scalar indexing when showing OneHot gpu

[CarloLucibello]

I don't think this is supposed to happen, right @darsnack?

julia> using Flux, CUDA

julia> y = Flux.onehotbatch(rand(1:2, 5), 1:2)
2×5 Flux.OneHotArray{UInt32, 2, 1, 2, Vector{UInt32}}:
 1  0  1  1  0
 0  1  0  0  1


ulia> CUDA.allowscalar(true)

julia> y |> gpu
2×5 Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}}:
┌ Warning: Performing scalar operations on GPU arrays: This is very slow, consider disallowing these operations with `allowscalar(false)`
└ @ GPUArrays ~/.julia/packages/GPUArrays/WV76E/src/host/indexing.jl:43
 1  0  1  1  0
 0  1  0  0  1

julia> CUDA.allowscalar(false)

julia> y |> gpu
2×5 Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}}:
Error showing value of type Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}}:
ERROR: scalar getindex is disallowed
Stacktrace:
  [1] error(s::String)
    @ Base ./error.jl:33
  [2] assertscalar(op::String)
    @ GPUArrays ~/.julia/packages/GPUArrays/WV76E/src/host/indexing.jl:41
  [3] getindex
    @ ~/.julia/packages/GPUArrays/WV76E/src/host/indexing.jl:96 [inlined]
  [4] getindex
    @ ~/.julia/packages/Flux/zDU3v/src/onehot.jl:37 [inlined]
  [5] isassigned(::Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}}, ::Int64, ::Int64)
    @ Base ./abstractarray.jl:507
  [6] alignment(io::IOContext{Base.TTY}, X::Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}}, rows::UnitRange{Int64}, cols::UnitRange{Int64}, cols_if_complete::Int64, cols_otherwise::Int64, sep::Int64)
    @ Base ./arrayshow.jl:67
  [7] _print_matrix(io::IOContext{Base.TTY}, X::AbstractVecOrMat{T} where T, pre::String, sep::String, post::String, hdots::String, vdots::String, ddots::String, hmod::Int64, vmod::Int64, rowsA::UnitRange{Int64}, colsA::UnitRange{Int64})
    @ Base ./arrayshow.jl:201
  [8] #invokelatest#2
    @ ./essentials.jl:707 [inlined]
  [9] invokelatest
    @ ./essentials.jl:706 [inlined]
 [10] print_matrix
    @ ./arrayshow.jl:170 [inlined]
 [11] print_array
    @ ./arrayshow.jl:327 [inlined]
 [12] show(io::IOContext{Base.TTY}, #unused#::MIME{Symbol("text/plain")}, X::Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}})
    @ Base ./arrayshow.jl:368
 [13] (::REPL.var"#38#39"{REPL.REPLDisplay{REPL.LineEditREPL}, MIME{Symbol("text/plain")}, Base.RefValue{Any}})(io::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:220
 [14] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [15] display(d::REPL.REPLDisplay, mime::MIME{Symbol("text/plain")}, x::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:213
 [16] display(d::REPL.REPLDisplay, x::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:225
 [17] display(x::Any)
    @ Base.Multimedia ./multimedia.jl:328
 [18] #15
    @ ~/.julia/packages/Media/ItEPc/src/compat.jl:28 [inlined]
 [19] hookless(f::Media.var"#15#16"{Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}}})
    @ Media ~/.julia/packages/Media/ItEPc/src/compat.jl:14
 [20] render
    @ ~/.julia/packages/Media/ItEPc/src/compat.jl:27 [inlined]
 [21] render(x::Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}})
    @ Media ~/.julia/packages/Media/ItEPc/src/system.jl:160
 [22] display(#unused#::Media.DisplayHook, x::Flux.OneHotArray{UInt32, 2, 1, 2, CuArray{UInt32, 1}})
    @ Media ~/.julia/packages/Media/ItEPc/src/compat.jl:9
 [23] display(x::Any)
    @ Base.Multimedia ./multimedia.jl:328
 [24] #invokelatest#2
    @ ./essentials.jl:707 [inlined]
 [25] invokelatest
    @ ./essentials.jl:706 [inlined]
 [26] print_response(errio::IO, response::Any, show_value::Bool, have_color::Bool, specialdisplay::Union{Nothing, AbstractDisplay})
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:247
 [27] (::REPL.var"#40#41"{REPL.LineEditREPL, Pair{Any, Bool}, Bool, Bool})(io::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:231
 [28] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [29] print_response(repl::REPL.AbstractREPL, response::Any, show_value::Bool, have_color::Bool)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:229
 [30] (::REPL.var"#do_respond#61"{Bool, Bool, REPL.var"#72#82"{REPL.LineEditREPL, REPL.REPLHistoryProvider}, REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::Any, ok::Bool)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:798
 [31] #invokelatest#2
    @ ./essentials.jl:707 [inlined]
 [32] invokelatest
    @ ./essentials.jl:706 [inlined]
 [33] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/LineEdit.jl:2441
 [34] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:1126
 [35] (::REPL.var"#44#49"{REPL.LineEditREPL, REPL.REPLBackendRef})()

[CarloLucibello]

sorry my bad, this is due to the show, I think already made this mistake in the past. Can we fix the show? CuArray don't have this problem.

[darsnack]

Yeah see #1494. It's actually an easy fix now that I think about it. Will get to it later today.