Random stdlib: randstring(rand(UInt8)) errors

[thomvet]

My aim here was to generate a random string of random length with a maximum length of 255 letters.
So, I tried the following:

using Random
s = randstring(rand(UInt8))

which errors with:

ERROR: MethodError: no method matching Random.UnsafeView(::Ptr{UInt8}, ::UInt8)

Closest candidates are:
  Random.UnsafeView(::Ptr{T}, ::Int64) where T
   @ Random C:\Users\thvt\AppData\Local\Programs\Julia-1.10.2\share\julia\stdlib\v1.10\Random\src\RNGs.jl:471

Stacktrace:
 [1] randstring(r::TaskLocalRNG, chars::Vector{UInt8}, n::UInt8)
   @ Random C:\Users\thvt\AppData\Local\Programs\Julia-1.10.2\share\julia\stdlib\v1.10\Random\src\misc.jl:79
 [2] randstring(n::UInt8)
   @ Random C:\Users\thvt\AppData\Local\Programs\Julia-1.10.2\share\julia\stdlib\v1.10\Random\src\misc.jl:90
 [3] top-level scope
   @ REPL[23]:1

If explicitly type-casting the result of rand() to Int64 (but not any other Integer type!), it works as expected:

using Random
s = randstring(Int64(rand(UInt8)))

It's not super transparent why that would be necessary and I would have expected it to "just work" with an UInt8 (or any other type <: Integer for that matter) as well.

Maybe one of the methods involved here is overly specific?

Output of versioninfo():

Julia Version 1.10.2
Commit bd47eca2c8 (2024-03-01 10:14 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: 24 × 12th Gen Intel(R) Core(TM) i7-12850HX
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-15.0.7 (ORCJIT, alderlake)
Threads: 24 default, 0 interactive, 12 GC (on 24 virtual cores)