Scala 2.11宏 - 解析JDBC行到案例类

Question

我试图为我的Play Framework项目制作一个宏（2.3.7）。我试图将anorm Row映射到案例类变得容易。当我尝试编译附加的代码时，我得到以下异常：

[error] ***:15: exception    during macro expansion:
[error] java.util.NoSuchElementException: None.get
[error]     at scala.None$.get(Option.scala:322)
[error]     at scala.None$.get(Option.scala:320)
[error]     at ***.ModelMacros$.reads(ModelMacros.scala:29)

import anorm._

import scala.reflect.macros.whitebox
import scala.language.experimental.macros

object ModelMacros {
  implicit def sqlMapper[T]: Row => T = macro reads[T]

  def reads[T: c.WeakTypeTag](c: whitebox.Context): c.Expr[Row => T] = {
    import c.universe._

    val t = weakTypeOf[T]
    val companion = t.typeSymbol.companion

    val fields = t.declarations.collectFirst {
      case m: MethodSymbol if m.isPrimaryConstructor ⇒ m
    }.get.paramLists.head

    val fromMapParams = fields.map { field =>
      val name = field.name.toTermName
      val decoded = name.decodedName.toString
      val returnType = t.decl(name).typeSignature

      val fixedName = camelToUnderscores(decoded)

      q"row[$returnType]($fixedName)"
    }

    c.Expr[Row => T] {
      q"""
        { row => $companion(..$fromMapParams) }
      """
    }
  }
}

我不明白如何使通用T适当地反映出来。任何帮助将不胜感激。谢谢！