typeof(ref) shown on stdout

[c42f]

I just got the following inscrutable message on stdout while using Revise, and tracked it to LoweredCodeUtils:

ref = :(_1)
typeof(ref) = Core.SlotNumber

Presumably this was emitted by the line here:

LoweredCodeUtils.jl/src/signatures.jl

Line 412 in ff8998f

isa(ref, GlobalRef) || @show ref typeof(ref)

Strangely this doesn't seem to have triggered the assert on the next line (or if it did, the error was swallowed somewhere, because I didn't see an AssertionError).

[c42f]

So far I've only observed this a single time, but I'll post a reproducer if I find one.

[c42f]

I've seen this more than once now, but still no idea what causes it.

[timholy]

Maybe dev LoweredCodeUtils and add a few additional things to @show: bodyparent JuliaInterpreter.whereis(frame)?