feat(php): 添加对PHP空安全操作符的支持

- 实现了 NullsafePropertyFetch 和 NullsafeMethodCall 的解析支持
- 添加了 parseNullsafePropertyFetch 和 parseNullsafeMethodCall 方法
- 实现了 nullsafe 表达式的完整解析逻辑，包括属性和方法调用链式访问
- 更新了 PropertyDef 类以支持可空类型标记
- 修改了 getNativeMethod 和 findNativeMethod 方法参数类型为 CallLike
- 添加了完整的测试用例覆盖 nullsafe 操作符的各种使用场景

src/Php/CompilerBase.php

@@ -33,6 +33,7 @@ use PhpParser\NodeAbstract;
 use PhpParser\Parser;
 use PhpParser\ParserFactory;
 use PhpParser\PrettyPrinter;
+use PhpParser\Node\Expr\CallLike;
 
 class CompilerBase extends \PhpAot\Core\Translator
 {
@@ -389,6 +390,10 @@ class CompilerBase extends \PhpAot\Core\Translator
                 return $this->parseArrayDimFetch($expr, $this->inAssignExpr);
             case self::EXPR_PROPERTY_FETCH:
                 return $this->parsePropertyFetch($expr, $this->inAssignExpr);
+            case 'Expr_NullsafePropertyFetch':
+                return $this->parseNullsafePropertyFetch($expr);
+            case 'Expr_NullsafeMethodCall':
+                return $this->parseNullsafeMethodCall($expr);
             case 'Expr_BinaryOp_ShiftLeft':
                 return $this->parseBinaryOpShiftLeft($expr);
             case 'Expr_BinaryOp_ShiftRight':
@@ -978,8 +983,15 @@ class CompilerBase extends \PhpAot\Core\Translator
                     $this->fatalError($param, 'Promoted properties are not supported');
                 }
                 $name = $this->parseIdentifier($param->var);
-                $type = $param->type === null ? '' : $param->type;
+                if ($param->type instanceof NullableType) {
-                $propertyDef = new PropertyDef($name, $param->flags, $type, $this->parseParamDefaultValue($param->default));
+                    $type = $param->type->type;
+                    $nullable = true;
+                } else {
+                    $type = $param->type === null ? '' : $param->type;
+                    $nullable = false;
+                }
+                $default = $this->parseParamDefaultValue($param->default);
+                $propertyDef = new PropertyDef($name, $param->flags, $type, $default, $nullable);
                 $this->classDef->properties[$name] = $propertyDef;
             }
             if ($param->variadic and $i !== $last) {
@@ -1522,7 +1534,7 @@ class CompilerBase extends \PhpAot\Core\Translator
         return array_key_exists($this->escapeFunction($name), $this->nativeFunctions);
     }
 
-    protected function getNativeMethod(Node\Expr\MethodCall|Node\Expr\StaticCall $expr, string $class, string $method): string|false
+    protected function getNativeMethod(CallLike $expr, string $class, string $method): string|false
     {
         if (!$this->hasNativeClass($class)) {
             return false;
@@ -3904,7 +3916,7 @@ class CompilerBase extends \PhpAot\Core\Translator
         return $methodDef->flags & Modifiers::PUBLIC;
     }
 
-    protected function findNativeMethod(Node\Expr\MethodCall $expr, string $object, string $method): string|false
+    protected function findNativeMethod(CallLike $expr, string $object, string $method): string|false
     {
         $nativeFunc = '';
         $classDef = null;
@@ -4102,4 +4114,66 @@ class CompilerBase extends \PhpAot\Core\Translator
 
         return $tmpVar;
     }
+
+    protected function parseNullsafePropertyFetch(Node\Expr\NullsafePropertyFetch $expr): string
+    {
+        return $this->parseNullsafeExpr($expr);
+    }
+
+    protected function parseNullsafeMethodCall(Node\Expr\NullsafeMethodCall $expr): string
+    {
+        return $this->parseNullsafeExpr($expr);
+    }
+
+    protected function parseNullsafeExpr(Node\Expr\NullsafePropertyFetch|Node\Expr\NullsafeMethodCall $expr): string
+    {
+        $list = [];
+        $comment = '// Nullsafe Operator: ' . $this->printer->prettyPrint([$expr]);
+
+        while (1) {
+            if ($expr instanceof Node\Expr\NullsafePropertyFetch) {
+                $list[] = ['property', $this->identifierToStr($expr->name, literal: true)];
+                $expr = $expr->var;
+            } elseif ($expr instanceof Node\Expr\NullsafeMethodCall) {
+                $list[] = ['method', $this->identifierToStr($expr->name, literal: true), $expr->args];
+                $expr = $expr->var;
+            } else {
+                if ($this->isVarExpr($expr)) {
+                    $object = $this->parseIdentifier($expr);
+                    if (!$this->hasVar($object)) {
+                        $this->errorUndefinedVariable($expr);
+                    }
+                    $type = $this->getVarType($object);
+                    if ($type === self::TYPE_OBJECT) {
+                        break;
+                    }
+                }
+                $object = $this->addTmpVar(self::TYPE_OBJECT);
+                $this->beforeStmtLines[] = $this->getIndent() . $object . ' = ' . $this->parseIdentifier($expr) . ';';
+                break;
+            }
+        }
+
+        $list = array_reverse($list);
+        $last = array_key_last($list);
+        $tmpFn = $this->genTmpVarName();
+
+        $code = $comment . PHP_EOL . 'auto ' . $tmpFn . ' = [&]() -> ' . self::TYPE_VAR . '{' . PHP_EOL;
+        $update = $this->escapeBool($this->inAssignExpr);
+
+        foreach ($list as $key => $item) {
+            $tmpVar = $this->addTmpVar($key !== $last ? self::TYPE_OBJECT : self::TYPE_VAR);
+            $code .= "if ($object.isNull()) { return " . self::VALUE_NULL . "; }";
+            if ($item[0] == 'property') {
+                $code .= $this->getIndent() . "$tmpVar = $object.attr({$item[1]}, $update);";
+            } else {
+                $args = $this->parseCallArgs($item[2]);
+                $code .= $this->getIndent() . "$tmpVar = $object.exec({$item[1]}, $args);";
+            }
+            $object = $tmpVar;
+        }
+        $code .= $this->getIndent() . "return $object; };";
+        $this->beforeStmtLines[] = $code;
+        return "$tmpFn()";
+    }
 }

