Scala Quill error when using infix

Question

I run into problem when using Quill 's infix operation .
Scala 2.12.4 Quill 2.3.3

import io.getquill._
val ctx = new SqlMirrorContext(PostgresDialect, SnakeCase)
import ctx._

// infix for custom DB operation
implicit class StringQuotes(left: String) {
  def equalTest(right: String): Quoted[Boolean] = quote {
    infix"$left = $right".as[Boolean]
  }
}

case class User(name: String)

object User {
  // normal usage 
  def filter1() = quote {
    query[User]
      .filter(
        user => user.name == "Cool"
      )
  }
  //using infix for custom operation
  def filter2() = quote {
    query[User]
      .filter(
        user => user.name equalTest "Cool"
      )
  }
}
//pass, and generates a valid SQL.
ctx.run(User.filter1())

// fail
ctx.run(User.filter2())

The error message is obscure:

java.util.NoSuchElementException: value user
..... too long to show
Error while emitting main.scala

It only indicate filter2 is cause, and doesn't say which line wrong.

Runnable code snippet at Scastie online editor https://scastie.scala-lang.org/superChing/haYVkGLDSlKsOhYlaPdO1w

Answer 1

It works without explicit return type Quoted[Boolean] in equalTest function :

def equalTest(right: String) = quote {
    infix"$left = $right".as[Boolean]
}