wartremover.warts.ImplicitParameter.scala Maven / Gradle / Ivy
package org.wartremover
package warts
object ImplicitParameter extends WartTraverser {
def apply(u: WartUniverse): u.Traverser = {
import u.universe._
implicit class TypeOps(self: Type) { // 2.10 compat
def typeArgs: List[Type] = self match {
case PolyType(args, _) => args.map(_.typeSignature)
case TypeRef(_, _, args) => args
case ExistentialType(_, u) => u.typeArgs
case _ => List.empty[Type]
}
}
def flatTypesFrom(t: Type): Set[Type] = Set(t) ++ t.typeArgs.flatMap(x => flatTypesFrom(x))
def isImplicitParamTypeInTparams(param: ValDef, tparamSymbols: Set[Symbol]) =
(flatTypesFrom(param.tpt.tpe) - param.tpt.tpe).exists { t =>
tparamSymbols.contains(t.typeSymbol)
}
new u.Traverser {
override def traverse(tree: Tree): Unit = {
tree match {
// Ignore trees marked by SuppressWarnings
case t if hasWartAnnotation(u)(t) =>
case DefDef(_, _, tparams, paramss, _, _) if !isSynthetic(u)(tree) && {
val parentTSymbols = if (tree.symbol.owner.isClass) {
val parentAbstractTSymbols = tree.symbol.owner.typeSignature.members.filter(_.isType).toList
tree.symbol.owner.asClass.typeParams ::: parentAbstractTSymbols
} else
Nil
val tsymbols = tparams.map(_.symbol) ::: parentTSymbols
def isManualImplicit(x: ValDef): Boolean =
x.symbol.isImplicit &&
!x.symbol.isSynthetic &&
!isImplicitParamTypeInTparams(x, tsymbols.toSet)
paramss.lastOption.fold(false)(_.exists(isManualImplicit))
} =>
error(u)(tree.pos, "Implicit parameters are disabled")
case _ =>
super.traverse(tree)
}
}
}
}
}