fix(parser): handle temporary variable cleanup for weak reference expressions

- Add unset() call for temporary variables of type VAR to prevent extended object lifetime
- Ensure weak reference targets are properly released after statement execution
- Add test case for expression temporary lifetime behavior with weak references
- Verify object destruction occurs at correct scope boundaries
- Prevent memory leaks with WeakReference targets in native functions

src/Parser/BinaryOpTrait.php

@@ -535,6 +535,13 @@ trait BinaryOpTrait
         $tmpVar = $this->addTmpVar($type);
         $this->context->beforeStmtLines[] = $tmpVar . ' = ' . $value . ';';
         $this->appendCapturedStmtLinesToContext($afterStmts);
+        if ($type === Type::VAR) {
+            // The declaration is function-scoped, but PHP releases an owned
+            // expression temporary after the statement that consumes it.
+            // Keeping the value here would extend object lifetimes (notably
+            // WeakReference targets) until the native function returns.
+            $this->context->afterStmtLines[] = $tmpVar . '.unset();';
+        }
         return $tmpVar;
     }
 

tests/compiler/basic/weak-reference-expression-lifetime.phpt

@@ -0,0 +1,42 @@
+--TEST--
+Expression temporaries release owned objects at the end of the PHP statement
+--FILE--
+<?php
+
+final class TemporaryLifetimeProbe
+{
+    public static int $destroyed = 0;
+
+    public function __destruct()
+    {
+        self::$destroyed++;
+    }
+}
+
+function make_temporary_probe(): object
+{
+    return new TemporaryLifetimeProbe();
+}
+
+function main(): void
+{
+    $target = new stdClass();
+    $weak = WeakReference::create($target);
+    $liveIdentity = $weak->get() === $target;
+    unset($target);
+    gc_collect_cycles();
+
+    var_dump($liveIdentity);
+    var_dump($weak->get() === null);
+
+    $different = make_temporary_probe() === new stdClass();
+    var_dump($different);
+    var_dump(TemporaryLifetimeProbe::$destroyed);
+}
+
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(false)
+int(1)