Regrssion in automorph-org/automorph + scalatest/scalatest

[WojciechMazur]

Combination of -Ysafe-init, macros and multi source compilation leads to compilation error.
Regression found in automorph-org/automorph, but problem might exist in all projects using Scalatest framework if they define compose common tests comming from different sub-modules

Open CB builds logs

Compiler version

3.3.1-RC5
3.4.0-RC1-bin-20230815-ca6a80e-NIGHTLY-git-ca6a80e
Works in 3.3.0

Bisect points to deb03a7

Minimized code

// macros_0.scala 
object source {
  import scala.quoted._

  class Position()

  object Position {
    def withPosition[T](
        fun: Expr[Position => T]
    )(using quotes: Quotes, typeOfT: Type[T]): Expr[T] = {
      '{
        ${ fun }.apply(new source.Position())
      }
    }
  }
}

trait AnyFreeSpecLike {
  import scala.language.implicitConversions

  protected final class FreeSpecStringWrapper(
      string: String,
      pos: source.Position
  ) {
    def -(fun: => Unit): Unit = fun
  }

  inline implicit def convertToFreeSpecStringWrapper(
      s: String
  ): FreeSpecStringWrapper = {
    ${
      source.Position.withPosition[FreeSpecStringWrapper]('{
        (pos: source.Position) => new FreeSpecStringWrapper(s, pos)
      })
    }
  }
}

// base_0.scala
trait BaseTest extends AnyFreeSpecLike {
  "empty-test" - {}
}

Needs to be compiled in different compilation-unit:

// test_1.scala 
//> using options -Ysafe-init

class MyTest extends BaseTest {
    private val myObject = new {}
    "empty-test" - {}
}

Output

In 3.3.1-RC5 error

-- Error: macros.scala:30:4 ----------------------------------------------------
30 |    ${
   |    ^
   |[Internal error] unexpected tree
   |-> class MyTest extends BaseTest {  [ main.test.scala:3 ]
   |   ^
   |-> implicit inline def convertToFreeSpecStringWrapper(s: String):
   |  AnyFreeSpecLike.this.FreeSpecStringWrapper =
   |  {
   |    ${
   |      {
   |        def $anonfun(using evidence$2: quoted.Quotes):
   |          quoted.Expr[AnyFreeSpecLike.this.FreeSpecStringWrapper] =
   |          source.Position.withPosition[
   |            AnyFreeSpecLike.this.FreeSpecStringWrapper](
   |            '{
   |              {
   |                def $anonfun(pos: source.Position):
   |                  AnyFreeSpecLike.this.FreeSpecStringWrapper =
   |                  {
   |                    new AnyFreeSpecLike.this.FreeSpecStringWrapper(s, pos)
   |                  }
   |                closure($anonfun)
   |              }
   |            }.apply(evidence$2)
   |          )(evidence$2,
   |            quoted.Type.of[AnyFreeSpecLike.this.FreeSpecStringWrapper](
   |              evidence$2)
   |          )
   |        closure($anonfun)
   |      }
   |    }
   |  }:AnyFreeSpecLike.this.FreeSpecStringWrapper
31 |      source.Position.withPosition[FreeSpecStringWrapper]('{
32 |        (pos: source.Position) => new FreeSpecStringWrapper(s, pos)
33 |      })
34 |    }

In nightly warning:

-- Warning: macros.scala:30:4 --------------------------------------------------
30 |    ${
   |    ^
   |    [Internal error] unexpected tree
   |    -> class MyTest extends BaseTest {      [ main.test.scala:3 ]
   |       ^
   |    -> method convertToFreeSpecStringWrapper
31 |      source.Position.withPosition[FreeSpecStringWrapper]('{
32 |        (pos: source.Position) => new FreeSpecStringWrapper(s, pos)
33 |      })
34 |    }

Expectation

Should not throw compilation error when using -Ysafe-init as there is no unsafe inititialization present in scope.

[liufengyun]

Thanks for the minimization @WojciechMazur . I just noticed this one. I'll look into it shortly. Is it blocker?

[nicolasstucki]

@liufengyun we now have the Quote, Splice, QuotePattern, and SplicePattern ASTs. Before that, they were Apply/TypeApply trees. From what I can see dotty.tools.dotc.transform.init.Semantic interpreted them as normal applications. Was this intended? I am unsure if the staging level change would affect the initialization checking algorithm.