Enables testing the resetting of lifted local variables

- Adds a hook that lets a derived macro insert additional code
  when zero-ing out a lifted field.
- Adds a variant of the `AsyncId` macro that logs zeroed-out fields.
- Adds a test using this mechanism

1 files changed, 8 insertions, 5 deletions

diff --git a/src/main/scala/scala/async/internal/AsyncMacro.scala b/src/main/scala/scala/async/internal/AsyncMacro.scala
index 1c97ca7..ee49923 100644
--- a/src/main/scala/scala/async/internal/AsyncMacro.scala
+++ b/src/main/scala/scala/async/internal/AsyncMacro.scala
@@ -4,15 +4,18 @@ import scala.tools.nsc.Global
 import scala.tools.nsc.transform.TypingTransformers
 
 object AsyncMacro {
-  def apply(c: reflect.macros.Context, futureSystem0: FutureSystem): AsyncMacro = {
+  def apply(c: reflect.macros.Context, base: AsyncBase): AsyncMacro = {
     import language.reflectiveCalls
     val powerContext = c.asInstanceOf[c.type { val universe: Global; val callsiteTyper: universe.analyzer.Typer }]
     new AsyncMacro {
-      val global: powerContext.universe.type = powerContext.universe
+      val global: powerContext.universe.type   = powerContext.universe
       val callSiteTyper: global.analyzer.Typer = powerContext.callsiteTyper
-      val futureSystem: futureSystem0.type = futureSystem0
-      val futureSystemOps: futureSystem.Ops {val universe: global.type} = futureSystem0.mkOps(global)
-      val macroApplication: global.Tree = c.macroApplication.asInstanceOf[global.Tree]
+      val macroApplication: global.Tree        = c.macroApplication.asInstanceOf[global.Tree]
+      // This member is required by `AsyncTransform`:
+      val asyncBase: AsyncBase                 = base
+      // These members are required by `ExprBuilder`:
+      val futureSystem: FutureSystem           = base.futureSystem
+      val futureSystemOps: futureSystem.Ops {val universe: global.type} = futureSystem.mkOps(global)
     }
   }
 }