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author | Samuel Gruetter <samuel.gruetter@epfl.ch> | 2014-03-12 22:44:33 +0100 |
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committer | Samuel Gruetter <samuel.gruetter@epfl.ch> | 2014-03-12 22:44:33 +0100 |
commit | 9ef5f6817688f814a3450126aa7383b0928e80a0 (patch) | |
tree | 5727a2f7f7fd665cefdb312af2785c692f04377c /tests/untried/pos/t3177.scala | |
parent | 194be919664447631ba55446eb4874979c908d27 (diff) | |
download | dotty-9ef5f6817688f814a3450126aa7383b0928e80a0.tar.gz dotty-9ef5f6817688f814a3450126aa7383b0928e80a0.tar.bz2 dotty-9ef5f6817688f814a3450126aa7383b0928e80a0.zip |
add tests from scala/test/files/{pos,neg}
with explicit Unit return type
Diffstat (limited to 'tests/untried/pos/t3177.scala')
-rw-r--r-- | tests/untried/pos/t3177.scala | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/tests/untried/pos/t3177.scala b/tests/untried/pos/t3177.scala new file mode 100644 index 000000000..9b850966d --- /dev/null +++ b/tests/untried/pos/t3177.scala @@ -0,0 +1,39 @@ +trait InvariantFunctor[F[_]] { + def xmap[A, B](ma: F[A], f: A => B, g: B => A): F[B] +} + +object InvariantFunctor { + import Endo._ + + implicit val EndoInvariantFunctor = new InvariantFunctor[Endo] { + def xmap[A, B](ma: Endo[A], f: A => B, g: B => A): Endo[B] = (b: B) => f(ma(g(b))) + } + + // The definition about fails with: + // anon-type.scala:9: error: not found: value b + // def xmap[A, B](ma: Endo[A], f: A => B, g: B => A): Endo[B] = (b: B) => f(ma(g(b))) + // ^ + // anon-type.scala:8: error: not found: type $anon + // implicit val EndoInvariantFunctor = new InvariantFunctor[Endo] { + // ^ + + + // These both work: + // implicit val EndoInvariantFunctorAscribed: InvariantFunctor[Endo] = new InvariantFunctor[Endo] { + // def xmap[A, B](ma: Endo[A], f: A => B, g: B => A): Endo[B] = (b: B) => f(ma(g(b))) + // } + // + // implicit val EndoInvariantFunctorStubbed = new InvariantFunctor[Endo] { + // def xmap[A, B](ma: Endo[A], f: A => B, g: B => A): Endo[B] = error("stub") + // } +} + +trait Endo[X] + +object Endo { + implicit def EndoTo[A](f: A => A): Endo[A] = new Endo[A] { + def apply(a: A) = f(a) + } + + implicit def EndoFrom[A](e: Endo[A]): A => A = e.apply(_) +} |