invalid interval constructed

[lucaferranti]

This is because of this issue in julia: JuliaLang/julia#58432

TL;DR: converting a rational to BigFloat, especially when rounding up or down, has some correctness issues, see code snippet and problem diagnostic in the linked issue

Because of that, sometimes invalid intervals can be constructed

julia> a = 1 // (big(2)^300 + 1)
1//2037035976334486086268445688409378161051468393665936250636140449354381299763336706183397377

julia> aa = interval(BigFloat, a, a)
[4.90909e-91, 4.9091e-91]₂₅₆_com

julia> inf(aa) > sup(aa)
true

julia> interval(inf(aa), sup(aa))
┌ Warning: ill-formed interval [a, b] with a = 4.909093465297726553095771954986275642975215512499449565111549117187105254721716e-91, b = 4.909093465297726553095771954986275642975215512499449565111549117187105254721673e-91 and decoration d = com. NaI is returned
└ @ IntervalArithmetic ~/.julia/packages/IntervalArithmetic/uYe1Q/src/intervals/construction.jl:443
∅₂₅₆_ill

I was expecting the aa construction to return NaI because of the issue in Julia, but it actually silently returns an invalid interval