Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

tag generation fails weirdly for higher-kinded types #7686

scabug opened this issue Jul 22, 2013 · 1 comment


Copy link

commented Jul 22, 2013

import scala.reflect.runtime.universe._

object Test extends App {
  def test[B[_]](implicit tt: TypeTag[B[_]]) = ???
17:26 ~/Projects/210x/sandbox (2.10.x)$ s -Yreify-debug
reifying = Option[_]
universe = scala.reflect.runtime.`package`.universe
mirror = <empty>
ExistentialType(List(newTypeName("_$1")), TypeRef(ThisType(scala), scala.Option, List(TypeRef(NoPrefix, newTypeName("_$1"), List()))))
tough type: Option[_] (ExistentialType)
Sym def: type _$1 (type)
Sym def: value tt (value)
Locatable: method test (method) owned by object Test (module class) at Test
TypeRef(ThisType(scala), scala.Option, List(TypeRef(NoPrefix, newTypeName("_$1"), List())))
TypeRef(NoPrefix, newTypeName("_$1"), List())
Filling in: value tt (value)
TypeRef(SingleType(SingleType(SingleType(SingleType(SingleType(ThisType(<root>), scala), scala.reflect), scala.reflect.runtime), scala.reflect.runtime.package), newTermName("universe")), newTypeName("TypeTag"), List(ExistentialType(List(newTypeName("_$1")), TypeRef(NoPrefix, newTypeName("B"), List(TypeRef(NoPrefix, newTypeName("_$1"), List()))))))
SingleType(SingleType(SingleType(SingleType(SingleType(ThisType(<root>), scala), scala.reflect), scala.reflect.runtime), scala.reflect.runtime.package), newTermName("universe"))
SingleType(SingleType(SingleType(SingleType(ThisType(<root>), scala), scala.reflect), scala.reflect.runtime), scala.reflect.runtime.package)
SingleType(SingleType(SingleType(ThisType(<root>), scala), scala.reflect), scala.reflect.runtime)
SingleType(SingleType(ThisType(<root>), scala), scala.reflect)
SingleType(ThisType(<root>), scala)
Locatable: value universe (getter) owned by package package (package object class) at scala.reflect.runtime.package
Locatable: trait TypeTag (trait) owned by trait TypeTags (trait) at scala.reflect.api.TypeTags
ExistentialType(List(newTypeName("_$1")), TypeRef(NoPrefix, newTypeName("B"), List(TypeRef(NoPrefix, newTypeName("_$1"), List()))))
tough type: B[_] (ExistentialType)
TypeRef(NoPrefix, newTypeName("B"), List(TypeRef(NoPrefix, newTypeName("_$1"), List())))
splicing B[_$1]
launching implicit search for scala.reflect.runtime.`package`.universe.TypeTag[B[_$1]]
implicit search was fruitless
trying to splice as manifest
no manifest in scope
Test.scala:7: error: No TypeTag available for Option[_]
one error found

This comment has been minimized.

Copy link

commented Jul 22, 2013

@scabug scabug added the reflection label Apr 7, 2017

@scabug scabug added this to the Backlog milestone Apr 7, 2017

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
None yet
2 participants
You can’t perform that action at this time.