IMO, rand should be able to accept any sort on Integer, and in this case unsigned is actually the only logical value, so I would call this a bug.

julia> rand(Base.Random.GLOBAL_RNG, 0:10, UInt64(4))

ERROR: MethodError: no method matching rand(::MersenneTwister, ::UnitRange{Int64}, ::UInt64)

Closest candidates are:

rand(::AbstractRNG, !Matched::Integer…) at random.jl:369

rand(::AbstractRNG, !Matched::Type, ::Integer, !Matched::Integer…) at random.jl:372

rand(::AbstractRNG, ::UnitRange{#s267} where #s267<:Union{BigInt, Bool, Signed, Unsigned}) at random.jl:654

…

Stacktrace:

[1] macro expansion at ./REPL.jl:97 [inlined]

[2] (::Base.REPL.##1#2{Base.REPL.REPLBackend})() at ./event.jl:73