[TASK] Add native type declarations for AtRuleSet (#1192)

Part of #811

Author: oliverklee

CHANGELOG.md

@@ -35,7 +35,7 @@ Please also have a look at our
   (#641, #772, #774, #778, #804, #841, #873, #875, #891, #922, #923, #933, #958,
   #964, #967, #1000, #1044, #1134, #1136, #1137, #1139, #1140, #1141, #1145,
   #1162, #1163, #1166, #1172, #1174, #1178, #1179, #1181, #1183, #1184, #1186,
-  #1187, #1190)
+  #1187, #1190, #1192)
 - Add visibility to all class/interface constants (#469)
 
 ### Deprecated

config/phpstan-baseline.neon

@@ -36,12 +36,6 @@ parameters:
 			count: 1
 			path: ../src/Rule/Rule.php
 
-		-
-			message: '#^Only booleans are allowed in an if condition, string given\.$#'
-			identifier: if.condNotBoolean
-			count: 1
-			path: ../src/RuleSet/AtRuleSet.php
-
 		-
 			message: '#^Loose comparison via "\!\=" is not allowed\.$#'
 			identifier: notEqual.notAllowed

src/RuleSet/AtRuleSet.php

@@ -27,10 +27,9 @@ class AtRuleSet extends RuleSet implements AtRule
 
     /**
      * @param non-empty-string $type
-     * @param string $arguments
      * @param int<0, max> $lineNumber
      */
-    public function __construct($type, $arguments = '', int $lineNumber = 0)
+    public function __construct(string $type, string $arguments = '', int $lineNumber = 0)
     {
         parent::__construct($lineNumber);
         $this->type = $type;
@@ -45,10 +44,7 @@ public function atRuleName(): string
         return $this->type;
     }
 
-    /**
-     * @return string
-     */
-    public function atRuleArgs()
+    public function atRuleArgs(): string
     {
         return $this->arguments;
     }
@@ -58,7 +54,7 @@ public function render(OutputFormat $outputFormat): string
         $formatter = $outputFormat->getFormatter();
         $result = $formatter->comments($this);
         $arguments = $this->arguments;
-        if ($arguments) {
+        if ($arguments !== '') {
             $arguments = ' ' . $arguments;
         }
         $result .= "@{$this->type}$arguments{$formatter->spaceBeforeOpeningBrace()}{";