Can not iterate solver before solving

[KronosTheLate]

When attempting to iterate a solver that has not been solved, the user is told that there is no method matching iterate for the solver. Same goes for getindex:

julia> using NonlinearSolve

julia> f(u, p) = u .* u .- 2.0
f (generic function with 1 method)

julia> u0 = (1.0, 2.0) # brackets
(1.0, 2.0)

julia> probB = NonlinearProblem(f, u0)
NonlinearProblem with uType Tuple{Float64, Float64}. In-place: false
u0: (1.0, 2.0)

julia> solver = init(probB, Falsi()) # Can iterate the solver object
NonlinearSolve.BracketingImmutableSolver{NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Falsi, Float64, Float64, SciMLBase.NullParameters, Nothing, NonlinearProblem{Tuple{Float64, Float64}, false, SciMLBase.NullParameters, NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}}}(1, NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}(f, LinearAlgebra.UniformScaling{Bool}(true), nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, SciMLBase.DEFAULT_OBSERVED_NO_TIME, nothing), Falsi(), 1.0, 2.0, -1.0, 2.0, SciMLBase.NullParameters(), false, 1000, NonlinearSolve.DEFAULT, nothing, false, NonlinearProblem{Tuple{Float64, Float64}, false, SciMLBase.NullParameters, NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}}(NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}(f, LinearAlgebra.UniformScaling{Bool}(true), nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, nothing, SciMLBase.DEFAULT_OBSERVED_NO_TIME, nothing), (1.0, 2.0), SciMLBase.NullParameters(), Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}()))

julia> solver[1]
ERROR: MethodError: no method matching getindex(::NonlinearSolve.BracketingImmutableSolver{NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Falsi, Float64, Float64, SciMLBase.NullParameters, Nothing, NonlinearProblem{Tuple{Float64, Float64}, false, SciMLBase.NullParameters, NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}}}, ::Int64)
Stacktrace:
 [1] top-level scope
   @ REPL[6]:1

julia> for s in solver
           @show s
       end
ERROR: MethodError: no method matching iterate(::NonlinearSolve.BracketingImmutableSolver{NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Falsi, Float64, Float64, SciMLBase.NullParameters, Nothing, NonlinearProblem{Tuple{Float64, Float64}, false, SciMLBase.NullParameters, NonlinearFunction{false, typeof(f), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED_NO_TIME), Nothing}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}}})
Closest candidates are:
  iterate(::Union{LinRange, StepRangeLen}) at C:\Users\Dennis Bal\.julia\juliaup\julia-1.7.1+0~x64\share\julia\base\range.jl:826
  iterate(::Union{LinRange, StepRangeLen}, ::Integer) at C:\Users\Dennis Bal\.julia\juliaup\julia-1.7.1+0~x64\share\julia\base\range.jl:826
  iterate(::T) where T<:Union{Base.KeySet{<:Any, <:Dict}, Base.ValueIterator{<:Dict}} at C:\Users\Dennis Bal\.julia\juliaup\julia-1.7.1+0~x64\share\julia\base\dict.jl:695
  ...
Stacktrace:
 [1] top-level scope
   @ .\REPL[7]:1

julia> solver = solve!(solver)
u: 1.414213562373095

julia> solver[1]
1.414213562373095

julia> for s in solver
           @show s
       end
s = 1.414213562373095

However, should the unsolved solver not be an empty collection?

This is especially confusing due to the documentation, which says that you can iterate the solver in the line before it is solved. From http://nonlinearsolve.sciml.ai/dev/tutorials/iterator_interface/ :

f(u, p) = u .* u .- 2.0
u0 = (1.0, 2.0) # brackets
probB = NonlinearProblem(f, u0)
solver = init(probB, Falsi()) # Can iterate the solver object
solver = solve!(solver)