Type instability interpolating solution from out of place prob with default solver

[densmojd]

Interpolating a solution from a non-mutating problem definition is type unstable, but using a mutating definition is fine.

MWE:

using OrdinaryDiffEq

function f1(du, u, p, t)
       du .= -u
end

function f2(u, p, t)
       -u
end

sol1 = solve(ODEProblem(f1, [1.0, 2.0, 3.0], (0.0, 10.0)))
sol2 = solve(ODEProblem(f2, [1.0, 2.0, 3.0], (0.0, 10.0)))

@code_warntype sol1(1.0) # type stable
@code_warntype sol2(1.0) # type unstable

I'm using Julia 1.11.1 and OrdinaryDiffEq.jl v6.90.1

[ChrisRackauckas]

@oscardssmith can you look at this one?

[oscardssmith]

looks like a bug with the default solver.

[oscardssmith]

specifically, we seem to be creating the cache with an abstract type incorrectly...

prob = ODEProblem(f2, [1.0, 2.0, 3.0], (0.0, 10.0))
integ = init(prob)
julia> fieldtype(typeof(integ.cache), :cache3)
OrdinaryDiffEqRosenbrock.Rosenbrock23ConstantCache{_A, SciMLBase.TimeDerivativeWrapper{false, ODEFunction{false, SciMLBase.AutoSpecialize, typeof(f2), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED), Nothing, Nothing, Nothing, Nothing}, Vector{Float64}, SciMLBase.NullParameters}, SciMLBase.UDerivativeWrapper{false, ODEFunction{false, SciMLBase.AutoSpecialize, typeof(f2), LinearAlgebra.UniformScaling{Bool}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, typeof(SciMLBase.DEFAULT_OBSERVED), Nothing, Nothing, Nothing, Nothing}, Float64, SciMLBase.NullParameters}, Matrix{Float64}, LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Nothing, ADTypes.AutoFiniteDiff{Val{:forward}, Val{:forward}, Val{:hcentral}}} where _A