selectDynamic doesn't work with @targetName

[hamzaremmal]

Compiler version

3.3.1

Minimized code

import scala.annotation.targetName

class X extends scala.reflect.Selectable:
	@targetName("hello")
	val `+` = "1"

val x = X()
x.selectDynamic("+")

Output

java.lang.ExceptionInInitializerError
	at Main$.<clinit>(main.scala:14)
	at Main.main(main.scala)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at sbt.Run.invokeMain(Run.scala:144)
	at sbt.Run.execute$1(Run.scala:94)
	at sbt.Run.$anonfun$runWithLoader$5(Run.scala:121)
	at sbt.Run$.executeSuccess(Run.scala:187)
	at sbt.Run.runWithLoader(Run.scala:121)
	at sbt.Run.run(Run.scala:128)
	at com.olegych.scastie.sbtscastie.SbtScastiePlugin$$anon$1.$anonfun$run$1(SbtScastiePlugin.scala:38)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at sbt.util.InterfaceUtil$$anon$1.get(InterfaceUtil.scala:32)
	at sbt.ScastieTrapExit$App.run(ScastieTrapExit.scala:258)
	at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.NoSuchMethodException: Playground$X.+()
	at java.base/java.lang.Class.getMethod(Class.java:2227)
	at scala.reflect.Selectable.applyDynamic(Selectable.scala:38)
	at scala.reflect.Selectable.applyDynamic$(Selectable.scala:11)
	at Playground$X.applyDynamic(main.scala:5)
	at scala.reflect.Selectable.selectDynamic(Selectable.scala:28)
	at scala.reflect.Selectable.selectDynamic$(Selectable.scala:11)
	at Playground$X.selectDynamic(main.scala:5)
	at Playground$.<clinit>(main.scala:10)
	... 17 more

Expectation

It should resolve to the correct field independently of the presence of the @targetName annotation

[hamzaremmal]

We will work on this issue in today's Spree

[bishabosha]

this is a duplicate of #18612

[bishabosha]

the other issue does not specifically mention @targetName, but the its the same issue - i.e. it doesnt rewrite the access to the name in the class file

[bishabosha]

as for the solution, should it be the argument to selectDynamic that is rewritten, or should the implementation of reflect.Selectable contain a lookup table from scala method name to bytecode name?

And in this situation we can't even know at all if the original argument has a target name or not

def doClose(closable: { def close(): Unit }): Unit =
  import reflect.Selectable.reflectiveSelectable
  closable.close()

leading to a crash:

class Resource:
  @scala.annotation.targetName("foo")
  def close(): Unit = println("closed")

scala> doClose(Resource())
java.lang.NoSuchMethodException: rs$line$2$Resource.close()
  at java.base/java.lang.Class.getMethod(Class.java:2395)
  at scala.reflect.Selectable.applyDynamic(Selectable.scala:38)
  at scala.reflect.Selectable.applyDynamic$(Selectable.scala:11)
  at scala.reflect.Selectable$DefaultSelectable.applyDynamic(Selectable.scala:51)
  at rs$line$1$.doClose(rs$line$1:3)

it would seem perhaps that structural types should not be allowed to conform to methods that have targetName

[hamzaremmal]

That's my point of opening this second issue. I was planning of fixing the first issue by encoding the parameter using scala.reflect.NameTransformer.encode. To fix this issue, we will need a more evolved logic and we will probably not cover it during today's spree.

[bishabosha]

Ok I've reopened if we consider that the #18612 can be fixed with just name transformer (and not fix the wider issue in general about not knowing what exactly the bytecode name will be)