julia> struct S{T<:Tuple{Vararg{Nothing}}} end

julia> f() = S{<:Tuple{Vararg{Nothing}}}
f (generic function with 1 method)

julia> Base.infer_effects(f, Tuple{})
(?c,+e,!n,+t,+s,+m,+u)

julia> versioninfo()
Julia Version 1.12.0-DEV.489
Commit 29ced9e2a02 (2024-05-08 07:57 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 8 × AMD Ryzen 3 5300U with Radeon Graphics
  WORD_SIZE: 64
  LLVM: libLLVM-17.0.6 (ORCJIT, znver2)
Threads: 6 default, 0 interactive, 6 GC (on 8 virtual cores)