fix(compiler): 检查构造函数可见性以防止非法调用

phpunit/code/constructor_visibility_private.php

@@ -0,0 +1,11 @@
+<?php
+
+class TestClass
+{
+    private function __construct(){}
+}
+
+function main()
+{
+    new TestClass;
+}

phpunit/code/constructor_visibility_protected.php

@@ -0,0 +1,11 @@
+<?php
+
+class TestClass
+{
+    protected function __construct(){}
+}
+
+function main()
+{
+    new TestClass;
+}

phpunit/code/constructor_visibility_protected_foreign_class.php

@@ -0,0 +1,19 @@
+<?php
+
+class Base
+{
+    protected function __construct(){}
+}
+
+class Other
+{
+    public static function make(): Base
+    {
+        return new Base();
+    }
+}
+
+function main()
+{
+    Other::make();
+}

phpunit/code/trait_constructor_conflict.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+trait TraitA
+{
+    public function __construct()
+    {
+        echo "A\n";
+    }
+}
+
+trait TraitB
+{
+    public function __construct()
+    {
+        echo "B\n";
+    }
+}
+
+class TestClass
+{
+    use TraitA, TraitB;
+}
+
+function main()
+{
+    new TestClass();
+}

phpunit/code/trait_constructor_private.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+trait TestTrait
+{
+    private function __construct()
+    {
+        echo "trait ctor\n";
+    }
+}
+
+class TestClass
+{
+    use TestTrait;
+}
+
+function main()
+{
+    new TestClass();
+}

phpunit/code/trait_constructor_protected.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+trait TestTrait
+{
+    protected function __construct()
+    {
+        echo "trait ctor\n";
+    }
+}
+
+class TestClass
+{
+    use TestTrait;
+}
+
+function main()
+{
+    new TestClass();
+}

phpunit/src/ConstructorVisibilityTest.php

@@ -0,0 +1,57 @@
+<?php
+
+use TypePhp\Exception\TestError;
+
+class ConstructorVisibilityTest extends BaseTest
+{
+    /**
+     * 编译期错误在转换阶段直接以 TestError 抛出，而在桩文件生成阶段
+     * (gen_stub.php) 会被包成 RuntimeException，这里两者都要捕获。
+     */
+    protected function exec(string $expected, string $file): void
+    {
+        try {
+            $this->compile($file);
+        } catch (TestError | \RuntimeException $exception) {
+            $this->assertStringContainsString($expected, $exception->getMessage());
+            return;
+        }
+        $this->fail('Expected compile-time error was not thrown');
+    }
+
+    public function testPrivateConstructorCannotBeCalledFromOutside(): void
+    {
+        // 私有构造器不能从类外部通过 `new` 调用
+        $this->exec('Cannot call private TestClass::__construct()', 'constructor_visibility_private.php');
+    }
+
+    public function testProtectedConstructorCannotBeCalledFromGlobalScope(): void
+    {
+        // 保护构造器不能从全局作用域调用
+        $this->exec('Cannot call protected TestClass::__construct()', 'constructor_visibility_protected.php');
+    }
+
+    public function testProtectedConstructorCannotBeCalledFromNonSubclass(): void
+    {
+        // 保护构造器不能从非子类的其它类内部调用
+        $this->exec('Cannot call protected Base::__construct()', 'constructor_visibility_protected_foreign_class.php');
+    }
+
+    public function testTraitPrivateConstructorCannotBeCalledFromGlobalScope(): void
+    {
+        // trait 提供的私有构造器扁平化后等价于类的私有构造器
+        $this->exec('Cannot call private TestClass::__construct()', 'trait_constructor_private.php');
+    }
+
+    public function testTraitProtectedConstructorCannotBeCalledFromGlobalScope(): void
+    {
+        // trait 提供的保护构造器扁平化后等价于类的保护构造器
+        $this->exec('Cannot call protected TestClass::__construct()', 'trait_constructor_protected.php');
+    }
+
+    public function testConflictingTraitConstructorMustBeResolved(): void
+    {
+        // 两个 trait 各自声明 __construct 时必须显式解决冲突
+        $this->exec('Trait `TraitB` method `__construct` already exists', 'trait_constructor_conflict.php');
+    }
+}

src/CompilerBase.php

@@ -3177,6 +3177,15 @@ class CompilerBase implements PropertyAccessContext
                         if ($classDef->flags & Modifiers::ABSTRACT) {
                             $this->fatalError($expr, "abstract class `{$className}` cannot be instantiated");
                         }
+                        // 检查构造函数可见性（private/protected 在不可访问的上下文中被调用）
+                        $ctor = $this->findConstructor($className);
+                        if ($ctor !== null && !$this->checkAccessible($ctor['classDef'], $ctor['flags'])) {
+                            $this->fatalError(
+                                $expr,
+                                'Cannot call ' . $this->visibilityLabel($ctor['flags']) . ' '
+                                . $ctor['classDef']->getNamespacedName() . '::__construct()'
+                            );
+                        }
                     }
                     $cePtr = $this->getClassEntryPtr($className);
                 }
@@ -3859,6 +3868,39 @@ class CompilerBase implements PropertyAccessContext
         return true;
     }
 
