PHPantom reports a valid namespaced function as undefined

[yankewei]

Verified on latest main

• I have confirmed this bug still occurs when built from the latest main branch.

PHPantom version / commit

phpantom_lsp 815a400

Installation method

Pre-built binary from GitHub Releases

Operating system

macOS aarch64 (Apple Silicon)

Editor

Zed

Bug description

PHPantom reports a valid namespaced function as undefined, although the function is provided by an installed Composer dependency and works correctly at runtime.

Steps to reproduce

Minimal reproduction

composer.json:

{
    "require": {
        "thecodingmachine/safe": "^3.4"
    }
}

src/main.php:

<?php

require_once __DIR__ . '/../vendor/autoload.php';

$encoded = base64_encode('Hello');
$decoded = \Safe\base64_decode($encoded);

After running composer install:

• PHP executes the code successfully.
• PHPantom reports Function 'Safe\base64_decode' not found.

Error output or panic trace

.phpantom.toml

Additional context

No response