diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/Typers.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 70acb03584..c41b81aaf5 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -741,6 +741,26 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper case _ => } + /** + * Convert a SAM type to the corresponding FunctionType, + * extrapolating BoundedWildcardTypes in the process + * (no type precision is lost by the extrapolation, + * but this facilitates dealing with the types arising from Java's use-site variance). + */ + def samToFunctionType(tp: Type, sam: Symbol = NoSymbol): Type = { + val samSym = sam orElse samOf(tp) + + def correspondingFunctionSymbol = { + val numVparams = samSym.info.params.length + if (numVparams > definitions.MaxFunctionArity) NoSymbol + else FunctionClass(numVparams) + } + + if (samSym.exists && samSym.owner != correspondingFunctionSymbol) // don't treat Functions as SAMs + wildcardExtrapolation(normalize(tp memberInfo samSym)) + else NoType + } + /** Perform the following adaptations of expression, pattern or type `tree` wrt to * given mode `mode` and given prototype `pt`: * (-1) For expressions with annotated types, let AnnotationCheckers decide what to do @@ -824,7 +844,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper case Block(_, tree1) => tree1.symbol case _ => tree.symbol } - if (!meth.isConstructor && isFunctionType(pt)) { // (4.2) + if (!meth.isConstructor && (isFunctionType(pt) || samOf(pt).exists)) { // (4.2) debuglog(s"eta-expanding $tree: ${tree.tpe} to $pt") checkParamsConvertible(tree, tree.tpe) val tree0 = etaExpand(context.unit, tree, this) @@ -2838,7 +2858,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper * as `(a => a): Int => Int` should not (yet) get the sam treatment. */ val sam = - if (!settings.Xexperimental || pt.typeSymbol == FunctionSymbol) NoSymbol + if (pt.typeSymbol == FunctionSymbol) NoSymbol else samOf(pt) /* The SAM case comes first so that this works: @@ -2848,15 +2868,11 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper * Note that the arity of the sam must correspond to the arity of the function. */ val samViable = sam.exists && sameLength(sam.info.params, fun.vparams) + val ptNorm = if (samViable) samToFunctionType(pt, sam) else pt val (argpts, respt) = - if (samViable) { - val samInfo = pt memberInfo sam - (samInfo.paramTypes, samInfo.resultType) - } else { - pt baseType FunctionSymbol match { - case TypeRef(_, FunctionSymbol, args :+ res) => (args, res) - case _ => (fun.vparams map (_ => if (pt == ErrorType) ErrorType else NoType), WildcardType) - } + ptNorm baseType FunctionSymbol match { + case TypeRef(_, FunctionSymbol, args :+ res) => (args, res) + case _ => (fun.vparams map (_ => if (pt == ErrorType) ErrorType else NoType), WildcardType) } if (!FunctionSymbol.exists) |