+    /**
+     * 沿继承链查找定义 __construct 的类及其可见性标志。
+     * 返回 ['classDef' => ClassDef, 'flags' => int]，未找到（例如构造函数定义在内部类）时返回 null。
+     *
+     * @return array{classDef: ClassDef, flags: int}|null
+     */
+    protected function findConstructor(string $className): ?array
+    {
+        $current = $className;
+        while ($current !== '' && $current !== null) {
+            if (!$this->hasClass($current)) {
+                return null;
+            }
+            $classDef = $this->getClass($current);
+            if ($classDef->hasMethod('__construct')) {
+                return ['classDef' => $classDef, 'flags' => $classDef->getMethod('__construct')->flags];
+            }
+            $current = $classDef->extends;
+        }
+        return null;
+    }
+
+    protected function visibilityLabel(int $flags): string
+    {
+        if ($flags & Modifiers::PRIVATE) {
+            return 'private';
+        }
+        if ($flags & Modifiers::PROTECTED) {
+            return 'protected';
+        }
+        return 'public';
+    }
+
     protected function genDebugInfo(?NodeAbstract $stmt = null, string $functionName = '', int $startLine = 0): string
     {
         $code = '';

tests/compiler/object_ctor/ctor-visibility-protected-subclass.phpt

@@ -0,0 +1,26 @@
+--TEST--
+Constructor visibility - protected constructor accessible from subclass
+--FILE--
+<?php
+
+class Base
+{
+    protected function __construct(){}
+}
+
+class Sub extends Base
+{
+    public static function make(): Base
+    {
+        return new Base();
+    }
+}
+
+function main()
+{
+    $obj = Sub::make();
+    var_dump($obj instanceof Base);
+}
+?>
+--EXPECT--
+bool(true)

tests/compiler/trait/trait-ctor-basic.phpt

@@ -0,0 +1,27 @@
+--TEST--
+Trait __construct is used by the composing class
+--FILE--
+<?php
+
+declare(strict_types=1);
+
+trait TestTrait
+{
+    public function __construct()
+    {
+        echo "trait ctor\n";
+    }
+}
+
+class TestClass
+{
+    use TestTrait;
+}
+
+function main()
+{
+    new TestClass();
+}
+?>
+--EXPECT--
+trait ctor

tests/compiler/trait/trait-ctor-override.phpt

@@ -0,0 +1,32 @@
+--TEST--
+Class __construct overrides the one provided by a trait
+--FILE--
+<?php
+
+declare(strict_types=1);
+
+trait TestTrait
+{
+    public function __construct()
+    {
+        echo "trait ctor\n";
+    }
+}
+
+class TestClass
+{
+    use TestTrait;
+
+    public function __construct()
+    {
+        echo "class ctor\n";
+    }
+}
+
+function main()
+{
+    new TestClass();
+}
+?>
+--EXPECT--
+class ctor

tests/compiler/trait/trait-ctor-protected-subclass.phpt

@@ -0,0 +1,37 @@
+--TEST--
+Trait protected __construct is accessible from a subclass
+--FILE--
+<?php
+
+declare(strict_types=1);
+
+trait TestTrait
+{
+    protected function __construct()
+    {
+        echo "base ctor\n";
+    }
+}
+
+class BaseClass
+{
+    use TestTrait;
+}
+
+class SubClass extends BaseClass
+{
+    public function __construct()
+    {
+        new BaseClass();
+        echo "sub ctor\n";
+    }
+}
+
+function main()
+{
+    new SubClass();
+}
+?>
+--EXPECT--
+base ctor
+sub ctor

tests/compiler/trait/trait-ctor-with-args.phpt

@@ -0,0 +1,30 @@
+--TEST--
+Trait __construct with arguments and $this property access
+--FILE--
+<?php
+
+declare(strict_types=1);
+
+trait TestTrait
+{
+    private int $value = 0;
+
+    public function __construct(int $value)
+    {
+        $this->value = $value;
+        echo "value=" . $this->value . "\n";
+    }
+}
+
+class TestClass
+{
+    use TestTrait;
+}
+
+function main()
+{
+    new TestClass(42);
+}
+?>
+--EXPECT--
+value=42