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/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Paul Phillips
*/
package scala.tools.nsc
package typechecker
/** This trait provides logic for assessing the validity of argument
* adaptations, such as tupling, unit-insertion, widening, etc. Such
* logic is spread around the compiler, without much ability on the
* part of the user to tighten the potentially dangerous bits.
*
* TODO: unifying/consolidating said logic under consistent management.
*
* @author Paul Phillips
*/
trait Adaptations {
self: Analyzer =>
import global._
import definitions._
trait Adaptation {
self: Typer =>
import runDefinitions._
def checkValidAdaptation(t: Tree, args: List[Tree]): Boolean = {
def applyArg = t match {
case Apply(_, arg :: Nil) => arg
case _ => EmptyTree
}
def callString = (
( if (t.symbol.isConstructor) "new " else "" ) +
( t.symbol.owner.decodedName ) +
( if (t.symbol.isConstructor || t.symbol.name == nme.apply) "" else "." + t.symbol.decodedName )
)
def sigString = t.symbol.owner.decodedName + (
if (t.symbol.isConstructor) t.symbol.signatureString
else "." + t.symbol.decodedName + t.symbol.signatureString
)
def givenString = if (args.isEmpty) "<none>" else args.mkString(", ")
def adaptedArgs = if (args.isEmpty) "(): Unit" else args.mkString("(", ", ", "): " + applyArg.tpe)
def adaptWarningMessage(msg: String, showAdaptation: Boolean = true) = msg +
"\n signature: " + sigString +
"\n given arguments: " + givenString +
(if (showAdaptation) "\n after adaptation: " + callString + "(" + adaptedArgs + ")" else "")
// A one-argument method accepting Object (which may look like "Any"
// at this point if the class is java defined) is a "leaky target" for
// which we should be especially reluctant to insert () or auto-tuple.
def isLeakyTarget = {
val oneArgObject = t.symbol.paramss match {
case (param :: Nil) :: Nil => ObjectClass isSubClass param.tpe.typeSymbol
case _ => false
}
// Unfortunately various "universal" methods and the manner in which
// they are used limits our ability to enforce anything sensible until
// an opt-in compiler option is given.
oneArgObject && !(
isStringAddition(t.symbol)
|| isArrowAssoc(t.symbol)
|| t.symbol.name == nme.equals_
|| t.symbol.name == nme.EQ
|| t.symbol.name == nme.NE
)
}
if (settings.noAdaptedArgs)
context.warning(t.pos, adaptWarningMessage("No automatic adaptation here: use explicit parentheses."))
else if (args.isEmpty) {
if (settings.future)
context.error(t.pos, adaptWarningMessage("Adaptation of argument list by inserting () has been removed.", showAdaptation = false))
else {
val msg = "Adaptation of argument list by inserting () is deprecated: " + (
if (isLeakyTarget) "leaky (Object-receiving) target makes this especially dangerous."
else "this is unlikely to be what you want.")
context.deprecationWarning(t.pos, t.symbol, adaptWarningMessage(msg), "2.11.0")
}
} else if (settings.warnAdaptedArgs)
context.warning(t.pos, adaptWarningMessage(
s"Adapting argument list by creating a ${args.size}-tuple: this may not be what you want.")
)
// return `true` if the adaptation should be kept
!(settings.noAdaptedArgs || (args.isEmpty && settings.future))
}
}
}
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