Heads up: Package fails on upcoming 1.3 Julia release

[KristofferC]

When testing this package for the upcoming Julia release the following error occurred:

ERROR: LoadError: LoadError: There was an error during testing
in expression starting at /root/.julia/packages/SymEngine/zSUGO/test/test-dense-matrix.jl:30
in expression starting at /root/.julia/packages/SymEngine/zSUGO/test/runtests.jl:6
Error During Test at /root/.julia/packages/SymEngine/zSUGO/test/test-dense-matrix.jl:30
  Test threw exception
  Expression: prod([subs(det(M) - det(A), x, i) == 0 for i = 2:10]) == true
  ArgumentError: Object can have no free symbols
  Stacktrace:
   [1] N(::SymEngine.BasicType{Val{:Abs}}) at /root/.julia/packages/SymEngine/zSUGO/src/numerics.jl:149
   [2] N(::Basic) at /root/.julia/packages/SymEngine/zSUGO/src/numerics.jl:111
   [3] <(::Basic, ::Basic) at /root/.julia/packages/SymEngine/zSUGO/src/mathops.jl:84
   [4] > at ./operators.jl:294 [inlined]
   [5] #generic_lufact!#134(::Bool, ::typeof(LinearAlgebra.generic_lufact!), ::Array{Basic,2}, ::Val{true}) at /workspace/srcdir/julia/usr/share/julia/stdlib/v1.3/LinearAlgebra/src/lu.jl:146
   [6] #generic_lufact! at ./none:0 [inlined]
   [7] #lu!#133 at /workspace/srcdir/julia/usr/share/julia/stdlib/v1.3/LinearAlgebra/src/lu.jl:130 [inlined]
   [8] #lu! at ./none:0 [inlined]
   [9] #lu#135 at /workspace/srcdir/julia/usr/share/julia/stdlib/v1.3/LinearAlgebra/src/lu.jl:273 [inlined]
   [10] #lu at ./none:0 [inlined] (repeats 2 times)
   [11] det(::Array{Basic,2}) at /workspace/srcdir/julia/usr/share/julia/stdlib/v1.3/LinearAlgebra/src/generic.jl:1420
   [12] (::var"##3#4")(::Int64) at ./none:0
   [13] iterate at ./generator.jl:47 [inlined]
   [14] collect(::Base.Generator{UnitRange{Int64},var"##3#4"}) at ./array.jl:620
   [15] top-level scope at /root/.julia/packages/SymEngine/zSUGO/test/test-dense-matrix.jl:30
   [16] include at ./boot.jl:328 [inlined]
   [17] include_relative(::Module, ::String) at ./loading.jl:1105
   [18] include(::Module, ::String) at ./Base.jl:31
   [19] include(::String) at ./client.jl:432
   [20] top-level scope at /root/.julia/packages/SymEngine/zSUGO/test/runtests.jl:6
   [21] include at ./boot.jl:328 [inlined]
   [22] include_relative(::Module, ::String) at ./loading.jl:1105
   [23] include(::Module, ::String) at ./Base.jl:31
   [24] include(::String) at ./client.jl:432
   [25] top-level scope at none:6
   [26] eval(::Module, ::Any) at ./boot.jl:330
   [27] exec_options(::Base.JLOptions) at ./client.jl:271
   [28] _start() at ./client.jl:468

In 1.3, the pivoted LU is used more frequently (JuliaLang/julia#32989) and it seems that the package can't handle that code path:

https://github.com/JuliaLang/julia/blob/36c59c144122dbf09fc0e1f0f1e9defbbd2f254d/stdlib/LinearAlgebra/src/lu.jl#L132-L150