Add a val in Scala 2 macro bundles

[nicolasstucki]

No description provided.

[bishabosha]

[info] Test dotty.tools.vulpix.VulpixUnitTests.runTimeout started
failed because test tests/vulpix-tests/unit/timeout.scala timed out
[=======================================] completed (1/1, 1 failed, 3s)

is this a concern?, CI for 5beb624 failed with this

[nicolasstucki]

It seems like some other issue. I restarted the tests to see what happens.

[bishabosha]

This doesn't work because the val is local to the block, when it needs to be visible in the method selection. I tried out this version below which has the correct signature on the method selection:

def typedPrefix(tree: untpd.RefTree)(splice: Context ?=> Tree => Tree)(using Context): Tree = {
  tryAlternatively {
    splice(typedExpr(tree, defn.AnyType))
  } {
    // Try to type as a macro bundle
    val ref = tree match
      case Ident(name) => untpd.Ident(name.toTypeName).withSpan(tree.span)
      case Select(qual, name) => untpd.Select(qual, name.toTypeName).withSpan(tree.span)
    val bundle = untpd.Apply(untpd.Select(untpd.New(ref), nme.CONSTRUCTOR), untpd.Literal(Constant(null))).withSpan(call.span)
    val bundle1 = typedExpr(bundle, defn.AnyType)
    val bundleVal = SyntheticValDef(NameKinds.UniqueName.fresh("bundle".toTermName), bundle1)
    tpd.Block(List(bundleVal), splice(tpd.ref(bundleVal.symbol)))
  }
}
if ctx.phase.isTyper then
  call match
    case call: untpd.Ident =>
      typedIdent(call, defn.AnyType)
    case untpd.Select(qual: untpd.RefTree, name) =>
      typedPrefix(qual) { qual =>
        val call2 = untpd.Select(untpd.TypedSplice(qual), name).withSpan(call.span)
        typedSelect(call2, defn.AnyType)
      }
    case untpd.TypeApply(untpd.Select(qual: untpd.RefTree, name), targs) =>
      typedPrefix(qual) { qual =>
        val call2= untpd.TypeApply(untpd.Select(untpd.TypedSplice(qual), name), targs).withSpan(call.span)
        typedTypeApply(call2, defn.AnyType)
      }
    case _ =>
      ctx.error("Invalid Scala 2 macro " + call.show, call.sourcePos)
      EmptyTree
else typedExpr(call, defn.AnyType)

[bishabosha]

with the changes I suggested I can successfuly compile and use the polymorphic macro bundle definition in the following:

// src-2/MacroImpl.scala
class MacroImpl(val c: scala.reflect.macros.blackbox.Context) {
  import c.universe._
  def poly[T: c.WeakTypeTag]: Tree = q"${c.weakTypeOf[T].toString}"
}

// src-3/Macros.scala
import scala.language.experimental.macros

object Macros {

  object Bundles {
    def poly[T]: String = macro MacroImpl.poly[T]
    inline def poly[T]: String = ${ Macros3.polyImpl[T] }
  }

  object Macros3 {
    def polyImpl[T: Type](using QuoteContext) = Expr(summon[Type[T]].show)
  }

}

and consume macro from TASTy in Scala 2:

// src-2/TestMacroCompat.scala
object TestMacroCompat extends App {
  import MacroCompat._
  import Bundles._
  assert(poly[String] == "String")
}

[nicolasstucki]

@bishabosha could you push the changes that make it work on your side directly to this PR? As long as it works with your tests it good. If the CI fails after that, I can fix it.

[bishabosha]

done

[bishabosha]

looks like I didn't set the right span

[nicolasstucki]

This .withSpan(call.span) should probably be around the tpd.Block

[bishabosha]

perhaps I overdid it?,

[nicolasstucki]

I removed some of them. Could you check it works with your example?

[bishabosha]

I'm not sure whats happening because the CI is passing but testCompilation tests/pos/i8945.scala fails for me

[bishabosha]

wait CI is still running

[bishabosha]

.withSpan still needs to be added to bundleVal - I'll do it

[bishabosha]

@nicolasstucki the commit I just added also works with my scala 2 testing bd066e1

[bishabosha]

I guess someone else should review this now

changes where made