Integer overflow in reverse! for an OffsetArray

[jishnub]

julia> v = [1:4;]
4-element Vector{Int64}:
 1
 2
 3
 4

julia> reverse!(v, firstindex(v))
4-element Vector{Int64}:
 4
 3
 2
 1

julia> vo = OffsetArray([1:4;], typemax(Int)-4)
4-element OffsetArray(::Vector{Int64}, 9223372036854775804:9223372036854775807) with eltype Int64 with indices 9223372036854775804:9223372036854775807:
 1
 2
 3
 4

julia> reverse!(vo, firstindex(vo))
4-element OffsetArray(::Vector{Int64}, 9223372036854775804:9223372036854775807) with eltype Int64 with indices 9223372036854775804:9223372036854775807:
 1
 2
 3
 4

julia> versioninfo()
Julia Version 1.9.0-DEV.866
Commit 8419acc5ba* (2022-06-30 02:57 UTC)
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 8 × 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-14.0.5 (ORCJIT, tigerlake)
  Threads: 1 on 8 virtual cores
Environment:
  LD_LIBRARY_PATH = :/usr/lib/x86_64-linux-gnu/gtk-3.0/modules
  JULIA_EDITOR = vim

This possibly happens because there is an overflow in

julia/base/array.jl

Line 1891 in 8419acc

@inbounds for i in s:div(s+n-1, 2)

while evaluating div(s+n-1, 2).

julia> s = firstindex(vo)
9223372036854775804

julia> n = lastindex(vo)
9223372036854775807

julia> div(s + n - 1, 2)
-3

[jishnub]

Should we include something like Base.Sort.midpoint in Base? This seems useful, and may help avoid such overflow bugs.