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Rule use_arrow_functions

Anonymous functions with one-liner return statement must use arrow functions.

Warning

Using this rule is risky

Risky when using isset() on outside variables that are not imported with use ().

Examples

Example #1

--- Original
+++ New
 <?php
-foo(function ($a) use ($b) {
-    return $a + $b;
-});
+foo(fn ($a) => $a + $b);

Rule sets

The rule is part of the following rule sets:

• @PHP74Migration:risky

• @PHP80Migration:risky

• @PHP82Migration:risky

References

• Fixer class: PhpCsFixer\Fixer\FunctionNotation\UseArrowFunctionsFixer

• Test class: PhpCsFixer\Tests\Fixer\FunctionNotation\UseArrowFunctionsFixerTest

The test class defines officially supported behaviour. Each test case is a part of our backward compatibility promise.