remove use of rename in some places

Author: pepijndevos

src/systems/abstractsystem.jl

@@ -226,22 +226,22 @@ function Base.getproperty(sys::AbstractSystem, name::Symbol; namespace=true)
     i = findfirst(x->getname(x) == name, sts)
 
     if i !== nothing
-        return namespace ? rename(sts[i],renamespace(sysname,name)) : sts[i]
+        return namespace ? renamespace(sysname,sts[i]) : sts[i]
     end
 
     if has_ps(sys)
         ps = get_ps(sys)
         i = findfirst(x->getname(x) == name,ps)
         if i !== nothing
-            return namespace ? rename(ps[i],renamespace(sysname,name)) : ps[i]
+            return namespace ? renamespace(sysname,ps[i]) : ps[i]
         end
     end
 
     if has_observed(sys)
         obs = get_observed(sys)
         i = findfirst(x->getname(x.lhs)==name,obs)
         if i !== nothing
-            return namespace ? rename(obs[i].lhs,renamespace(sysname,name)) : obs[i]
+            return namespace ? renamespace(sysname,obs[i]) : obs[i]
         end
     end
 
@@ -321,7 +321,7 @@ function namespace_equation(eq::Equation,name,iv)
 end
 
 function namespace_expr(O::Sym,name,iv)
-    isequal(O, iv) ? O : rename(O,renamespace(name,nameof(O)))
+    isequal(O, iv) ? O : renamespace(name,O)
 end
 
 _symparam(s::Symbolic{T}) where {T} = T

test/variable_scope.jl

@@ -1,13 +1,34 @@
 using ModelingToolkit
 using Test
 
-@variables a b c
+@variables a b c d
 
-b = ParentScope(ParentScope(b))
-c = GlobalScope(c)
+b = ParentScope(b)
+c = ParentScope(ParentScope(c))
+d = GlobalScope(d)
 
 renamed(nss, sym) = nameof(foldr(ModelingToolkit.renamespace, nss, init=sym))
 
 @test renamed([:foo :bar :baz], a) == :foo₊bar₊baz₊a
-@test renamed([:foo :bar :baz], b) == :foo₊b
-@test renamed([:foo :bar :baz], c) == :c
+@test renamed([:foo :bar :baz], b) == :foo₊bar₊b
+@test renamed([:foo :bar :baz], c) == :foo₊c
+@test renamed([:foo :bar :baz], d) == :d
+
+eqs = [
+    0 ~ a
+    0 ~ b
+    0 ~ c
+    0 ~ d
+]
+@named sub4 = NonlinearSystem(eqs, [a, b, c, d], [])
+@named sub3 = NonlinearSystem(eqs, [a, b, c, d], [])
+@named sub2 = NonlinearSystem([], [], [], systems=[sub3, sub4])
+@named sub1 = NonlinearSystem([], [], [], systems=[sub2])
+@named sys = NonlinearSystem([], [], [], systems=[sub1])
+
+names = nameof.(states(sys))
+@test :d in names
+@test :sub1₊c in names
+@test :sub1₊sub2₊b in names
+@test :sub1₊sub2₊sub3₊a in names
+@test :sub1₊sub2₊sub4₊a in names