org.wartremover.warts.ForbidInference.scala Maven / Gradle / Ivy
package org.wartremover
package warts
trait ForbidInference[T] extends WartTraverser {
def applyForbidden(u: WartUniverse)(implicit t: u.TypeTag[T]): u.Traverser = {
import u.universe._
val CanEqualName = TermName("canEqual")
val EqualsName = TermName("equals")
val ProductElementName = TermName("productElement")
val ProductIteratorName = TermName("productIterator")
// since Scala 2.13 https://github.com/scala/scala/commit/efc48213073ce5e68a7fd7dc9820610eccdeb9f7
val ProductElementNameName = TermName("productElementName")
val tSymbol = typeOf[T].typeSymbol
// Scala compiler inserts stuff like "extends AnyRef with Serializable"
// This method filters those out.
def explicitParents(parents: List[Tree]): List[Tree] = parents.collect {
case tpt @ TypeTree() if !wasInferred(u)(tpt) =>
tpt
}
new u.Traverser {
override def traverse(tree: Tree): Unit = {
val synthetic = isSynthetic(u)(tree)
def error(tpe: Type) =
ForbidInference.this.error(u)(tree.pos, s"Inferred type containing ${tSymbol.name}: $tpe")
tree match {
// Ignore trees marked by SuppressWarnings
case t if hasWartAnnotation(u)(t) =>
case tpt @ TypeTree() if wasInferred(u)(tpt) && tpt.tpe.contains(tSymbol) =>
tpt.tpe match {
// Ignore existential types, they supposedly contain "any"
case ExistentialType(_, _) =>
case _ =>
error(tpt.tpe)
}
// Ignore case classes generated methods
case ModuleDef(_, _, Template((parents, self, statements))) =>
explicitParents(parents).foreach(traverse)
traverse(self)
statements.foreach(traverse)
case ClassDef(_, _, _, Template((parents, self, statements))) if synthetic =>
explicitParents(parents).foreach(traverse)
traverse(self)
statements.foreach(traverse)
case ClassDef(_, className, _, Template((_, self, statements))) if isAnonymousFunctionName(u)(className) =>
// https://github.com/wartremover/wartremover/issues/294
traverse(self)
statements.foreach(traverse)
case DefDef(_, CanEqualName | EqualsName | ProductElementName | ProductIteratorName, _, _, _, _)
if synthetic =>
case _ =>
super.traverse(tree)
}
}
}
}
}