Enum values are not properly reused due to underlyingArgument in macros

[Atry]

Compiler version

3.1.1

Minimized code

import scala.quoted.*

given staging.Compiler = staging.Compiler.make(getClass.getClassLoader)

def underlyingArgumentImpl[A](expr: Expr[A])(using Quotes, Type[A]) =
  import scala.quoted.quotes.reflect.*
  expr.asTerm.underlyingArgument.asExprOf[A]

inline def underlyingArgument[A](inline a: A): A = ${
  underlyingArgumentImpl('a)
}

val b: Boolean = staging.run[Boolean] {
  '{
    def f() = {
      enum E:
        case V
      underlyingArgument(E.V == E.V)
    }
    f()
  }
}

println(b)

https://scastie.scala-lang.org/82665kkpQ3KIBESu0jMnTg

Output

false

Expectation

true

[Atry]

If I replace expr.asTerm.underlyingArgument.asExprOf[A] with expr.asTerm.asExprOf[A], then the output would be true, as expected.

https://scastie.scala-lang.org/XuLYeLJ4TPmf8saom43maA

[Atry]

Note that the staging compiler is used to bypass the error "Cannot call macro method underlyingArgumentImpl defined in the same source file". This bug can be reproduced without the staging compiler.

[nicolasstucki]

It is unsafe to use the result of underlyingArgument in the generated code. The tree returned by this method is only meant to be analyzed.

The documentation should state this clearly.