From 6878d5a3780ac4170668f4d2b6fbda5b5ed25eea Mon Sep 17 00:00:00 2001
From: Aayush Sabharwal <aayush.sabharwal@juliahub.com>
Date: Wed, 13 Mar 2024 15:05:44 +0530
Subject: [PATCH] fix: fix structural_simplify with variables marked as inputs

---
 src/systems/systemstructure.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/systems/systemstructure.jl b/src/systems/systemstructure.jl
index 2871bf7445..4a05618306 100644
--- a/src/systems/systemstructure.jl
+++ b/src/systems/systemstructure.jl
@@ -656,7 +656,7 @@ function _structural_simplify!(state::TearingState, io; simplify = false,
     if has_io
         ModelingToolkit.markio!(state, orig_inputs, io...)
     end
-    if io !== nothing
+    if io !== nothing || any(isinput, state.fullvars)
         state, input_idxs = ModelingToolkit.inputs_to_parameters!(state, io)
     else
         input_idxs = 0:-1 # Empty range