Overflow errors in 32-bit operating system

[jdeldre]

This issue came up for a small number of the students in my class. I admit it took me awhile to figure out what their error was, because I couldn't recreate it on my own computer. I don't actually know how many (or which) of the unit definitions in UnitfulUS lead to this error, but here is an example of what happens when one defines a US gallon:

julia> @unit gal "gal" USGallon 231Unitful.inch^3 false

ERROR: LoadError: LoadError: OverflowError: 5000 * 25000000 overflowed for type Int32
Stacktrace:
[1] throw_overflowerr_binaryop(op::Symbol, x::Int32, y::Int32)
@ Base.Checked .\checked.jl:154
[2] checked_mul
@ .\checked.jl:288 [inlined]
[3] *(x::Rational{Int32}, y::Rational{Int32})
@ Base .\rational.jl:311
[4] power_by_squaring(x_::Rational{Int32}, p::Int32)
@ Base .\intfuncs.jl:279
[5] ^
@ .\rational.jl:453 [inlined]
[6] dpow
@ ~.julia\packages\Unitful\PcVKX\src\units.jl:205 [inlined]
[7] basefactor(inex::Float64, ex::Rational{Int32}, eq::Int32, tens::Int32, p::Rational{Int32})
@ Unitful ~.julia\packages\Unitful\PcVKX\src\units.jl:234
[8] basefactor
@ ~.julia\packages\Unitful\PcVKX\src\units.jl:258 [inlined]
[9] map
@ .\tuple.jl:213 [inlined]
[10] basefactor(x::Unitful.FreeUnits{(inch^3,), 𝐋^3, nothing} )
@ Unitful ~.julia\packages\Unitful\PcVKX\src\units.jl:261
[11] top-level scope
@ ~.julia\packages\Unitful\PcVKX\src\user.jl:220
[12] include(mod::Module, _path::String)
@ Base .\Base.jl:386
[13] include(x::String)

I'm sure this error is exceedingly rare: it is still unclear why students in my class are using 32-bit versions of Julia. Might be old architectures, but might also be their mistake.