`Adapt.adapt` on views of block arrays involving `:` is broken

[mtfishman]

For example:

julia> using Adapt: adapt

julia> using BlockArrays: BlockedArray, blockedrange

julia> a = BlockedArray(randn(4), [2, 2])
2-blocked 4-element BlockedVector{Float64}:
 -0.5044442639462945
  0.1718623778654892
 ───────────────────
 -0.8397827142096443
  0.3544223955211385

julia> b = @view a[:]
4-element view(::BlockedArray{…,::Vector{Float64}}, :) with eltype Float64 with indices BlockArrays.BlockedOneTo([2, 4]):
 -0.5044442639462945
  0.1718623778654892
 -0.8397827142096443
  0.3544223955211385

julia> adapt(Array, b)
ERROR: MethodError: no method matching Base.Slice(::Vector{Int64})
The type `Base.Slice` exists, but no method is defined for this combination of argument types when trying to construct it.

Closest candidates are:
  Base.Slice(::Base.Slice)
   @ Base indices.jl:385
  Base.Slice(::T) where T<:AbstractUnitRange
   @ Base indices.jl:383

Stacktrace:
 [1] adapt_structure(to::Type, r::Base.Slice{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}})
   @ Adapt ~/.julia/packages/Adapt/0LkKU/src/base.jl:82
 [2] adapt
   @ ~/.julia/packages/Adapt/0LkKU/src/Adapt.jl:40 [inlined]
 [3] _adapt_tuple_structure
   @ ~/.julia/packages/Adapt/0LkKU/src/base.jl:17 [inlined]
 [4] adapt_structure
   @ ~/.julia/packages/Adapt/0LkKU/src/base.jl:9 [inlined]
 [5] adapt
   @ ~/.julia/packages/Adapt/0LkKU/src/Adapt.jl:40 [inlined]
 [6] adapt_structure(to::Type, A::SubArray{Float64, 1, BlockArrays.BlockedVector{Float64, Vector{…}, Tuple{…}}, Tuple{Base.Slice{…}}, false})
   @ Adapt ~/.julia/packages/Adapt/0LkKU/src/wrappers.jl:10
 [7] adapt(to::Type, x::SubArray{Float64, 1, BlockArrays.BlockedVector{Float64, Vector{…}, Tuple{…}}, Tuple{Base.Slice{…}}, false})
   @ Adapt ~/.julia/packages/Adapt/0LkKU/src/Adapt.jl:40
 [8] top-level scope
   @ REPL[16]:1
 [9] top-level scope
   @ none:1
Some type information was truncated. Use `show(err)` to see complete types.

with:

(adapt) pkg> st
Status `...`
  [79e6a3ab] Adapt v4.3.0
  [8e7c35d0] BlockArrays v1.4.0

julia> versioninfo()
Julia Version 1.11.4
Commit 8561cc3d68d (2025-03-10 11:36 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: macOS (arm64-apple-darwin24.0.0)
  CPU: 10 × Apple M1 Max
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, apple-m1)
Threads: 1 default, 0 interactive, 1 GC (on 8 virtual cores)

[mtfishman]

I think the origin of this is that adapting SubArray in involves adapting the indices:
https://github.com/JuliaGPU/Adapt.jl/blob/v4.3.0/src/wrappers.jl#L10-L11
which in the case of slicing with : are Base.Slice wrapping BlockedOneTo, and adapting BlockedOneTo is defined as:

julia> using Adapt: adapt

julia> using BlockArrays: blockedrange

julia> adapt(Array, blockedrange([2, 2]))
4-element Vector{Int64}:
 1
 2
 3
 4

right now. So a minimal fix could be to overload Adapt.adapt_structure for BlockedOneTo, analogous to the definition for other range types: https://github.com/JuliaGPU/Adapt.jl/blob/v4.3.0/src/base.jl#L69-L85.