Stacktrace of error in `@mtkmodel` points to MTK internals rather than user code

[baggepinnen]

The new @mtkmodel macro is quite a bit nicer to work with compared to the old boilerplaty way to define models 🎉

One problem I've noticed is that when the model definition contains an error, we now get a useless stacktrace:

julia> @named model = TankWithInput()
ERROR: MethodError: no method matching /(::Num, ::ODESystem)

Closest candidates are:
  /(::Union{Num, SymbolicUtils.Symbolic}, ::Unitful.AbstractQuantity)
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/BsHty/src/systems/validation.jl:2
  /(::Number, ::DiffEqScalar)
   @ SciMLBase ~/.julia/packages/SciMLBase/szsYq/src/operators/basic_operators.jl:63
  /(::Number, ::AbstractGray)
   @ ColorVectorSpace ~/.julia/packages/ColorVectorSpace/tLy1N/src/ColorVectorSpace.jl:309
  ...

Stacktrace:
 [1] __MixingTank__(; name::Symbol, c0::Nothing, T0::Nothing, a1::Nothing, a21::Nothing, a22::Nothing, b::Nothing, k0::Nothing, eps::Nothing, gamma::Nothing, c::Nothing, T::Nothing, T_c::Nothing)
   @ Main ~/.julia/packages/ModelingToolkit/BsHty/src/systems/model_parsing.jl:82
 [2] (::ModelingToolkit.Model{typeof(__MixingTank__), Dict{Symbol, Any}})(; kw::Base.Pairs{Symbol, Symbol, Tuple{Symbol}, NamedTuple{(:name,), Tuple{Symbol}}})
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/BsHty/src/systems/model_parsing.jl:25
 [3] macro expansion
   @ ~/.julia/packages/ModelingToolkit/BsHty/src/systems/abstractsystem.jl:999 [inlined]
 [4] __TankWithInput__(; name::Symbol, in__k::Nothing)
   @ Main ~/.julia/packages/ModelingToolkit/BsHty/src/systems/model_parsing.jl:82
 [5] __TankWithInput__
   @ ~/.julia/packages/ModelingToolkit/BsHty/src/systems/model_parsing.jl:82 [inlined]
 [6] #_#172
   @ ~/.julia/packages/ModelingToolkit/BsHty/src/systems/model_parsing.jl:25 [inlined]
 [7] top-level scope
   @ ~/.julia/packages/ModelingToolkit/BsHty/src/systems/abstractsystem.jl:999

all source lines point into the internals of MTK, none of them points to the error in my source code. I believe there is a way to help the macro point to the relevant source line, but I cannot quite remember how. Errors inside Plots @recipe will at least point to the exact source line in the user defined @recipe

[ChrisRackauckas]

It just needs to be setup so that the linenumbernodes are correct and then it should work out. But with any macro, we need to be very diligent about throwing our own higher level errors since we cannot rely on our syntax aligning with the underlying Julia syntax, so in general we need to take over "all" errors that can happen and make the entire error handling be our own. This is one major reason why I wanted to avoid a front end as much as possible, it ended up being the biggest piece of work when developing Pumas, and it will be a huge amount of work here. That said, we did need a front end so we have to take this on head on 😅