feat(php): 添加对一等可调用语法的支持

- 在编译器中实现 foo(...) 语法的占位符处理逻辑
- 添加对函数调用占位符的识别和生成支持
- 新增 first-class callable 语法的测试用例
- 实现可调用性检查的正确处理机制

src/Php/CompilerBase.php

@@ -2781,6 +2781,10 @@ class CompilerBase extends \PhpAot\Core\Translator
             $nativeFn = $this->findNativeFunction($name);
             if ($nativeFn) {
                 $expr->setAttribute('nativeCall', $nativeFn);
+                // 函数调用占位符，不是真实的函数调用
+                if (count($expr->args) === 1 and $this->isPlaceholderExpr($expr->args[0])) {
+                    return $this->genPlaceHolder($this->identifierToStr($expr->name));
+                }
                 $this->checkNativeCallArgs($expr, $this->getFunction($nativeFn), $expr->args, $name);
                 try {
                     return self::PREFIX . $nativeFn . '(' . $this->parseNativeCallArgs($expr->args, $nativeFn) . ')';

tests/aot/callable/first-class-callable.phpt

@@ -0,0 +1,39 @@
+--TEST--
+First-class callable syntax foo(...)
+--FILE--
+<?php
+function multiply(int $a, int $b): int {
+    return $a * $b;
+}
+
+class Calculator {
+    public function add(int $a, int $b): int {
+        return $a + $b;
+    }
+
+    public static function sub(int $a, int $b): int {
+        return $a - $b;
+    }
+}
+
+function main(): void {
+    $mul = multiply(...);
+    echo $mul(6, 7) . "\n";
+
+    $calc = new Calculator();
+    $add = $calc->add(...);
+    echo $add(10, 5) . "\n";
+
+    $sub = Calculator::sub(...);
+    echo $sub(10, 3) . "\n";
+
+    var_dump(is_callable('multiply'));
+    var_dump(is_callable('nonexistent'));
+}
+?>
+--EXPECT--
+42
+15
+7
+bool(true)
+bool(false)