Changes

• Adds the FunctionLikeToFirstClassCallableRector rule to CodeStyle
• Adds tests for the new rule

Why

This reduces the user of Closures and Arrow functions where they are basically redundant and code be replaced by a First-Class Callable instead of being wrapped in a closure.

-function ($parameter) { return Call::to($parameter); }
+Call::to(...);

Notes

I debated what group this should be in. It could be considered Code Quality but equally it could be Deadcode or even Code Style. I'm happy to change it based on feedback.

Added to Code Style.

Risk

There might be some risk for this if used with closure binding e.g.

$function = function ($foo) { return $this->foo($foo); };
$function->bindTo($obj);

Might end up as

$function = $this->foo(...);
$function->bindTo($obj);

If that's a problem then I can make the rule avoid method calls of $this.