jchyb
commented
1 year ago Better minimization:
// codecs.scala
package internal
import scala.deriving._
import scala.quoted._
class Encoder[A]
object Encoder:
inline def derived[A](): Encoder[A] =
val instances = Macros.summonEncoders[Int]
new Encoder[A]
// causes the classloader to fail
def methodWithContext[A](using ctx: Context): Encoder[A] = new Encoder[A]
inline given unionEncoder[U]: Encoder[U] = ${ unionEncoderImpl[U] }
private def unionEncoderImpl[U: scala.quoted.Type](using Quotes): Expr[Encoder[U]] = '{new Encoder[U]}
// Context.scala
package internal
class Context()
object Other {
def methodCallingMacro(): Unit =
Encoder.derived[Int]()
}// Macros.scala
package internal
import scala.quoted.*
object Macros:
inline def summonEncoders[A]: Unit = ${ summonEncodersImpl[A] }
private def summonEncodersImpl[A: Type](using Quotes): Expr[Unit] =
Expr.summon[Encoder[Int]]
'{ () }Interestingly, if the packages are removed, the error changes into the even less descriptive SuspendException.
It looks like the Context.scala CompileationUnit becomes suspended, and after compiling the other files, when compiler returns to Context.scala it tries to inline the derived method, for which it calls the Macros macro, where to summon the Encoder it tries to expand the unionEncoder by calling the MacroClassLoader to classload the Encoder, which it fails to do because of unknown (from the ClassLoader point of view, since the file Context.class was not generated yet at that point) class Context.
Calling the failing unionEncoder macro directly leads to a slightly different error/crash, outside of the macro expansion context:
MInimization
// Context.scala
package internal
class Context()
object Other {
def methodCallingMacro(): Unit =
Encoder.unionEncoder[Int]
}// codecs.scala
package internal
import scala.deriving._
import scala.quoted._
class Encoder[A]
object Encoder:
def methodWithContext[A](using ctx: Context): Encoder[A] = new Encoder[A]
inline def unionEncoder[U]: Encoder[U] = ${ unionEncoderImpl[U] }
private def unionEncoderImpl[U: scala.quoted.Type](using Quotes): Expr[Encoder[U]] = '{new Encoder[U]}Output
```
java.lang.NoClassDefFoundError: internal/Context while running inlining on /Users/jchyb/Documents/workspace/dotty/zerr/Context.scala
java.lang.NoClassDefFoundError: internal/Context while compiling /Users/jchyb/Documents/workspace/dotty/zerr/Context.scala, /Users/jchyb/Documents/workspace/dotty/zerr/Macros.scala, /Users/jchyb/Documents/workspace/dotty/zerr/codecs.scala
Exception in thread "main" java.lang.NoClassDefFoundError: internal/Context
at java.base/java.lang.Class.getDeclaredMethods0(Native Method)
at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3402)
at java.base/java.lang.Class.getMethodsRecursive(Class.java:3543)
at java.base/java.lang.Class.getMethod0(Class.java:3529)
at java.base/java.lang.Class.getMethod(Class.java:2225)
at dotty.tools.dotc.transform.Splicer$Interpreter.getMethod(Splicer.scala:428)
at dotty.tools.dotc.transform.Splicer$Interpreter.interpretedStaticMethodCall(Splicer.scala:375)
at dotty.tools.dotc.transform.Splicer$Interpreter.interpretTree(Splicer.scala:268)
at dotty.tools.dotc.transform.Splicer$Interpreter.interpretTree$$anonfun$2(Splicer.scala:289)
at dotty.tools.dotc.transform.Splicer$.$anonfun$2(Splicer.scala:57)
at scala.Option.fold(Option.scala:263)
at dotty.tools.dotc.transform.Splicer$.splice(Splicer.scala:57)
at dotty.tools.dotc.inlines.Inliner.dotty$tools$dotc$inlines$Inliner$$expandMacro(Inliner.scala:1038)
at dotty.tools.dotc.inlines.Inliner$InlineTyper.typedApply(Inliner.scala:816)
at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2895)
at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2958)
at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:126)
at dotty.tools.dotc.inlines.Inliner$InlineTyper.typedUnadapted(Inliner.scala:900)
at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3025)
at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3029)
at dotty.tools.dotc.typer.ReTyper.typedTyped(ReTyper.scala:64)
at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2900)
at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2958)
at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:126)
at dotty.tools.dotc.inlines.Inliner$InlineTyper.typedUnadapted(Inliner.scala:900)
at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3025)
at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3022)
at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3029)
at dotty.tools.dotc.inlines.Inliner.inlined(Inliner.scala:671)
at dotty.tools.dotc.inlines.Inlines$InlineCall.expand(Inlines.scala:451)
at dotty.tools.dotc.inlines.Inlines$.inlineCall(Inlines.scala:148)
at dotty.tools.dotc.transform.Inlining$InliningTreeMap.transform(Inlining.scala:70)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1225)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1225)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformBlock(tpd.scala:1230)
at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1426)
at dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:49)
at dotty.tools.dotc.transform.Inlining$InliningTreeMap.transform(Inlining.scala:66)
at dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:56)
at dotty.tools.dotc.transform.Inlining$InliningTreeMap.transform(Inlining.scala:64)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1225)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1225)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1227)
at dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:64)
at dotty.tools.dotc.transform.Inlining$InliningTreeMap.transform(Inlining.scala:64)
at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1480)
at dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:73)
at dotty.tools.dotc.transform.Inlining$InliningTreeMap.transform(Inlining.scala:64)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1225)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1225)
at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1227)
at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1488)
at dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:73)
at dotty.tools.dotc.transform.Inlining$InliningTreeMap.transform(Inlining.scala:76)
at dotty.tools.dotc.transform.Inlining$$anon$2.transform(Inlining.scala:56)
at dotty.tools.dotc.transform.MacroTransform.run(MacroTransform.scala:18)
at dotty.tools.dotc.transform.Inlining.run(Inlining.scala:28)
at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:316)
at scala.collection.immutable.List.map(List.scala:246)
at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:320)
at dotty.tools.dotc.transform.Inlining.runOn(Inlining.scala:32)
at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:238)
at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1321)
at dotty.tools.dotc.Run.runPhases$1(Run.scala:249)
at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:257)
at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:266)
at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:68)
at dotty.tools.dotc.Run.compileUnits(Run.scala:266)
at dotty.tools.dotc.Run.compileUnits(Run.scala:196)
at dotty.tools.dotc.Driver.finish(Driver.scala:56)
at dotty.tools.dotc.Driver.doCompile(Driver.scala:36)
at dotty.tools.dotc.Driver.process(Driver.scala:195)
at dotty.tools.dotc.Driver.process(Driver.scala:163)
at dotty.tools.dotc.Driver.process(Driver.scala:175)
at dotty.tools.dotc.Driver.main(Driver.scala:205)
at dotty.tools.dotc.Main.main(Main.scala)
Caused by: java.lang.ClassNotFoundException: internal.Context
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:440)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:587)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
```
Compiler version
3.3.1-RC1-bin-20230518-4ffe5af-NIGHTLY 3.3.0-RC6 3.2.2 and previous (including 3.0 and 3.1 versions)
Minimized code
I was unable to minimize further.
Output (click arrow to expand)
The error disappears when the
EmptyArgsclass is moved fromContext.scalato a separate file.Expectation
Should compile with no errors, just like it does when
EmptyArgsis moved to a separate file.