NewWithoutParenthesesSniff removes constructor parentheses and produces invalid syntax when method chaining

[martinbohmcz]

Bug description

SlevomatCodingStandard.ControlStructures.NewWithoutParentheses incorrectly removes
empty constructor parentheses from new ClassName() when the expression is immediately
chained with ->method(). The resulting code is a parse error in PHP 8.4 and earlier.

Versions

• slevomat/coding-standard: 8.27.1
• PHP: 8.4.4

Steps to reproduce

<?php
$date = new DateTime()->setTime(0, 0);

Run phpcbf with SlevomatCodingStandard.ControlStructures.NewWithoutParentheses enabled.

Actual result

<?php
$date = new DateTime->setTime(0, 0);

Expected result

No change – the sniff should leave the code untouched.

Why this is a bug

PHP 8.4 added support for new Foo()->method() (chaining directly without outer
parentheses). However, new Foo->method() – without constructor () – is still
a parse error in PHP 8.4:

Parse error: syntax error, unexpected token "->", expecting ")" in ...

The sniff correctly detects that () contains no arguments, but does not check
what follows the closing ). When an object operator -> (or ::) follows, the
parentheses are not useless – they are required for the expression to be valid.

Root cause

In NewWithoutParenthesesSniff::process(), after confirming the parentheses are empty
(lines 81–84), there is no check for what token follows the closing ). A fix would be
to add before line 86:

$afterCloser = TokenHelper::findNextEffective(
    $phpcsFile,
    $tokens[$parenthesisOpenerPointer]['parenthesis_closer'] + 1,
);
if (in_array($tokens[$afterCloser]['code'], [T_OBJECT_OPERATOR, T_NULLSAFE_OBJECT_OPERATOR, T_DOUBLE_COLON], true)) {
    return;
}

Workaround

<rule ref="SlevomatCodingStandard.ControlStructures.NewWithoutParentheses">
    <exclude name="SlevomatCodingStandard.ControlStructures.NewWithoutParentheses.UselessParentheses"/>
</rule>