`World age increment not at top level` regression with v1.3.1

[mortenpi]

It looks like something might have regressed in 1.3.1 (works with 1.3.0; but also still broken with current master, i.e. 6b5623a).

The MWE is a bit weird, so maybe this is actually not supposed to work, but it shows up in the real world in HTTP.jl, which currently fails to precompile on 1.12 and above: https://github.com/JuliaWeb/HTTP.jl/blob/9db9aaded7c942e442b185d03ea5fd212b1b7efe/src/precompile.jl#L34-L38

The following MWE

hello(who::String) = "Hello, $who"
using PrecompileTools: @setup_workload, @compile_workload
@setup_workload begin
    withenv() do
        @compile_workload begin
            hello("x")
        end
    end
end

leads to

ERROR: LoadError: syntax: World age increment not at top level
Stacktrace:
 [1] top-level scope
   @ ~/oss/Example.jl/src/Example.jl:19
 [2] include(mod::Module, _path::String)
   @ Base ./Base.jl:303
 [3] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt128}}, source::Nothing)
   @ Base ./loading.jl:3019
 [4] top-level scope
   @ stdin:5
 [5] eval(m::Module, e::Any)
   @ Core ./boot.jl:489
 [6] include_string(mapexpr::typeof(identity), mod::Module, code::String, filename::String)
   @ Base ./loading.jl:2865
 [7] include_string
   @ ./loading.jl:2875 [inlined]
 [8] exec_options(opts::Base.JLOptions)
   @ Base ./client.jl:329
 [9] _start()
   @ Base ./client.jl:563
in expression starting at /home/mortenpi/oss/Example.jl/src/Example.jl:1
in expression starting at stdin:

Only affects Julia 1.12+ (getting it on 1.12.0-beta1 and 1.13.0-DEV.361), since <= 1.11 installs PrecompileTools 1.2.1.

[benlorenz]

This also affects Plots.jl, see #59 for the backtrace.

[jpthiele]

And it also affects anything downstream of these packages, e.g. GitHub.jl

[timholy]

Oh dear. I was hoping we'd be able to keep this version, because that change fixed a host of other precompilation problems (xref #53).

Thanks for the MWE, first thing I'll do is steal it and add it to the tests.

[Keno]

There's Expr(Symbol("latestworld-if-toplevel")) which might help.

[timholy]

That seems easier than having @setup_workload hoist it out of the expression created by @compile_workload.