anonymous given name does not include singleton term references

[rssh]

Minimized code

package x

trait Printer[T]:
  def print(t:T):String

extension[T](t:T)(using Printer[T])
  def print():String = summon[Printer[T]].print(t)

object A

object B

given Printer[A.type] with
   def print(a:A.type):String = "a"

given Printer[B.type] with
   def print(b:B.type):String = "b"



object Main {

  def main(args:Array[String]):Unit =
    System.out.println(B.print())

}

Output

[info] compiling 1 Scala source to /Users/rssh/tests/dotty/obj_extension/target/scala-3.0.0-RC1/classes ...
[error] -- [E161] Naming Error: /Users/rssh/tests/dotty/obj_extension/src/main/scala/x/Main.scala:16:6 
[error] 16 |given Printer[B.type] with
[error]    |^
[error]    |given_Printer_[ModuleClass]/T is already defined as object given_Printer_/T in /Users/rssh/tests/dotty/obj_extension/src/main/scala/x/Main.scala
[error] 17 |   def print(b:B.type):String = "b"
[error] -- [E008] Not Found Error: /Users/rssh/tests/dotty/obj_extension/src/main/scala/x/Main.scala:24:25 
[error] 24 |    System.out.println(B.print())
[error]    |                       ^^^^^^^
[error]    |value print is not a member of x.B[ModuleClass]/T.
[error]    |An extension method was tried, but could not be fully constructed:
[error]    |
[error]    |    <
[error]    |      <
[error]    |        <<x.print:([T/T](t: T)(using x$1: x.Printer/T[T])(): String/T)>[x.B.type]:
[error]    |          ((t: x.B.type)(using x$1: x.Printer/T[x.B.type])(): String/T)
[error]    |        >
[error]    |      (<x.B:x.B[ModuleClass]/T>):((using x$1: x.Printer/T[x.B.type])(): String/T)>
[error]    |    (
[error]    |      </* missing */summon[x.Printer/T[x.B.type]]:
[error]    |        <error no implicit values were found that match type x.Printer/T[x.B.type]>
[error]    |      >
[error]    |    ):
[error]    |      <error <
[error]    |      <
[error]    |        <<x.print:([T/T](t: T)(using x$1: x.Printer/T[T])(): String/T)>[x.B.type]:
[error]    |          ((t: x.B.type)(using x$1: x.Printer/T[x.B.type])(): String/T)
[error]    |        >
[error]    |      (<x.B:x.B[ModuleClass]/T>):((using x$1: x.Printer/T[x.B.type])(): String/T)>
[error]    |    (
[error]    |      </* missing */summon[x.Printer/T[x.B.type]]:
[error]    |        <error no implicit values were found that match type x.Printer/T[x.B.type]>
[error]    |      >
[error]    |    ):<error no implicit values were found that match type x.Printer/T[x.B.type]>> does not match type ?{ print: ? }>
[error]    |    >    failed with
[error]    |
[error]    |        no implicit argument of type x.Printer/T[x.B.type] was found for parameter x$1 of method print in package x/T
[error] two errors found

Expectation

Should be compiled and run.

[odersky]

That's as specified. Synthesized names are intended to be simple so that they can be written by the user. This means that they can clash in more intricate situations. In that case you have to supply your own names,

[rssh]

Hm, mb move this to "feature requests"?
Because from an ergonomic point of view, the developer should not care about details of name mangling.

[bishabosha]

names for anonymous givens are only generated using the parts of the type that refer to other types (so singleton term references are not considered)

This is probably to prevent name clashes between terms and types

source: http://dotty.epfl.ch/docs/reference/contextual/relationship-implicits.html#anonymous-given-instances
and also the implemented solution at https://github.com/lampepfl/dotty/blob/dd68bea73016d823ef84e751e7a5b45303a499bc/compiler/src/dotty/tools/dotc/ast/Desugar.scala#L1012