Can't get constructor of java defined class in reflect api #18694
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Labels
area:metaprogramming:reflection
Issues related to the quotes reflection API
itype:bug
itype:question
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goshacodes
added
itype:bug
stat:needs triage
nicolasstucki
added
itype:question
area:metaprogramming:reflection
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@goshacodes could you provide the implementation of the macro? |
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@nicolasstucki minimized example. Also I can try contribute this with a spree, want this fixed build.sbtlazy val root = (project in file("."))
.settings(
scalaVersion := "3.6.2",
name := "java_class",
scalacOptions ++= Seq(
"-explain",
"-Xcheck-macros"
)
)JavaClass.javapublic class JavaClass {
}main.scalaimport scala.annotation.experimental
@main
@experimental
def main(): Unit =
mock[JavaClass]Macro.scalaimport scala.annotation.experimental
import scala.quoted.{Expr, Quotes, Type}
@experimental
inline def mock[T]: T = ${mockMacro[T]}
@experimental
def mockMacro[T: Type](using quotes: Quotes): Expr[T] =
import quotes.reflect.*
val tree = TypeTree.of[T]
val parents =
List(
Select(
New(TypeIdent(tree.tpe.typeSymbol)),
tree.tpe.typeSymbol.primaryConstructor
).appliedToArgs(List('{()}.asTerm))
)
val sym = Symbol.newClass(
Symbol.spliceOwner,
"anon",
parents.map {
case term: Term => term.tpe
case tpt: TypeTree => tpt.tpe
},
decls = _ => Nil,
selfType = None
)
val cls = ClassDef(sym, parents, Nil)
Block(
List(cls),
Typed(Apply(Select(New(TypeIdent(sym)), sym.primaryConstructor), Nil), TypeTree.of[T])
).asExprOf[T]
Output[error] java.lang.AssertionError: assertion failed: private constructor JavaClass in class JavaClass in /Users/gosha/IdeaProjects/java_class/src/main/java/JavaClass.java accessed from constructor anon in class anon in /Users/gosha/IdeaProjects/java_class/src/main/scala/main.scala
[error] scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
[error] dotty.tools.dotc.transform.ExpandPrivate.ensurePrivateAccessible(ExpandPrivate.scala:88)
[error] dotty.tools.dotc.transform.ExpandPrivate.transformSelect(ExpandPrivate.scala:98)
[error] dotty.tools.dotc.transform.ExpandPrivate.transformSelect(ExpandPrivate.scala:97)
[error] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:636)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:245)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:295)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:471) |
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@jchyb Also tagging you. Nicolas seems not active on github currently |
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Yes, I recently took over some of Nicolas' responsibilities. Thank you for the minimization! I believe this might be getting fixed soon with #22104. I'll make sure it is in 3.6.4 (should be back portable to LTS). |
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Compiler version
3.3.0
Description
I'm trying to extend a java class using reflect api.
To create a symbol for a class I need parent, either TypeTree or Term. TypeTree is not working here, so I'am trying to get a constructor and apply nulls as arguments
Minimized code
When I'm trying to use
tpe.typeSymbol.primaryConstructorcompiler crushes with this:So instead of trying to use primary constructor, I am trying to use another public one and I got this one.
After it I am trying to pass there a () as argument and it gives me another error:
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