src/Php/Entity/PropertyDef.php

@@ -16,13 +16,15 @@ class PropertyDef
     public string $type;
     public int $flags;
     public ?string $default = null;
+    public bool $nullable = false;
 
-    public function __construct(string $name, int $flags, string $type, ?string $default = null)
+    public function __construct(string $name, int $flags, string $type, ?string $default = null, bool $nullable = false)
     {
         $this->flags   = $flags;
         $this->name    = $name;
         $this->type    = $type;
         $this->default = $default;
+        $this->nullable = $nullable;
     }
 
     public function isPrivate(): bool

tests/aot/nullsafe-001.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Nullsafe operator - method and property access
+--FILE--
+<?php
+class User {
+    public function getName(): string {
+        return 'Alice';
+    }
+}
+
+function main() {
+    $user1 = null;
+    var_dump($user1?->getName());
+    $user2 = new User();
+    var_dump($user2?->getName());
+}
+?>
+--EXPECT--
+NULL
+string(5) "Alice"
+

tests/aot/nullsafe-002.phpt

@@ -0,0 +1,89 @@
+--TEST--
+Nullsafe operator - method and property access
+--FILE--
+<?php
+class Customer {
+    public function __construct(
+        public ?Address $address = null,
+        public string $name = "John"
+    ) {}
+    
+    public function getCountry(): ?string {
+        return $this->address?->country ?? 'Unknown';
+    }
+}
+
+class Address {
+    public function __construct(
+        public string $street = "Main St",
+        public string $city = "NYC",
+        public string $country = "USA"
+    ) {}
+    
+    public function getFullAddress(): string {
+        return "{$this->street}, {$this->city}";
+    }
+}
+
+// Test 6: Nullsafe with method returning object
+class ChainTest {
+    public ?Child $child = null;
+
+    public function getChild(): ?Child {
+        return $this->child;
+    }
+}
+
+class Child {
+    public string $name = "Alice";
+
+    public function getName(): string {
+        return $this->name;
+    }
+}
+
+function main() {
+    // Test 1: Nullsafe method call on non-null object
+    $customer1 = new Customer(new Address("5th Avenue", "New York", "USA"));
+    echo $customer1->address?->getFullAddress() . "\n";
+    
+    // Test 2: Nullsafe method call on null object
+    $customer2 = new Customer(null);
+    var_dump($customer2->address?->getFullAddress());
+    
+    // Test 3: Nullsafe property access on non-null object
+    echo $customer1->address?->city . "\n";
+    
+    // Test 4: Nullsafe property access on null object
+    var_dump($customer2->address?->city);
+    
+    // Test 5: Chained nullsafe calls
+    echo strtoupper($customer1?->address?->getFullAddress());
+
+    $test = new ChainTest();
+    $test->child = new Child();
+    
+    // Test 7: Chained nullsafe method calls
+    echo $test->getChild()?->getName() . "\n";
+
+    // Test 8: Chained nullsafe with null in middle
+    $test2 = new ChainTest();
+    var_dump($test2->getChild()?->getName());
+    
+    // Test 9: Nullsafe property access in expression
+    $value = $customer1->address?->street ?? 'No street';
+    echo $value . "\n";
+    
+    // Test 10: Multiple nullsafe in same expression
+    echo ($customer1->address?->city ?? 'Unknown') . ", " . ($customer1->address?->country ?? 'Unknown') . "\n";
+}
+?>
+--EXPECT--
+5th Avenue, New York
+NULL
+New York
+NULL
+5TH AVENUE, NEW YORKAlice
+NULL
+5th Avenue
+New York, USA

tests/aot/nullsafe-003.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Nullsafe operator - method and property access
+--FILE--
+<?php
+class User {
+    public ?stdClass $prop = null;
+}
+
+function main() {
+    $user = new User();
+    var_dump($user?->prop?->data);
+    $user->prop = new stdClass();
+    $user->prop->data = 'hello';
+    var_dump($user?->prop?->data);
+}
+?>
+--EXPECT--
+NULL
+string(5) "hello"

tests/aot/nullsafe-004.phpt

@@ -0,0 +1,28 @@
+--TEST--
+Nullsafe operator - method and property access
+--FILE--
+<?php
+class User1 {
+    public function getName(): string {
+        return 'Alice';
+    }
+}
+
+class User2 {
+    public ?User1 $user = null;
+    public function getUser() {
+        return $this->user;
+    }
+}
+
+function main() {
+    $user = new User2();
+    var_dump($user?->getUser()?->getName());
+
+    $user->user = new User1();
+    var_dump($user?->getUser()?->getName());
+}
+?>
+--EXPECT--
+NULL
+string(5) "Alice"