Don't strictly type the keys

Author: YingboMa

src/systems/diffeqs/odesystem.jl

@@ -125,7 +125,7 @@ function ODESystem(
         Base.depwarn("`default_u0` and `default_p` are deprecated. Use `defaults` instead.", :ODESystem, force=true)
     end
     defaults = todict(defaults)
-    defaults = Dict(value(k) => value(v) for (k, v) in pairs(defaults))
+    defaults = Dict{Any,Any}(value(k) => value(v) for (k, v) in pairs(defaults))
 
     iv′ = value(scalarize(iv))
     dvs′ = value.(scalarize(dvs))

src/systems/nonlinear/nonlinearsystem.jl

@@ -85,7 +85,7 @@ function NonlinearSystem(eqs, states, ps;
     end
     jac = RefValue{Any}(Matrix{Num}(undef, 0, 0))
     defaults = todict(defaults)
-    defaults = Dict(value(k) => value(v) for (k, v) in pairs(defaults))
+    defaults = Dict{Any,Any}(value(k) => value(v) for (k, v) in pairs(defaults))
 
     states = collect(states)
     states, ps = value.(states), value.(ps)