Unclear error message with misspecified arguments to at-printf

[johnmyleswhite]

Perhaps not worth trying to improve, but the error message I get when misusing @printf in the following way is not very clear:

julia> i = 1
1

julia> buffer = [0.0]
1-element Array{Float64,1}:
 0.0

julia> output = [0.0]
1-element Array{Float64,1}:
 0.0

julia> @printf("%d\t%f\t%s\n", i, buffer, output[i])
1   ERROR: TypeError: non-boolean (Array{Bool,1}) used in boolean context

Worth trying to improve?

[quinnj]

The big question here is whether we want to do argument checking for things passed to @printf. Even with the code recently overhauled, we still don't restrictions on arguments passed; partly this allows easy integration for custom types that want to "hook into" the Printf machinery. I'm not sure there's a super clean way to check that each argument is a "scalar" either, which is probably roughly what we'd want here.

[vtjnash]

seems okay to me now:

julia> @printf("%d\t%f\t%s\n", i, buffer, output[i])
ERROR: MethodError: no method matching Float64(::Vector{Float64})

Closest candidates are:
  Float64(!Matched::Int128)
   @ Base float.jl:262
  Float64(!Matched::Bool)
   @ Base float.jl:227
  Float64(!Matched::Int16)
   @ Base float.jl:221
  ...

Stacktrace:
 [1] tofloat(x::Vector{Float64})
   @ Printf ~/julia/usr/share/julia/stdlib/v1.11/Printf/src/Printf.jl:486
 [2] fmt(buf::Vector{UInt8}, pos::Int64, arg::Vector{Float64}, spec::Printf.Spec{Val{'f'}})
   @ Printf ~/julia/usr/share/julia/stdlib/v1.11/Printf/src/Printf.jl:503
 [3] fmt
   @ ~/julia/usr/share/julia/stdlib/v1.11/Printf/src/Printf.jl:315 [inlined]
 [4] format(::Vector{UInt8}, ::Int64, ::Printf.Format{Base.CodeUnits{…}, Tuple{…}}, ::Int64, ::Vararg{Any})
   @ Printf ~/julia/usr/share/julia/stdlib/v1.11/Printf/src/Printf.jl:836
 [5] format(::Base.TTY, ::Printf.Format{Base.CodeUnits{…}, Tuple{…}}, ::Int64, ::Vector{Float64}, ::Vararg{Any})
   @ Printf ~/julia/usr/share/julia/stdlib/v1.11/Printf/src/Printf.jl:937
 [6] top-level scope
   @ REPL[9]:1
Some type information was truncated. Use `show(err)` to see complete types.