Update compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

Co-authored-by: Ondřej Lhoták <[email protected]>

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

@@ -1146,7 +1146,7 @@ object Semantic:
     private val pendingTasks: mutable.ArrayBuffer[Task] = new mutable.ArrayBuffer
 
     def addTask(task: Task): Unit =
-      if !pendingTasks.contains(task) then pendingTasks += task
+      if !pendingTasks.contains(task) then pendingTasks.append(task)
 
     /** Process the worklist until done */
     final def work()(using Cache, Context): Unit =