = stackalloc int3[HC.HexagonsInRange(searchRange)];
20.       HC.GetSpiralHexagons(hashedPos, 1, neighbors);
21.       for(int i = 0; i < neighbors.Length; i++) {
22.         var neighbor = neighbors[i];
23.         var idx = HC.IndexFromCube(neighbor, gridSize);
24.         if(idx > 0 && idx < hexagons.Length) {
25.           var distance = math.sdHexPrism(hexagons[idx], new float2(outerRadius, 0), position);
26.           if(distance < 0) {
27.             gridImpacts.AddNoResize(new GridImpact {
28.               index = index,
29.               coords = neighbor,
30.               position = position + math.normalize(prevPositions[index] - position) * math.abs(distance)
31.             });
32.           }
33.         }
34.       }
35.     }
36.   }

Which fails in the function GetSpiralHexagons on hexagons.Slice

Code (CSharp):

1.     public static void GetSpiralHexagons(int3 center, int radius, Span<int3> hexagons) {
2.       hexagons[0] = center;
3.       for(int i = 1; i <= radius; i++) {
4.         var index = HexagonsInRange(i - 1);
5.         var slice = hexagons.Slice(index, HexagonsInRange(i) - index);
6.         GetRingHexagons(center, i, slice);
7.       }
8.     }

With the exception:

Code (CSharp):

1. System.ArgumentOutOfRangeException: start + length is less than zero or greater than Length..
2. This Exception was thrown from a job compiled with Burst, which has limited exception support.
3. 0x00007ff88f9f1bb7 (592d9ce4b8e13077f6d22783dbc5cc4) [HexCoordinates.cs:100] Model.HexCoordinates.GetSpiralHexagons
4. 0x00007ff88f9f13fb (592d9ce4b8e13077f6d22783dbc5cc4) [unknown:0] Unity.Jobs.IJobParallelForExtensions.ParallelForJobStruct`1<Model.SDGridJob>.Execute
5. 0x00007ff88f9f1011 (592d9ce4b8e13077f6d22783dbc5cc4) A2BB5B4F582043E0
6. 0x00007ff76b606cc0 (Unity) ExecuteJob
7. 0x00007ff76b606f75 (Unity) ExecuteJobCopyData
8. 0x00007ff76b607bcf (Unity) ForwardJobForEachToManaged
9. 0x00007ff76b60319c (Unity) JobQueue::Exec
10. 0x00007ff76b60345a (Unity) JobQueue::ExecuteJobFromHighPriorityStack
11. 0x00007ff76b6039e9 (Unity) JobQueue::ProcessJobs
12. 0x00007ff76b605a4f (Unity) JobQueue::WorkLoop
13. 0x00007ff76b7fdd07 (Unity) Thread::RunThreadWrapper
14. 0x00007ff8c81b7034 (KERNEL32) BaseThreadInitThunk
15. 0x00007ff8c9282651 (ntdll) RtlUserThreadStart
16.  

After that console is full of errors of unfreed ullocation, recompiling is not helping, only Unity restart solves it.
If I turn off collection checks or disable Burst - everything is working as expected. I've double checked Span.Slice receives correct values. Maybe I am missing something here?

 

The same behaviour for Burst 1.7.3

 

Hey, here is a HexagonsInRange method:

Code (CSharp):

1.     [MethodImpl(MethodImplOptions.AggressiveInlining)]
2.     public static int HexagonsInRange(int range) {
3.       return 1 + 3 * range * (range + 1);
4.     }

The values of start and length before exception:

index: 1, length 6

 

And the length of hexagons is 7

 

This is great, thank you!

 

Hey, will be this fix released for Burst 1.7.x or it will be done for 1.8.x only?

 

This is great, thank you!