Singularity/Library/PackageCache/com.unity.burst@1.8.4/Documentation~/aliasing-job-system.md

Aliasing and the job system

Unity's job system infrastructure has some limitations on what can alias within a job struct:

• Structs attributed with [NativeContainer] (for example, NativeArray and NativeSlice) that are members of a job struct don't alias.
• Job struct members with the [NativeDisableContainerSafetyRestriction] attribute can alias with other members. This is because this attribute explicitly opts in to this kind of aliasing.
• Pointers to structs attributed with [NativeContainer] can't appear in other structs attributed with [NativeContainer]. For example, you can't have a NativeArray<NativeSlice<T>>.

The following example job shows how these limitations work in practice:

[BurstCompile]
private struct MyJob : IJob
{
    public NativeArray<float> a;
    public NativeArray<float> b;
    public NativeSlice<int> c;

    [NativeDisableContainerSafetyRestriction]
    public NativeArray<byte> d;

    public void Execute() { ... }
}

• a, b, and c don't alias with each other.
• d can alias with a, b, or c.

Tip

If you're used to working with C/C++'s Type Based Alias Analysis (TBAA), then you might assume that because d has a different type from a, b, or c, it shouldn't alias. However, in C#, pointers don't have any assumptions that pointing to a different type results in no aliasing. This is why d is assumed to alias with a, b, or c.