Use non-reflective call for markForAsyncTransform

Author: retronym

src/main/scala/scala/async/Async.scala

@@ -68,13 +68,16 @@ object Async {
     import c.universe._
     if (!c.compilerSettings.contains("-Xasync")) {
       c.abort(c.macroApplication.pos, "The async requires the compiler option -Xasync (supported only by Scala 2.12.12+ / 2.13.3+)")
-    } else try {
+    } else {
       val awaitSym = typeOf[Async.type].decl(TermName("await"))
       def mark(t: DefDef): Tree = {
-        import language.reflectiveCalls
-        c.internal.asInstanceOf[{
-          def markForAsyncTransform(owner: Symbol, method: DefDef, awaitSymbol: Symbol, config: Map[String, AnyRef]): DefDef
-        }].markForAsyncTransform(c.internal.enclosingOwner, t, awaitSym, Map.empty)
+        try {
+          c.internal.markForAsyncTransform(c.internal.enclosingOwner, t, awaitSym, Map.empty)
+        } catch {
+          case e: ReflectiveOperationException =>
+            c.abort(c.macroApplication.pos, "-Xasync is provided as a Scala compiler option, but the async macro is unable to call c.internal.markForAsyncTransform. " + e.getClass.getName + " " + e.getMessage)
+            t
+        }
       }
       val name = TypeName("stateMachine$async")
       q"""
@@ -84,9 +87,6 @@ object Async {
       }
       new $name().start() : ${c.macroApplication.tpe}
     """
-    } catch {
-      case e: ReflectiveOperationException =>
-        c.abort(c.macroApplication.pos, "-Xasync is provided as a Scala compiler option, but the async macro is unable to call c.internal.markForAsyncTransform. " + e.getClass.getName + " " + e.getMessage)
     }
   }
 }