feat(parser): implement nullsafe operator temporary variable lifecycle management

- Add ownedTmpVars array to track temporary variables in nullsafe operations
- Register object temporary variables when creating nullsafe access chains
- Track intermediate temporary variables during nullsafe traversal
- Add cleanup logic to release C++ temporaries at PHP statement boundaries
- Generate unset calls for tracked temporaries in reverse order
- Create comprehensive test case for nullsafe receiver temporary lifetime
- Verify weak reference target release after nullsafe statement completion

src/Parser/NullsafeAccessTrait.php

@@ -39,6 +39,7 @@ trait NullsafeAccessTrait
     ): string
     {
         $list = [];
+        $ownedTmpVars = [];
         $comment = $this->formatCppLineComment('Nullsafe Operator: ', $this->printer->prettyPrint([$expr]));
 
         while (1) {
@@ -66,6 +67,7 @@ trait NullsafeAccessTrait
                     }
                 }
                 $object = $this->addTmpVar(Type::OBJECT);
+                $ownedTmpVars[] = $object;
                 $this->context->beforeStmtLines[] = $this->getIndent() . $object . ' = ' . $this->parseIdentifier($expr) . ';';
                 break;
             }
@@ -80,6 +82,7 @@ trait NullsafeAccessTrait
 
         foreach ($list as $key => $item) {
             $tmpVar = $this->addTmpVar($key !== $last ? Type::OBJECT : Type::VAR);
+            $ownedTmpVars[] = $tmpVar;
             if ($item[3]) {
                 $code .= "if ({$object}.isNull()) { return " . self::VALUE_NULL . '; }';
             }
@@ -117,6 +120,11 @@ trait NullsafeAccessTrait
         }
         $code .= $this->getIndent() . "return {$object}; };";
         $this->context->beforeStmtLines[] = $code;
+
+        // C++ temporaries are function-scoped; release their zvals at the PHP statement boundary.
+        foreach (array_reverse($ownedTmpVars) as $tmpVar) {
+            $this->context->afterStmtLines[] = $tmpVar . '.unset();';
+        }
         return "{$tmpFn}()";
     }
 

tests/compiler/nullsafe/receiver-temporary-lifetime.phpt

@@ -0,0 +1,55 @@
+--TEST--
+Nullsafe receiver temporaries release weak targets after the statement
+--FILE--
+<?php
+
+final class NullsafeWeakReceiver
+{
+    public string $value = 'probe';
+
+    public function label(): string
+    {
+        return $this->value;
+    }
+}
+
+function methodReceiver(): array
+{
+    $target = new NullsafeWeakReceiver();
+    $weak = WeakReference::create($target);
+    $observed = $weak->get()?->label();
+    unset($target);
+    gc_collect_cycles();
+    return [$observed, $weak->get() === null];
+}
+
+function propertyReceiver(): array
+{
+    $target = new NullsafeWeakReceiver();
+    $weak = WeakReference::create($target);
+    $observed = $weak->get()?->value;
+    unset($target);
+    gc_collect_cycles();
+    return [$observed, $weak->get() === null];
+}
+
+function main(): void
+{
+    var_dump(methodReceiver());
+    var_dump(propertyReceiver());
+}
+
+?>
+--EXPECT--
+array(2) {
+  [0]=>
+  string(5) "probe"
+  [1]=>
+  bool(true)
+}
+array(2) {
+  [0]=>
+  string(5) "probe"
+  [1]=>
+  bool(true)
+}