ResolvedPhpDocBlock - fix accessing uninitialized property

Author: ondrejmirtes

src/PhpDoc/ResolvedPhpDocBlock.php

@@ -202,6 +202,10 @@ public function merge(array $parents, array $parentPhpDocBlocks): self
 	 */
 	public function changeParameterNamesByMapping(array $parameterNameMapping): self
 	{
+		if (count($this->phpDocNodes) === 0) {
+			return $this;
+		}
+
 		$paramTags = $this->getParamTags();
 
 		$newParamTags = [];