MethodError in TypedSyntax

[fredrikekre]

I don't have an MWE for this, but I get a MethodError: no method matching getindex(::Nothing, ::Int) from this line:

Cthulhu.jl/TypedSyntax/src/node.jl

Line 167 in f4581e8

arg = argcontainer[j]

[manuelbb-upb]

I got the same problem after updating Julia from 1.11.4 to 1.12.5;
I turns out, I did have a logic error in my code and was not propagating keyword arguments all the way through recursive function calls.
However, in my specific scenario the keyword arguments are optional and I did test with no keyword arguments, so the result should be unaffected.
Putting this in my package reproduces the error:

function top(
    args...; 
    kwargs...
)
    if isempty(args)
        return nothing
    end
    return mid(args...)
end

function mid(
    args...;          # CRITICAL LINE; removing the semi-colon makes the error go away
)
    return sub(args...)
end

function sub(
    args...;
    kwargs...
)
    return top(args[1:end-1]...; kwargs...)
end

In the end, removing a single ; made the error go away. Hence, it might be a syntax parsing error somewhere?
Revise is also complaining that it cannot find some method instances.
Originally, I used Vararg type annotations to force specialization, but happens with splatted arguments too.
Or is there a difference in defining func(args...) and func(args...;)?