Weird ambiguity on 1.6 but not on 1.10

[gdalle]

From #83 testing (see the log):

MethodError: +(::SparseConnectivityTracer.Dual{HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}, ::SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}) is ambiguous. Candidates:
    +(x::Real, dy::D) where {P, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}} in SparseConnectivityTracer at /home/runner/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/src/overload_hessian.jl:132
    +(dx::D, y::Real) where {P, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}} in SparseConnectivityTracer at /home/runner/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/src/overload_hessian.jl:122
  Possible fix, define
    +(::Union{D, D, D, D}, ::Union{D, D, D, D}) where {P, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}, P, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}, D<:SparseConnectivityTracer.Dual{P, T}, D<:SparseConnectivityTracer.Dual{P, T}, T<:HessianTracer, D<:SparseConnectivityTracer.Dual{P, T}}
  Stacktrace:
    [1] add_sum(x::SparseConnectivityTracer.Dual{HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}, y::SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}})
      @ Base ./reduce.jl:27
    [2] _mapreduce(f::typeof(identity), op::typeof(Base.add_sum), #unused#::IndexLinear, A::Vector{SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}})
      @ Base ./reduce.jl:411
    [3] _mapreduce_dim
      @ ./reducedim.jl:318 [inlined]
    [4] #mapreduce#678
      @ ./reducedim.jl:310 [inlined]
    [5] mapreduce
      @ ./reducedim.jl:310 [inlined]
    [6] #_sum#688
      @ ./reducedim.jl:878 [inlined]
    [7] _sum
      @ ./reducedim.jl:878 [inlined]
    [8] #_sum#687
      @ ./reducedim.jl:877 [inlined]
    [9] _sum
      @ ./reducedim.jl:877 [inlined]
   [10] #sum#685
      @ ./reducedim.jl:873 [inlined]
   [11] sum
      @ ./reducedim.jl:873 [inlined]
   [12] (::var"#f#179"{ADNLPModel{Float64, Vector{Float64}, Vector{Int64}}})(x::Vector{SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}})
      @ Main ~/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/test/nlpmodels.jl:35
   [13] trace_function(#unused#::Type{SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}}, f::var"#f#179"{ADNLPModel{Float64, Vector{Float64}, Vector{Int64}}}, x::Vector{Float64})
      @ SparseConnectivityTracer ~/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/src/pattern.jl:32
   [14] local_hessian_pattern(f::Function, x::Vector{Float64}, ::Type{BitSet}, ::Type{Set{Tuple{Int64, Int64}}})
      @ SparseConnectivityTracer ~/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/src/pattern.jl:368

[adrhill]

Adding context: this happened on hs87 from OptimizationProblems.jl.

┌ Warning: Global Hessian sparsity failed
│   name = :hs87
│   typeof(e) = MissingPrimalError
└ @ Main ~/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/test/nlpmodels.jl:39
hs87: Error During Test at /home/runner/work/SparseConnectivityTracer.jl/SparseConnectivityTracer.jl/test/nlpmodels.jl:79

[adrhill]

If I had to take a wild guess, convert(eltype(x), Inf) does weird things on tracers and somehow put a HessianTracer in the primal?

[adrhill]

Here the primal type still looks good, being a Float64:

[2] _mapreduce(f::typeof(identity), op::typeof(Base.add_sum), #unused#::IndexLinear, A::Vector{SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}})

Here, something bad happened and the primal became a HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}:

[1] add_sum(x::SparseConnectivityTracer.Dual{HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}}, y::SparseConnectivityTracer.Dual{Float64, HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}})

[adrhill]

Here, something bad happened and the primal became a HessianTracer{BitSet, Set{Tuple{Int64, Int64}}}:

With #101, this should not be possible anymore, which should give us a more informative error. Could you rerun your test once #101 is merged?

[gdalle]

Sure

[gdalle]

It has disappeared from #83 in the latest run, closing