UnusedParameterSniff: Fixed false positive

Author: kukulich

SlevomatCodingStandard/Sniffs/Functions/UnusedParameterSniff.php

@@ -4,11 +4,15 @@
 
 use PHP_CodeSniffer\Files\File;
 use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Util\Tokens;
 use SlevomatCodingStandard\Helpers\FunctionHelper;
 use SlevomatCodingStandard\Helpers\SuppressHelper;
 use SlevomatCodingStandard\Helpers\TokenHelper;
 use SlevomatCodingStandard\Helpers\VariableHelper;
+use function array_merge;
+use function in_array;
 use function sprintf;
+use const T_COMMA;
 use const T_VARIABLE;
 
 class UnusedParameterSniff implements Sniff
@@ -55,16 +59,31 @@ public function process(File $phpcsFile, $functionPointer): void
 				break;
 			}
 
-			if (!VariableHelper::isUsedInScope($phpcsFile, $functionPointer, $parameterPointer)) {
-				if (!$isSuppressed) {
-					$phpcsFile->addError(
-						sprintf('Unused parameter %s.', $tokens[$parameterPointer]['content']),
-						$parameterPointer,
-						self::CODE_UNUSED_PARAMETER
-					);
-				} else {
-					$suppressUseless = false;
-				}
+			$previousPointer = TokenHelper::findPrevious(
+				$phpcsFile,
+				array_merge([T_COMMA], Tokens::$scopeModifiers),
+				$parameterPointer - 1,
+				$tokens[$functionPointer]['parenthesis_opener']
+			);
+
+			if ($previousPointer !== null && in_array($tokens[$previousPointer]['code'], Tokens::$scopeModifiers, true)) {
+				$currentPointer = $parameterPointer + 1;
+				continue;
+			}
+
+			if (VariableHelper::isUsedInScope($phpcsFile, $functionPointer, $parameterPointer)) {
+				$currentPointer = $parameterPointer + 1;
+				continue;
+			}
+
+			if (!$isSuppressed) {
+				$phpcsFile->addError(
+					sprintf('Unused parameter %s.', $tokens[$parameterPointer]['content']),
+					$parameterPointer,
+					self::CODE_UNUSED_PARAMETER
+				);
+			} else {
+				$suppressUseless = false;
 			}
 
 			$currentPointer = $parameterPointer + 1;

tests/Sniffs/Functions/UnusedParameterSniffTest.php

@@ -17,7 +17,7 @@ public function testErrors(): void
 	{
 		$report = self::checkFile(__DIR__ . '/data/unusedParameterErrors.php');
 
-		self::assertSame(12, $report->getErrorCount());
+		self::assertSame(13, $report->getErrorCount());
 
 		self::assertSniffError($report, 3, UnusedParameterSniff::CODE_UNUSED_PARAMETER, 'Unused parameter $a.');
 		self::assertSniffError($report, 3, UnusedParameterSniff::CODE_UNUSED_PARAMETER, 'Unused parameter $b.');
@@ -30,10 +30,11 @@ public function testErrors(): void
 		self::assertSniffError($report, 47, UnusedParameterSniff::CODE_UNUSED_PARAMETER, 'Unused parameter $a.');
 		self::assertSniffError($report, 51, UnusedParameterSniff::CODE_UNUSED_PARAMETER, 'Unused parameter $a.');
 		self::assertSniffError($report, 53, UnusedParameterSniff::CODE_UNUSED_PARAMETER, 'Unused parameter $a.');
+		self::assertSniffError($report, 66, UnusedParameterSniff::CODE_UNUSED_PARAMETER, 'Unused parameter $b.');
 
 		self::assertSniffError(
 			$report,
-			63,
+			77,
 			UnusedParameterSniff::CODE_USELESS_SUPPRESS,
 			'Useless @phpcsSuppress SlevomatCodingStandard.Functions.UnusedParameter'
 		);

tests/Sniffs/Functions/data/unusedParameterErrors.php

@@ -1,4 +1,4 @@
-<?php // lint >= 7.4
+<?php // lint >= 8.0
 
 function unusedParameters($a, $b)
 {
@@ -57,6 +57,20 @@ function sameNameParameterInAnotherScope($a)
 	};
 }
 
+
+class PropertyPromotion
+{
+
+	public function __construct(
+		public $a,
+		string $b,
+		private int $c,
+	) {
+
+	}
+
+}
+
 /**
  * @phpcsSuppress SlevomatCodingStandard.Functions.UnusedParameter.UnusedParameter
  */

tests/Sniffs/Functions/data/unusedParameterNoErrors.php

@@ -1,4 +1,4 @@
-<?php // lint >= 7.4
+<?php // lint >= 8.0
 
 function noParameter()
 {
@@ -90,3 +90,15 @@ private static function staticMethodCallViaVariable(string $methodName): ?self
 
 }
 
+class PropertyPromotion
+{
+
+	public function __construct(
+		public $a,
+		private string $b
+	) {
+
+	}
+
+}
+