From 90efa6bc35f0e4e1d37389af5a681836a03b68e5 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Wed, 5 Dec 2012 00:07:28 +0100 Subject: SI-3995 Exclude companions with an existential prefix. In `(qual: Q).apply(expr)` where `expr` must be implictily converted to a path dependent type `T` defined in `qual`, we were looking for companion implicits via a path prefixed by an existential skolem `_1`. These aren't much good to us, as when we try to feed them into `mkAttributedQualifer`, a crash rightly ensues. This commit excludes companions prefixed by an existentially bound path. --- .../scala/tools/nsc/typechecker/Implicits.scala | 6 +++--- test/files/neg/t3995.check | 6 ++++++ test/files/neg/t3995.scala | 25 ++++++++++++++++++++++ 3 files changed, 34 insertions(+), 3 deletions(-) create mode 100644 test/files/neg/t3995.check create mode 100644 test/files/neg/t3995.scala diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala index fc10f68454..68db812ad7 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala @@ -935,8 +935,8 @@ trait Implicits { * - for alias types and abstract types, we take instead the parts * - of their upper bounds. * @return For those parts that refer to classes with companion objects that - * can be accessed with unambiguous stable prefixes, the implicits infos - * which are members of these companion objects. + * can be accessed with unambiguous stable prefixes that are not existentially + * bound, the implicits infos which are members of these companion objects. */ private def companionImplicitMap(tp: Type): InfoMap = { @@ -952,7 +952,7 @@ trait Implicits { infoMap(sym) = List() // ambiguous prefix - ignore implicit members } case None => - if (pre.isStable) { + if (pre.isStable && !pre.typeSymbol.isExistentiallyBound) { val companion = companionSymbolOf(sym, context) companion.moduleClass match { case mc: ModuleClassSymbol => diff --git a/test/files/neg/t3995.check b/test/files/neg/t3995.check new file mode 100644 index 0000000000..844150a528 --- /dev/null +++ b/test/files/neg/t3995.check @@ -0,0 +1,6 @@ +t3995.scala:24: error: type mismatch; + found : String("") + required: _1.F0 where val _1: Lift + (new Lift).apply("") + ^ +one error found diff --git a/test/files/neg/t3995.scala b/test/files/neg/t3995.scala new file mode 100644 index 0000000000..8eb4698aaa --- /dev/null +++ b/test/files/neg/t3995.scala @@ -0,0 +1,25 @@ +class Lift { + def apply(f: F0) {} + + class F0 + object F0 { + implicit def f2f0(fn: String): F0 = ??? + } +} + +object Test { + val l = new Lift + val f = "" + + "": l.F0 // okay + + // fails trying to mkAttributedQualifier for pre = Skolem(_1 <: Lift with Singletom).F0 + // should this even have shown up in `companionImplicitMap`? It says that: + // + // "@return For those parts that refer to classes with companion objects that + // can be accessed with unambiguous stable prefixes, the implicits infos + // which are members of these companion objects." + // + // The skolem is stable, but it doen't seem much good to us + (new Lift).apply("") +} -- cgit v1.2.3