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author | Adriaan Moors <adriaan.moors@epfl.ch> | 2010-09-16 22:26:24 +0000 |
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committer | Adriaan Moors <adriaan.moors@epfl.ch> | 2010-09-16 22:26:24 +0000 |
commit | e557acb9a7d672c0635c3eaf9fe385adc41e5c86 (patch) | |
tree | d13db6639464acc57f0e44b4b3ef6f3e607ad403 /test/files/pos/depmet_implicit_norm_ret.scala | |
parent | ce223fe7abc47af712382a64404604e75f9f4d20 (diff) | |
download | scala-e557acb9a7d672c0635c3eaf9fe385adc41e5c86.tar.gz scala-e557acb9a7d672c0635c3eaf9fe385adc41e5c86.tar.bz2 scala-e557acb9a7d672c0635c3eaf9fe385adc41e5c86.zip |
part 2 of the dependent method refactoring: imp...
part 2 of the dependent method refactoring: improved interaction with
implicit search (needed for oopsla paper)
more to come in this area, see e.g. #3346 (stanford edsl stuff)
reopens #13, which wasn't fixed properly before imo, anyway (have a look at -Xprint:typer output before this commit: a type that's not expressible in surface syntax is inferred -- also removed duplicate test file)
closes #3731: co-evolve type alias type symbols when their rhs is
updated and they are referenced by type selections (see typemap)
review by odersky
Diffstat (limited to 'test/files/pos/depmet_implicit_norm_ret.scala')
-rw-r--r-- | test/files/pos/depmet_implicit_norm_ret.scala | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/test/files/pos/depmet_implicit_norm_ret.scala b/test/files/pos/depmet_implicit_norm_ret.scala new file mode 100644 index 0000000000..4cdb2931c6 --- /dev/null +++ b/test/files/pos/depmet_implicit_norm_ret.scala @@ -0,0 +1,29 @@ +object Test{ + def ?[S <: AnyRef](implicit w : S) : w.type = w + + // fallback, lower priority (overloading rules apply: pick alternative in subclass lowest in subtyping lattice) + class ZipWithDefault { + implicit def ZeroZipWith[S] = new ZipWith[S] { + type T = Stream[S] + } + } + + object ZipWith extends ZipWithDefault { + // def apply[S: ZipWith](s : S) = ?[ZipWith[S]].zipWith(s) // TODO: bug return type should be inferred + def apply[S](s : S)(implicit zw: ZipWith[S]): zw.T = zw.zipWith(s) + + implicit def SuccZipWith[S,R](implicit zWith : ZipWith[R]) = new ZipWith[S => R] { + type T = Stream[S] => zWith.T // dependent types replace the associated types functionality + } + } + + trait ZipWith[S] { + type T + def zipWith : S => T = error("") + } + + // bug: inferred return type = (Stream[A]) => java.lang.Object with Test.ZipWith[B]{type T = Stream[B]}#T + // this seems incompatible with vvvvvvvvvvvvvvvvvvvvvv -- #3731 + def map[A,B](f : A => B) /* : Stream[A] => Stream[B]*/ = ZipWith(f) + val tst: Stream[Int] = map{x: String => x.length}(Stream("a")) +}
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