This test is new as of CL 355495 (CC @mou-hao, @alexbrainman, @odeke-em)

As far as I can tell this is a bug in the test, but it is a release blocker for Go 1.18 via #11811.
(This looks like a good use-case for the new unsafe.Slice!)

I can fix that.

(This looks like a good use-case for the new unsafe.Slice!)

Though it's better to migrate to unsafe.Slice, but I don't think using unsafe.Slice will help in this case. unsafe.Slice only checks for overflow, while the problem here is the underlying array straddle multiple heap objects.

The problem code:

copy((*[1 << 29]uint16)(unsafe.Pointer(&typedBufferPtr.FileName[0]))[:], newNameUTF16)

We need to change it to [:n:n] (where n is len(newNameUTF16)) instead of [:], so the compiler can recognize the pattern and make an exception.

Change https://golang.org/cl/359496 mentions this issue: windows: fix test causing checkptr failure

We need to change it to [:n:n] (where n is len(newNameUTF16)) instead of [:], so the compiler can recognize the pattern and make an exception.

Indeed. My fault for forgetting it.

Alex