@nicolasstucki Can you take a look at this? I get:

-- Error: i3912_2.scala:5:21 ---------------------------------------------------
5 |  val a3: Unit = foo3()
  |                 ^^^^^^
  |Exception occurred while executing macro expansion.
  |java.lang.NoSuchMethodError: scala.quoted.Liftable$.Liftable_Int_delegate()Lscala/quoted/Liftable;
  |	at Macros$.impl(i3912_1.scala:10)
  |
  | This location is in code that was inlined at i3912_2.scala:5
one error found

But I get the same problem when I run this locally at master. So I am not sure what's to blame for it; maybe nothing in the PR itself.

If you switch to master you probably need to clean out/bootstrap/dotty-library-bootstrapped. To make it work again.

That call to Liftable_Int_delegate is generated here. The definition of that delegate is here.

I noticed that the signature in the bytecode changed from

public final PrimitiveLiftable<Object> Liftable_Int_delegate()

to

public final Liftable<Object> Liftable_Int_delegate()

This might be the source of the problem.

I noticed that the signature in the bytecode changed from

public final PrimitiveLiftable<Object> Liftable_Int_delegate()

to

public final Liftable<Object> Liftable_Int_delegate()

This might be the source of the problem.

Yes, that looks likely. The new type, Liftable, is the correct one. If the result type should be PrimitiveLiftable the given instance has to be declared as one.

Sorry, I inverted the snippets. Master has Liftable<Object> and this branch has PrimitiveLiftable<Object>.

Yes, now the signature is wrong.

I forced it to have Liftable and it worked.

given Liftable_Int_delegate as Liftable[Int] = primitiveLiftable

private def primitiveLiftable[T <: Unit | Null | Int | Boolean | Byte | Short | Int | Long | Float | Double | Char | String]: Liftable[T] = new PrimitiveLiftable

private class PrimitiveLiftable[T <: Unit | Null | Int | Boolean | Byte | Short | Int | Long | Float | Double | Char | String] extends Liftable[T] {
  ....
}

OK, I am out of my wits here. dotty-library-bootstrappedJS fails with this error:

error] Illegal tree in gen of genInterface(): ValDef(OFFSET$_m_0,TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,module class scala)),class Long)],Apply(Select(Ident(LazyVals),getOffset),List(Literal(Constant(ClassInfo(NoPrefix, module class Liftable$, List(TypeRef(ThisType(TypeRef(NoPrefix,module class lang)),class Object), TypeRef(ThisType(TypeRef(NoPrefix,module class scala)),class Serializable))))), Literal(Constant(bitmap$0)))))
--
18376 | [error] (dotty-library-bootstrappedJS / Compile / compileIncremental) Compilation failed

It seems that it tries to generate a lazy val offset variable in an interface. The lazy val is probably generated from the given cache. But the generated lazy val seems to be exactly the same as a user-written one. Who can help and find out what the problem is? Maybe someone has a better idea what this could be. Or we need to start triaging to figure out exactly what file fails. It would be good to finally fix #6909 which has already tripped up several people.

Here's a more informative error message:

Illegal tree in gen of genInterface(): @scala.annotation.static() @scala.annotation.static() val OFFSET$_m_0: Long =
--
18388 | [error] dotty.runtime.LazyVals.getOffset(classOf[Object with Serializable {...}],
18389 | [error] "bitmap$0"
18390 | [error] )
18391 | [error] class = @scala.annotation.internal.SourceFile(
18392 | [error] "/tmp/2/library/src-bootstrapped/scala/quoted/Liftable.scala"
18393 | [error] ) trait Liftable() extends Object {
18394 | [error] @scala.annotation.static() private def <clinit>(): Unit =
18395 | [error] {
18396 | [error] Liftable.this.OFFSET$_m_0 =
18397 | [error] dotty.runtime.LazyVals.getOffset(classOf[Object with Serializable {...}]
18398 | [error] ,
18399 | [error] "bitmap$0")
18400 | [error] ()
18401 | [error] }
18402 | [error] def toExpr(x: Object): Function1
18403 | [error] def toExpr$direct(x: Object, x$0: scala.quoted.QuoteContext):
18404 | [error] scala.quoted.Expr
18405 | [error] @scala.annotation.static() @scala.annotation.static() val OFFSET$_m_0: Long =
18406 | [error] dotty.runtime.LazyVals.getOffset(classOf[Object with Serializable {...}],
18407 | [error] "bitmap$0"
18408 | [error] )
18409 | [error] }
18410 | [error] in /tmp/2/library/src-bootstrapped/scala/quoted/Liftable.scala
18411 | [error] (dotty-library-bootstrappedJS / Compile / compileIncremental) Compilation failed

The OFFSET field has the static annotation (twice!, no idea why) so it should be legal in an interface.

@sjrd Can you suggest how to fix this?

We have an annoying problem here:

• We need to fix Erased terms can't be passed to erased lambda argument #6009, urgently.
• Lazyvals causes the current problem by creating a static ValDef in a trait that JS does not handle.
• Lazyvals will likely be rewritten soon, but we need a fix of Erased terms can't be passed to erased lambda argument #6009 before that happens.
• The least path of resistance would be to disable Js generation for now, since we do not need it anyway.
• Anybody has a better alternative?

In fact, it's likely that a revised LazyVals would also need to generate static ValDefs in traits, so the problem should be fixed on the Js generation side.

I will see what I can do today. I believe the easiest is actually to change the lazy val transform so that it generates something simpler for JS. The current scheme and the new proposed scheme are both unsuitable for JS, because they use Unsafe, and are completely overkill for a single-threaded environment anyway.

I will see what I can do today. I believe the easiest is actually to change the lazy val transform so that it generates something simpler for JS. The current scheme and the new proposed scheme are both unsuitable for JS, because they use Unsafe, and are completely overkill for a single-threaded environment anyway.

Indeed. Maybe it's simplest to always assume @ThreadUnsafe for lazy vals under JS?