Just for reference, Polyester has supported something similar for a while. It might make sense to aim for future versions of Polyester to adopt whatever format gets merged into Base.

https://github.com/JuliaSIMD/Polyester.jl#local-per-thread-storage

Ah, so that's what the question on slack was about :D

I haven't tried it, but does this syntax work with something like

Threads.@threads begin
    buffer = Int[]
    for i in 1:100
        #... use buffer
    end
end

too? Seems more convenient/clear to write than having it all on one line.

The syntax is not very readable, but longer term we probably want a mini dsl ala openmp and it's probably wiser to leave that to packages, so this seem reasonable

Is the overhead of array creation significant? Otherwise it might be simpler to return arrays rather than tuples for further manipulation? And for the outer container, a named tuples rather than a plain tuple?

let would probably be more fitting since in that context you specify variables, i.e.

@threads let x = 1, y = 1
    for i = 1:100
        # body
    end
end

Makes sense. And automatically manage returning the vectors

xs, ys = @threads let x = 1, y = 1
    for i = 1:100
        # body
    end
end

Or have the user be explicit about which entries should comprise the vectors

xs, zs = @threads let x = 1, y = 1
    for i = 1:100
        # body
    end
    z = x + y
    x, z
end