Fix property wrongly considered as const if it is modified through an alias

Fixes #4241

internal/compiler/namedreference.rs

@@ -83,13 +83,14 @@ impl NamedReference {
                 return false;
             }
 
-            if check_binding {
-                if let Some(b) = e.bindings.get(self.name()) {
-                    if !b.borrow().analysis.as_ref().map_or(false, |a| a.is_const) {
-                        return false;
-                    }
-                    check_binding = false;
+            if let Some(b) = e.bindings.get(self.name()) {
+                if check_binding && !b.borrow().analysis.as_ref().map_or(false, |a| a.is_const) {
+                    return false;
                 }
+                if !b.borrow().two_way_bindings.iter().all(|n| n.is_constant()) {
+                    return false;
+                }
+                check_binding = false;
             }
             if let Some(decl) = e.property_declarations.get(self.name()) {
                 if let Some(alias) = &decl.is_alias {

tests/cases/issues/issue_4241_alias-const.slint

@@ -0,0 +1,62 @@
+// Copyright © SixtyFPS GmbH <info@slint.dev>
+// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.1 OR LicenseRef-Slint-commercial
+
+
+export component SpinBoxBase {
+    in-out property <int> value;
+}
+
+
+export component SpinBox {
+    in-out property <int> value <=> i-base.value;
+    i-base := SpinBoxBase {
+        width: 100%;
+    }
+    TouchArea {
+        clicked => {
+            i-base.value += 1;
+        }
+    }
+}
+
+
+export component TestCase {
+    width: 100px;
+    height: 100px;
+    trials:=SpinBox {
+        value: 5;
+        width: 100%;
+        height: 100%;
+    }
+    t:=Text {
+        text: "Value: "+ trials.value;
+    }
+    out property <string> val: t.text;
+}
+
+/*
+```cpp
+auto handle = TestCase::create();
+const TestCase &instance = *handle;
+
+assert_eq(instance.get_val(), "Value: 5");
+slint_testing::send_mouse_click(&instance, 5., 5.);
+assert_eq(instance.get_val(), "Value: 6");
+```
+
+```rust
+let instance = TestCase::new().unwrap();
+
+assert_eq!(instance.get_val(), "Value: 5");
+slint_testing::send_mouse_click(&instance, 5., 5.);
+assert_eq!(instance.get_val(), "Value: 6");
+```
+
+```js
+var instance = new slint.TestCase();
+
+assert.equal(instance.val, "Value: 5");
+slintlib.private_api.send_mouse_click(instance, 5., 5.);
+assert.equal(instance.val, "Value: 6");
+```
+*/