Fix compilation after rebabse and refactor

Author: liufengyun

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

@@ -39,25 +39,20 @@ object Effects {
    *  - the selection chain on a potential is too long
    */
   case class Promote(potential: Potential)(val source: Tree) extends Effect {
-    def size: Int = potential.size
-    def show(using Context): String =
-      potential.show + "↑"
+    def show(using Context): String = potential.show + "↑"
   }
 
   /** Field access, `a.f` */
   case class FieldAccess(potential: Potential, field: Symbol)(val source: Tree) extends Effect {
     assert(field != NoSymbol)
 
-    def size: Int = potential.size
-    def show(using Context): String =
-      potential.show + "." + field.name.show + "!"
+    def show(using Context): String = potential.show + "." + field.name.show + "!"
   }
 
   /** Method call, `a.m()` */
   case class MethodCall(potential: Potential, method: Symbol)(val source: Tree) extends Effect {
     assert(method != NoSymbol)
 
-    def size: Int = potential.size
     def show(using Context): String = potential.show + "." + method.name.show + "!"
   }