`java.sql.Driver` missing from classpath in macro in presentation compiler

[kasiaMarek]

Original issue: https://github.com/scalameta/metals/issues/6494

Compiler version

3.4.2

Minimized code

//> using scala "3.4.2"
//> using dep "com.h2database:h2:2.2.224"

import scala.quoted._

class LoadStuff extends Selectable:
  def selectDynamic(name: String): Any = name

object LoadStuff:
  transparent inline def make = ${ makeImpl }

  private def makeImpl(using Quotes): Expr[Any] =
    import quotes.reflect.*

    Class.forName("org.h2.Driver") // problematic line

    val refinement = Refinement(TypeRepr.of[LoadStuff], "name", TypeRepr.of[String])

    refinement.asType match
      case '[refined] => '{ LoadStuff().asInstanceOf[refined] }

Output

Interactive compiler reports error diagnostics:

java.lang.ClassNotFoundException: java.sql.Driver
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:593)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Class.java:421)
        at java.base/java.lang.Class.forName(Class.java:412)
        at a.LoadStuff$.makeImpl(LoadStuff.scala:13)
        at a.LoadStuff$.inline$makeImpl(LoadStuff.scala:10)

Expectation

Should compile fine and diagnostics should be empty.

[ncreep]

Hi,

Just adding some further info from the original issue.

Thinking about it, this can be further minimized, as this has nothing to do with Selectable. Apparently just being a transparent inline with class loading is enough to trigger this behavior:

object LoadStuff:
  transparent inline def make: Unit = ${ makeImpl }

  private def makeImpl(using Quotes): Expr[Unit] =
    Class.forName("org.h2.Driver")

    '{()}

This too triggers a loss of type-information at the call-site of make.

Removing transparent brings back type information.

Thanks