Assertion failed "class defined twice" with testCompilation

[aherlihy]

Compiler version

3.4.2-RC1

Minimized code

$sbt testCompilation tests/pos/shared-classname.scala. Does not fail with scalac tests/pos/shared-classname.scala.

(shortened version of not-looping-implicit.scala with the anonymous classes given the same name).

import scala.deriving.Mirror
import scala.compiletime._
trait Schema[T]
object Schema {
  inline given derived[A]: Schema[A] =
    inline summonInline[Mirror.Of[A]] match {
      case m: Mirror.SumOf[A] =>
        summonInline[Schema[m.MirroredElemTypes]]
        class InlinedSchema extends Schema[A] {}
        new InlinedSchema
      case m: Mirror.ProductOf[A] =>
        class InlinedSchema extends Schema[A] {}
        new InlinedSchema
    }
}
sealed trait InputValue
object InputValue {
  case class T() extends InputValue
}
@main def Test:Schema[InputValue] =
  Schema.derived

Output (click arrow to expand)

completed (0/1, 0 failed, 0s)java.lang.AssertionError: assertion failed: class defined twice class Schema$_$InlinedSchema 7130 6099
	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
	at dotty.tools.dotc.transform.TreeChecker.testDuplicate(TreeChecker.scala:55)
        ...

[nicolasstucki]

Fails Ycheck after genSJSIR

checking t/Test.scala after phase MegaPhase{dropOuterAccessors, checkNoSuperThis, flatten, transformWildcards, moveStatic, expandPrivate, restoreScopes, selectStatic, Collect entry points, collectSuperCalls, repeatableAnnotations}
checking t/Test.scala after phase genSJSIR
java.lang.AssertionError: assertion failed: class defined twice class Schema$_$InlinedSchema 6090 7121
        at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
        at dotty.tools.dotc.transform.TreeChecker.testDuplicate(TreeChecker.scala:55)
        at dotty.tools.dotc.transform.TreeChecker.transformSym(TreeChecker.scala:78)
        at dotty.tools.dotc.core.DenotTransformers$SymTransformer.transform(DenotTransformers.scala:72)

[nicolasstucki]

Minimization

trait Foo

object Foo {
  inline def bar(): Foo =
    class InlinedFoo extends Foo {}
    new InlinedFoo

  inline def foo(): Foo =
    bar()
    class InlinedFoo extends Foo {}
    new InlinedFoo

  def Test: Foo = Foo.foo()
}

[nicolasstucki]

@sjrd could you check if this is an issue with genSJSIR or before that pahse?