`nested task error: unsupported or misplaced expression aliasscope` when using `julia --compile=min`

[ali-ramadhan]

I recently tried using the julia --compile=min flag to spend less time compiling (and more time debugging) but KernelAbstractions.jl started erroring.

Turns out I can reproduce the same error by running the simple memcopy.jl example: https://github.com/JuliaGPU/KernelAbstractions.jl/blob/8c9d7b48fb3b9dbecc5aae7e30e2758f2f71b6d5/examples/memcopy.jl

Couldn't find the --compile flag mentioned in julia --help so maybe it's an internal flag I shouldn't be using.

$ julia --project --compile=min                                                                                                                                                                                            ─╯
               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.6.0 (2021-03-24)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia> include("examples/memcopy.jl")
ERROR: LoadError: TaskFailedException
Stacktrace:
 [1] wait(t::Task)
   @ Base task.jl:317
 [2] wait(::CPU, ev::KernelAbstractions.CPUEvent, progress::Nothing)
   @ KernelAbstractions ~/KernelAbstractions.jl/src/cpu.jl:65
 [3] wait(ev::KernelAbstractions.CPUEvent, progress::Nothing) (repeats 2 times)
   @ KernelAbstractions ~/KernelAbstractions.jl/src/cpu.jl:29
 [4] top-level scope
   @ ~/KernelAbstractions.jl/examples/memcopy.jl:20
 [5] include(fname::String)
   @ Base.MainInclude client.jl:444
 [6] top-level scope
   @ REPL[1]:1

    nested task error: unsupported or misplaced expression aliasscope
    Stacktrace:
     [1] cpu_copy_kernel!(::Matrix{Float64}, ::Matrix{Float64})
       @ none:0 [inlined]
     [2] overdub(::Cassette.Context{nametype(CPUCtx), KernelAbstractions.CompilerMetadata{KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.NoDynamicCheck, CartesianIndex{1}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(8,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}}, Nothing, KernelAbstractions.var"##PassType#257", Nothing, Cassette.DisableHooks}, ::typeof(cpu_copy_kernel!), ::Matrix{Float64}, ::Matrix{Float64})
       @ Cassette none:0
     [3] __thread_run(tid::Int64, len::Int64, rem::Int64, obj::KernelAbstractions.Kernel{CPU, KernelAbstractions.NDIteration.StaticSize{(8,)}, KernelAbstractions.NDIteration.DynamicSize, typeof(cpu_copy_kernel!)}, ndrange::Tuple{Int64}, iterspace::KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(8,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}, args::Tuple{Matrix{Float64}, Matrix{Float64}}, dynamic::KernelAbstractions.NDIteration.NoDynamicCheck)
       @ KernelAbstractions ~/KernelAbstractions.jl/src/cpu.jl:157
     [4] __run(obj::KernelAbstractions.Kernel{CPU, KernelAbstractions.NDIteration.StaticSize{(8,)}, KernelAbstractions.NDIteration.DynamicSize, typeof(cpu_copy_kernel!)}, ndrange::Tuple{Int64}, iterspace::KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(8,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}, args::Tuple{Matrix{Float64}, Matrix{Float64}}, dynamic::KernelAbstractions.NDIteration.NoDynamicCheck)
       @ KernelAbstractions ~/KernelAbstractions.jl/src/cpu.jl:130
     [5] (::KernelAbstractions.var"#33#34"{Nothing, Nothing, typeof(KernelAbstractions.__run), Tuple{KernelAbstractions.Kernel{CPU, KernelAbstractions.NDIteration.StaticSize{(8,)}, KernelAbstractions.NDIteration.DynamicSize, typeof(cpu_copy_kernel!)}, Tuple{Int64}, KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(8,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}, Tuple{Matrix{Float64}, Matrix{Float64}}, KernelAbstractions.NDIteration.NoDynamicCheck}})()
       @ KernelAbstractions ~/KernelAbstractions.jl/src/cpu.jl:22
in expression starting at /home/alir/KernelAbstractions.jl/examples/memcopy.jl:20

Environment:

julia> versioninfo()
Julia Version 1.6.0
Commit f9720dc2eb (2021-03-24 12:55 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-11.0.1 (ORCJIT, skylake)

(KernelAbstractions) pkg> st
     Project KernelAbstractions v0.6.0
      Status `~/KernelAbstractions.jl/Project.toml`
  [79e6a3ab] Adapt v3.2.0
  [72cfdca4] CUDAKernels v0.1.0 `lib/CUDAKernels`
  [7057c7e9] Cassette v0.3.5
  [1914dd2f] MacroTools v0.5.6
  [276daf66] SpecialFunctions v1.3.0
  [90137ffa] StaticArrays v1.1.0
  [b77e0a4c] InteractiveUtils
  [cf7118a7] UUIDs

[vchuravy]

Can you check that https://github.com/JuliaLang/julia/pull/40275 fixes the issue?