Fix nullable constructor promotion detection (#321)

Author: sirbrillig

Tests/VariableAnalysisSniff/VariableAnalysisTest.php

@@ -194,6 +194,8 @@ public function testClassWithMembersWarnings()
 			115,
 			116,
 			174,
+			202,
+			203,
 		];
 		$this->assertSame($expectedWarnings, $lines);
 	}

Tests/VariableAnalysisSniff/fixtures/ClassWithMembersFixture.php

@@ -195,3 +195,30 @@ public function getMessage(): string {
     return $this->message;
   }
 }
+
+class ClassWithNullableConstructorPromotion {
+  public function __construct(
+        public ?string $name = 'Brent',
+        $unused, // Unused variable $unused
+        ?string $unused2, // Unused variable $unused2
+        public ?string $role,
+        private ?string $role2,
+        protected ?string $role3,
+        public $nickname,
+        private $nickname2,
+        protected $nickname3
+  ) {
+  }
+}
+
+class ClassWithReadonlyNullableConstructorPromotion {
+  public function __construct(
+    private readonly ?string $message,
+    private readonly $name,
+    public readonly ?bool $key
+  ) {}
+
+  public function getMessage(): string {
+    return $this->message;
+  }
+}

VariableAnalysis/Lib/Helpers.php

@@ -1561,6 +1561,15 @@ public static function isConstructorPromotion(File $phpcsFile, $stackPtr)
 			return false;
 		}
 		$prev2Token = $tokens[$prev2Index];
+		// If the token that might be a visibility keyword is a nullable typehint,
+		// ignore it and move back one token further eg: `public ?boolean $foobar`.
+		if ($prev2Token['code'] === 'PHPCS_T_NULLABLE') {
+			$prev2Index = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($prev2Index - 1), $functionIndex, true);
+			if (! is_int($prev2Index)) {
+				return false;
+			}
+		}
+		$prev2Token = $tokens[$prev2Index];
 		if (in_array($prev2Token['code'], Tokens::$scopeModifiers, true)) {
 			return true;
 		}