InstanceofCanBeUsed

warning on by default quick-fix

Group: Language level migration · PhpStorm name: InstanceofCanBeUsedInspection

Testing an object's class through string comparisons or reflection-like helpers (get_class($o) === 'Foo', is_a($o, 'Foo'), in_array('Foo', class_parents($o)), …) is slower and less readable than the instanceof operator, and hides the class name from refactoring tools. Suggest instanceof when the subject is known to be a non-string value and the named class exists.

Example

Before

<?php

final class Invoice        {}
class Document             {}
class Receipt extends Document {}
interface Printable        {}

function check(Invoice $doc, Document $base, string $name, $loose) {
    return [
        'Invoice' === get_class($doc),
        get_class($doc) <> 'Receipt',
        get_parent_class($base) == "Document",
        \is_a($doc, 'Invoice', FALSE),
        is_subclass_of($base, 'Receipt'),
        in_array('Document', class_parents($base), true),

        get_class($base) === 'Document',
        (get_class($doc)) === 'Invoice',
        get_class($name) == 'Invoice',
        get_class($loose) == 'Invoice',
        is_a($doc, 'Invoice', true),
        is_a($doc, 'Foo'),
        is_a($doc, '\\Invoice'),
        is_a($doc, 'Printable'),
        in_array('Invoice', class_implements($name)),
    ];
}

After fix

<?php

final class Invoice        {}
class Document             {}
class Receipt extends Document {}
interface Printable        {}

function check(Invoice $doc, Document $base, string $name, $loose) {
    return [
        $doc instanceof \Invoice,
        get_class($doc) <> 'Receipt',
        get_parent_class($base) == "Document",
        $doc instanceof \Invoice,
        is_subclass_of($base, 'Receipt'),
        in_array('Document', class_parents($base), true),

        get_class($base) === 'Document',
        (get_class($doc)) === 'Invoice',
        get_class($name) == 'Invoice',
        get_class($loose) == 'Invoice',
        is_a($doc, 'Invoice', true),
        is_a($doc, 'Foo'),
        is_a($doc, '\\Invoice'),
        is_a($doc, 'Printable'),
        in_array('Invoice', class_implements($name)),
    ];
}

Reported:

• line 10: Prefer '$doc instanceof \Invoice'.
• line 11: Consider '!$doc instanceof \Receipt' (not an exact equivalent).
• line 12: Consider '$base instanceof \Document' (not an exact equivalent).
• line 13: Prefer '$doc instanceof \Invoice'.
• line 14: Consider '$base instanceof \Receipt' (not an exact equivalent).
• line 15: Consider '$base instanceof \Document' (not an exact equivalent).

Configure

In custos.json:

{
  "rules": {
    "InstanceofCanBeUsed": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore InstanceofCanBeUsed

/**
 * @noinspection InstanceofCanBeUsedInspection
 */