Simplify detecting class properties to improve detection for anonymous classes (#337)

* Add test for anon class with typehint properties

* Remove search for visibility keywords to find properties

This defaults to only using the condition: if a variable is defined
inside a class and not inside a method within a class, then it's a
property.

* Add readonly properties

Author: sirbrillig

Tests/VariableAnalysisSniff/fixtures/AnonymousClassWithPropertiesFixture.php

@@ -41,3 +41,28 @@ public function methodWithStaticVar() {
         echo static::$storedHello;
     }
 };
+
+class ClassWithAnonymousClassAndTypeHints
+{
+		readonly int $main_id;
+		public int $id = 1;
+		public \My\Data|bool $data;
+
+		public function test_1(): object
+		{
+				return new class
+				{
+						readonly int $main_id;
+						public int $id = 123456;
+						public \My\Data|bool $data;
+				};
+		}
+
+		public function test_2(): object
+		{
+				return new class
+				{
+						public $id = 123456;
+				};
+		}
+}

VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php

@@ -864,29 +864,7 @@ protected function processVariableAsUseImportDefinition(File $phpcsFile, $stackP
 	 */
 	protected function processVariableAsClassProperty(File $phpcsFile, $stackPtr)
 	{
-		$propertyDeclarationKeywords = [
-			T_PUBLIC,
-			T_PRIVATE,
-			T_PROTECTED,
-			T_VAR,
-		];
-		$stopAtPtr = $stackPtr - 2;
-		$visibilityPtr = $phpcsFile->findPrevious($propertyDeclarationKeywords, $stackPtr - 1, $stopAtPtr > 0 ? $stopAtPtr : 0);
-		if ($visibilityPtr) {
-			return true;
-		}
-		$staticPtr = $phpcsFile->findPrevious(T_STATIC, $stackPtr - 1, $stopAtPtr > 0 ? $stopAtPtr : 0);
-		if (! $staticPtr) {
-			return false;
-		}
-		$stopAtPtr = $staticPtr - 2;
-		$visibilityPtr = $phpcsFile->findPrevious($propertyDeclarationKeywords, $staticPtr - 1, $stopAtPtr > 0 ? $stopAtPtr : 0);
-		if ($visibilityPtr) {
-			return true;
-		}
-		// it's legal to use `static` to define properties as well as to
-		// define variables, so make sure we are not in a function before
-		// assuming it's a property.
+		// Make sure we are not in a class method before assuming it's a property.
 		$tokens = $phpcsFile->getTokens();
 
 		/** @var array{conditions?: (int|string)[], content?: string}|null */