Cover the reference operator in ImplicitCastSpacing

[dereuromark]

- $a, ! $b and @ f() are already handled by PhpCollective.WhiteSpace.ImplicitCastSpacing. The reference marker is the same shape, so it joins that sniff rather than arriving as a new one.

This closes the last gap against psr2r-sniffer's UnaryOperatorSpacing, which can now be deleted there - & was the only construct it still covered that this standard did not:

Construct	PSR2R's sniff	this sniff, before	this sniff, after
- $a	yes	yes	yes
! $b	no	yes	yes
@ f()	yes	yes	yes
& $list	yes	no	yes

Reference or bitwise and

The preceding token is not enough on its own. In function f(array & $items) the marker follows a type hint, and a type hint looks exactly like the left operand of a bitwise and.

So a reference is a & that stands in front of a variable - or the ellipsis of a by-reference variadic - and either follows something that cannot end a value, or sits inside a parameter list. Requiring the variable on the right is what keeps a default value out of it:

$bad = & $list;                                   // reported
foreach ($items as & $item) {}                    // reported
foreach ($items as $k => & $v) {}                 // reported
function f(array & $items) {}                     // reported
function g(& ...$args) {}                         // reported

$ok = &$list;                                     // untouched
$okBitwise = $a & $b;                             // untouched
$okBoolean = $a && $b;                            // untouched
function h(int $x = self::A & self::B) {}         // untouched

Every one of those is in the fixture.

[Copilot]

Pull request overview

Extends PhpCollective.WhiteSpace.ImplicitCastSpacing to also enforce no whitespace after the reference marker (&) when it is used as a by-reference operator, while leaving bitwise & spacing untouched.

Changes:

• Registers T_BITWISE_AND and adds logic to treat & as an implicit-cast-style operator only when it’s a reference marker.
• Introduces isReferenceOperator() to distinguish reference & from bitwise & (including parameter-list handling).
• Expands the fixture and updates expected fixable error counts accordingly.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
PhpCollective/Sniffs/WhiteSpace/ImplicitCastSpacingSniff.php	Adds & handling with reference-vs-bitwise disambiguation.
tests/PhpCollective/Sniffs/WhiteSpace/ImplicitCastSpacingSniffTest.php	Updates expected error/fix counts to match new fixture cases.
tests/_data/ImplicitCastSpacing/before.php	Adds reference-operator spacing violations to be detected/fixed.
tests/_data/ImplicitCastSpacing/after.php	Adds the expected fixed output for the new reference-operator cases.

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