From 0bcb9e9169146e3f589c6c9f65cc4a5523b78120 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Sat, 3 Nov 2012 16:19:46 +0100 Subject: SI-6567 Warning for Option(implicitView(foo)) I've seen the reported problem before in the wild. It seems worthy of a special warning, so long as we advocate Option.apply as an alternative to `if (x == null) Some(x) else None`. It is behind -Xlint at the moment, an option that could do with some promotion. --- src/compiler/scala/tools/nsc/typechecker/RefChecks.scala | 11 ++++++++++- src/reflect/scala/reflect/internal/Definitions.scala | 10 ++++++---- 2 files changed, 16 insertions(+), 5 deletions(-) (limited to 'src') diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala index c04a8661b2..60bed95b9e 100644 --- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala +++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala @@ -1051,6 +1051,12 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans def apply(tp: Type) = mapOver(tp).normalize } + def checkImplicitViewOptionApply(pos: Position, fn: Tree, args: List[Tree]): Unit = if (settings.lint.value) (fn, args) match { + case (tap@TypeApply(fun, targs), List(view: ApplyImplicitView)) if fun.symbol == Option_apply => + unit.warning(pos, s"Suspicious application of an implicit view (${view.fun}) in the argument to Option.apply.") // SI-6567 + case _ => + } + def checkSensible(pos: Position, fn: Tree, args: List[Tree]) = fn match { case Select(qual, name @ (nme.EQ | nme.NE | nme.eq | nme.ne)) if args.length == 1 => def isReferenceOp = name == nme.eq || name == nme.ne @@ -1535,7 +1541,10 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans case Apply(fn, args) => // sensicality should be subsumed by the unreachability/exhaustivity/irrefutability analyses in the pattern matcher - if (!inPattern) checkSensible(tree.pos, fn, args) + if (!inPattern) { + checkImplicitViewOptionApply(tree.pos, fn, args) + checkSensible(tree.pos, fn, args) + } currentApplication = tree tree } diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala index ac1722f069..188078146a 100644 --- a/src/reflect/scala/reflect/internal/Definitions.scala +++ b/src/reflect/scala/reflect/internal/Definitions.scala @@ -540,10 +540,12 @@ trait Definitions extends api.StandardDefinitions { lazy val ScalaLongSignatureAnnotation = requiredClass[scala.reflect.ScalaLongSignature] // Option classes - lazy val OptionClass: ClassSymbol = requiredClass[Option[_]] - lazy val SomeClass: ClassSymbol = requiredClass[Some[_]] - lazy val NoneModule: ModuleSymbol = requiredModule[scala.None.type] - lazy val SomeModule: ModuleSymbol = requiredModule[scala.Some.type] + lazy val OptionClass: ClassSymbol = requiredClass[Option[_]] + lazy val OptionModule: ModuleSymbol = requiredModule[scala.Option.type] + lazy val Option_apply = getMemberMethod(OptionModule, nme.apply) + lazy val SomeClass: ClassSymbol = requiredClass[Some[_]] + lazy val NoneModule: ModuleSymbol = requiredModule[scala.None.type] + lazy val SomeModule: ModuleSymbol = requiredModule[scala.Some.type] def compilerTypeFromTag(tt: ApiUniverse # WeakTypeTag[_]): Type = tt.in(rootMirror).tpe def compilerSymbolFromTag(tt: ApiUniverse # WeakTypeTag[_]): Symbol = tt.in(rootMirror).tpe.typeSymbol -- cgit v1.2.3