fanon is a (non-const) global variable:
julia> using StaticArrays, BenchmarkTools
julia> vec = [1, 2, 3]
3-element Vector{Int64}:
1
2
3
julia> svec = SA[1, 2, 3]
3-element SVector{3, Int64} with indices SOneTo(3):
1
2
3
julia> const c_fanon = x-> 0
#5 (generic function with 1 method)
julia> @ballocations cfanon($vec)
0
julia> @ballocations cfanon($svec)
0