Logging inside of a `@match` throws an `AssertionError` on Julia 1.12

[Drvi]

MRE:

julia> @match 1 begin
          1 => @info "aaa"
       end
ERROR: AssertionError: Assertion to tell the compiler about the definedness of this variable
Stacktrace:
 [1] top-level scope
   @ REPL[30]:2
 [2] macro expansion
   @ logging/logging.jl:415 [inlined]

julia> pkgversion(Match)
v"2.4.0"

julia> versioninfo()
Julia Version 1.12.0-rc1
Commit 228edd6610b (2025-07-12 20:11 UTC)
Build Info:
  Official https://julialang.org release
Platform Info:
  OS: macOS (arm64-apple-darwin24.0.0)
  CPU: 10 × Apple M1 Max
  WORD_SIZE: 64
  LLVM: libLLVM-18.1.7 (ORCJIT, apple-m1)
  GC: Built with stock GC
Threads: 1 default, 1 interactive, 1 GC (on 8 virtual cores)

[Drvi]

IIUC, this is caused by macrocalls being expanded one level at a time here

macro my_macro(expr)
    quote
        local a
        a = 1
        @isdefined(a)
    end
end

MacroTools.prewalk((ex)->macroexpand(Main, ex, recursive=false), :(@my_macro _))
quote
    #= REPL[39]:3 =#
    local var"#1109#a"
    #= REPL[39]:4 =#
    var"#1109#a" = 1
    #= REPL[39]:5 =#
    $(Expr(:isdefined, :a))
end

[nickrobinson251]

@gafter we'd love your advice here 🙏

[gafter]

It seems like (but I didn't check) this would be fixed once JuliaLang/julia#49793 is completed. I don't know if JuliaLang/julia#59276 will help (once implemented), as some macros may depend on the scope mangling. I realize this doesn't help you now. I'll look at what else I can do.

[gafter]

@nickrobinson251 I will fix this shortly.

[gafter]

Can you please confirm if #124 fixes this issue for you?

[nickrobinson251]

thanks for working on this! i should be able to test on our full codebase tomorrow, but also the repro at the top should capture the issue sufficiently that you can be confident so long as that's fixed

[nickrobinson251]

I just updated our codebase to the new Match.jl version and confirmed it's all fixed for us on v1.12

Thanks again for fixing this!

(And apologies for not getting back to you sooner, i didn't manage to do this before i went on holiday).