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scalamonadsmonad-transformers

Type EnvT can not be found

I have the following code that does not compiled:

trait DbSetup[F[_]] {

  type EnvT[A] = OptionT[F, A]

  def system: EnvT[Env]

  def user: EnvT[String]

  def password: EnvT[String]

  def address: EnvT[String]

}

object DbSetup {

  def read[F[_]: Monad](s: DbSetup[F]): EnvT[Configuration] = ???

}

the compiler complains: 

not found: type EnvT
[error]   def read[F[_]: Monad](s: DbSetup[F]): EnvT[Configuration] = ???
[error]                                         ^
[error] one error found
[error] (Compile / compileIncremental) Compilation failed

How to import the type EnvT into the object scope?

Solution

  • Try

    def read[F[_]: Monad](s: DbSetup[F]): s.EnvT[Configuration] = ???