simplify_fractions removes metadata

[hexaeder]

Simplification of x(t)/p where x(t) is a variable does not change the term but removes metadata from x(t).

import Pkg; Pkg.activate(temp=true); Pkg.add("ModelingToolkit")
using ModelingToolkit

@parameters t p
@variables x(t)

term1 = x/p
term2 = simplify(term1)

for v in get_variables(term1)
    println("\n $v => ", getproperty(v, :metadata))
end

for v in get_variables(term2)
    println("\n $v => ", getproperty(v, :metadata))
end

in term2 the x(t) has not metadata anymore!

This was introduced in ModelingToolkit 8.

[hexaeder]

Seems like the simplify_fractions passes down similarterm to the Walker from MetaTheory since #422. However in the walker the metadata keyword won't get passed (here and here). A recent similar bug was #283 fixed by #284.

cc @0x0f0f0f because it might has to do more with MetaTheory.

[0x0f0f0f]

Seems like the simplify_fractions passes down similarterm to the Walker from MetaTheory since #422. However in the walker the metadata keyword won't get passed (here and here). A recent similar bug was #283 fixed by #284.

cc @0x0f0f0f because it might has to do more with MetaTheory.

Has to do with the design of the walker. Let's see if the walker breaks when passing metatadata down.

[0x0f0f0f]

I think we should merge #436 first, but i'll branch symbolics.jl to see if there's any major breakage (likely).

[hexaeder]

MWE is fixed