Incorrect error with arrow function and parameter passed as reference

[Daaarkling]

Describe the bug
When arrow function is used together with argument passed as reference (&), phpcs display this error "Expected 1 space after "&" operator; 0 found", which is wrong. if space is incorectly (but as suggested) added then phpcs display this error "Expected 0 spaces after reference operator for argument "$stdClass"; 1 found". phpcbf will simply fail on this. If function is written in old fashion way, everything works correctly.

Code sample

// correct (not considering other sniffs)
var_dump(...array_map(function (?stdClass &$stdClass) {return 1;}, [])); 

// Expected 1 space after "&" operator; 0 found
var_dump(...array_map(fn (?stdClass &$stdClass) => 1, [])); 

// 0 spaces after reference operator for argument "$stdClass"; 1 found
var_dump(...array_map(fn (?stdClass & $stdClass) => 1, []));

Custom ruleset
None.

To reproduce
Steps to reproduce the behavior:

1. Create a file called test.php with the code sample above...
2. Run phpcs test.php ...
3. See error message displayed

3 | ERROR | [x] Expected 1 space after "&" operator; 0 found

3 | ERROR | [x] Expected 0 spaces after reference operator for argument "$stdClass"; 1 found

Expected behavior
There should be no error displayed with arrow function and zero space between & and paramerer name

Versions (please complete the following information):

• OS: Ubuntu 20.04 LTS
• PHP: PHP 7.4.7
• PHPCS: 3.5.5, master

Additional context
None.

[jrfnl]

@Daaarkling Thanks for reporting this. I can confirm the bug.

This bug affects both the PSR12.Operators.OperatorSpacing and the Squiz.WhiteSpace.OperatorSpacing sniffs. PR #3103 should fix this for both.

[gsherwood]

The linked PR does fix this issue. The fix will be release in 3.5.7.