StaticLambdaBinding

error on by default quick-fix PHP ≥ 5.4

Group: Probable bugs · PhpStorm name: StaticLambdaBindingInspection

A static closure or arrow function has no bound object: using $this in it, or calling an instance method of the parent class through parent::, fails at runtime. Either drop static or stop relying on the object.

Example

Before

<?php
class Base {
    public function render() {}
    public static function make() {}
}

class Widget extends Base {
    private $label = 'w';

    public function handlers() {
        return [
            function () { return $this->label; },
            static function () { return strtoupper($this->label); },
            static fn ($s) => $s . $this->label,
            static function () { return fn () => 1; },
            static function () { return function () { return $this->label; }; },
            static function () { return fn () => $this->label; },
            static function ($x) { parent::render($x); },
            static fn () => parent::render(),
            static function () { return parent::make(); },
        ];
    }
}

After fix

<?php
class Base {
    public function render() {}
    public static function make() {}
}

class Widget extends Base {
    private $label = 'w';

    public function handlers() {
        return [
            function () { return $this->label; },
            function () { return strtoupper($this->label); },
            fn ($s) => $s . $this->label,
            static function () { return fn () => 1; },
            static function () { return function () { return $this->label; }; },
            function () { return fn () => $this->label; },
            function ($x) { parent::render($x); },
            fn () => parent::render(),
            static function () { return parent::make(); },
        ];
    }
}

Reported:

• line 13: Static closures have no $this; remove 'static' or avoid $this.
• line 14: Static closures have no $this; remove 'static' or avoid $this.
• line 17: Static closures have no $this; remove 'static' or avoid $this.
• line 18: Calling an instance method of the parent class requires an object; this closure is static.
• line 19: Calling an instance method of the parent class requires an object; this closure is static.

Configure

In custos.json:

{
  "rules": {
    "StaticLambdaBinding": {
      "enabled": false
    }
  }
}

Suppress

Before the statement or declaration (or the first statement of the file), either of:

// @custos-ignore StaticLambdaBinding

/**
 * @noinspection StaticLambdaBindingInspection
 */