In the mediawiki/core code the Squiz.WhiteSpace.OperatorSpacing was added, but it reports a false positive, see [1]
| ERROR | [x] Expected 1 space after "&" operator; 0 found | | (Squiz.WhiteSpace.OperatorSpacing.NoSpaceAfterAmp) | ERROR | [x] Expected 1 space after "&" operator; 0 found | | (Squiz.WhiteSpace.OperatorSpacing.NoSpaceAfterAmp)
It is not reported, when using the long array syntax, because T_ARRAY is checked.
[1] https://gerrit.wikimedia.org/r/#/c/371474/3/includes/parser/ParserOptions.php