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author | Jason Zaugg <jzaugg@gmail.com> | 2013-06-11 10:56:48 -0400 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2013-06-19 22:48:38 +0200 |
commit | e7ac254349e56678824ade3027bca3908882e291 (patch) | |
tree | 9b7828b21d418f2ee8830cb07432048c72dea13d | |
parent | a54d86b5508630a4815ca7f6ca3d5f05b74b1d9f (diff) | |
download | scala-e7ac254349e56678824ade3027bca3908882e291.tar.gz scala-e7ac254349e56678824ade3027bca3908882e291.tar.bz2 scala-e7ac254349e56678824ade3027bca3908882e291.zip |
SI-7571 Allow nesting of anonymous classes in value classes
5d9cde105e added deep prohibition of nested classes within
a value class. This has the undesirable side effect of
prohibiting partial functions literals in method bodies
of a value class.
The intention of that prohibition was to avoid problems
in code using Type Tests, such as:
class C(val inner: A) extends AnyVal {
class D
}
def foo(a: Any, other: C) = a match { case _ : other.D }
Here, the pattern usually checks that `a.$outer == other`.
But that is incongruent with the way that `other` is erased
to `A`.
However, not all nested classes could lead us into this trap.
This commit slightly relaxes the restriction to allow anonymous
classes, which can't appear in a type test.
The test shows that the translation generates working code.
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 4 | ||||
-rw-r--r-- | test/files/neg/valueclasses-impl-restrictions.check | 8 | ||||
-rw-r--r-- | test/files/neg/valueclasses-impl-restrictions.scala | 4 | ||||
-rw-r--r-- | test/files/run/t7571.scala | 12 |
4 files changed, 19 insertions, 9 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 29cd3d4bfa..ed2963fb0f 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -1455,8 +1455,8 @@ trait Typers extends Modes with Adaptations with Tags { implRestriction(tree, "nested object") //see https://issues.scala-lang.org/browse/SI-6444 //see https://issues.scala-lang.org/browse/SI-6463 - case _: ClassDef => - implRestriction(tree, "nested class") + case cd: ClassDef if !cd.symbol.isAnonymousClass => // Don't warn about partial functions, etc. SI-7571 + implRestriction(tree, "nested class") // avoiding Type Tests that might check the $outer pointer. case Select(sup @ Super(qual, mix), selector) if selector != nme.CONSTRUCTOR && qual.symbol == clazz && mix != tpnme.EMPTY => //see https://issues.scala-lang.org/browse/SI-6483 implRestriction(sup, "qualified super reference") diff --git a/test/files/neg/valueclasses-impl-restrictions.check b/test/files/neg/valueclasses-impl-restrictions.check index 63924493aa..0af9173f74 100644 --- a/test/files/neg/valueclasses-impl-restrictions.check +++ b/test/files/neg/valueclasses-impl-restrictions.check @@ -6,12 +6,8 @@ valueclasses-impl-restrictions.scala:9: error: implementation restriction: neste This restriction is planned to be removed in subsequent releases. trait I2 { ^ -valueclasses-impl-restrictions.scala:15: error: implementation restriction: nested class is not allowed in value class -This restriction is planned to be removed in subsequent releases. - val i2 = new I2 { val q = x.s } - ^ -valueclasses-impl-restrictions.scala:21: error: implementation restriction: nested class is not allowed in value class +valueclasses-impl-restrictions.scala:23: error: implementation restriction: nested class is not allowed in value class This restriction is planned to be removed in subsequent releases. private[this] class I2(val q: String) ^ -four errors found +three errors found diff --git a/test/files/neg/valueclasses-impl-restrictions.scala b/test/files/neg/valueclasses-impl-restrictions.scala index 137f3f854c..f0577a94aa 100644 --- a/test/files/neg/valueclasses-impl-restrictions.scala +++ b/test/files/neg/valueclasses-impl-restrictions.scala @@ -12,8 +12,10 @@ class X1(val s: String) extends AnyVal { } def y(x: X1) = { - val i2 = new I2 { val q = x.s } + val i2 = new I2 { val q = x.s } // allowed as of SI-7571 i2.z + + { case x => x } : PartialFunction[Int, Int] // allowed } } diff --git a/test/files/run/t7571.scala b/test/files/run/t7571.scala new file mode 100644 index 0000000000..00b9695168 --- /dev/null +++ b/test/files/run/t7571.scala @@ -0,0 +1,12 @@ +class Foo(val a: Int) extends AnyVal { + def foo = { {case x => x + a}: PartialFunction[Int, Int]} + + def bar = (new {}).toString +} + +object Test extends App { + val x = new Foo(1).foo.apply(2) + assert(x == 3, x) + val s = new Foo(1).bar + assert(s.nonEmpty, s) +} |