From 09f5ff06e91e3ee3105a150ada03f8a650f2c93f Mon Sep 17 00:00:00 2001
From: Aayush Sabharwal <aayush.sabharwal@gmail.com>
Date: Mon, 14 Apr 2025 21:38:27 +0530
Subject: [PATCH] test: test `@named` always wrapping in `ParentScope`

---
 test/odesystem.jl | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/test/odesystem.jl b/test/odesystem.jl
index a45ed99f35..e1479822a5 100644
--- a/test/odesystem.jl
+++ b/test/odesystem.jl
@@ -9,6 +9,7 @@ using SymbolicUtils: issym
 using ForwardDiff
 using ModelingToolkit: value
 using ModelingToolkit: t_nounits as t, D_nounits as D
+using Symbolics: unwrap
 
 # Define some variables
 @parameters σ ρ β
@@ -1732,3 +1733,26 @@ end
     @test obsfn_expr_oop isa Expr
     @test obsfn_expr_iip isa Expr
 end
+
+@testset "`@named` always wraps in `ParentScope`" begin
+    function SysA(; name, var1)
+        @variables x(t)
+        scope = ModelingToolkit.getmetadata(unwrap(var1), ModelingToolkit.SymScope, nothing)
+        @test scope isa ParentScope
+        @test scope.parent isa ParentScope
+        @test scope.parent.parent isa LocalScope
+        return ODESystem(D(x) ~ var1, t; name)
+    end
+    function SysB(; name, var1)
+        @variables x(t)
+        @named subsys = SysA(; var1)
+        return ODESystem(D(x) ~ x, t; systems = [subsys], name)
+    end
+    function SysC(; name)
+        @variables x(t)
+        @named subsys = SysB(; var1 = x)
+        return ODESystem(D(x) ~ x, t; systems = [subsys], name)
+    end
+    @mtkbuild sys = SysC()
+    @test length(unknowns(sys)) == 3
+end