diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala | 13 | ||||
| -rw-r--r-- | test/files/neg/t5878.check | 13 | ||||
| -rw-r--r-- | test/files/neg/t5878.scala | 6 |
3 files changed, 30 insertions, 2 deletions
diff --git a/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala b/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala index 5f66cadbc9..e937589f54 100644 --- a/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala +++ b/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala @@ -78,13 +78,13 @@ abstract class ExtensionMethods extends Transform with TypingTransformers { } /** This method removes the `$this` argument from the parameter list a method. - * + * * A method may be a `PolyType`, in which case we tear out the `$this` and the class * type params from its nested `MethodType`. * It may be a `MethodType`, either with a curried parameter list in which the first argument * is a `$this` - we just return the rest of the list. * This means that the corresponding symbol was generated during `extmethods`. - * + * * It may also be a `MethodType` in which the `$this` does not appear in a curried parameter list. * The curried lists disappear during `uncurry`, and the methods may be duplicated afterwards, * for instance, during `specialize`. @@ -105,6 +105,14 @@ abstract class ExtensionMethods extends Transform with TypingTransformers { private val extensionDefs = mutable.Map[Symbol, mutable.ListBuffer[Tree]]() + def checkNonCyclic(pos: Position, seen: Set[Symbol], clazz: Symbol): Unit = + if (seen contains clazz) + unit.error(pos, "value class may not unbox to itself") + else { + val unboxed = erasure.underlyingOfValueClass(clazz).typeSymbol + if (unboxed.isDerivedValueClass) checkNonCyclic(pos, seen + clazz, unboxed) + } + def extensionMethInfo(extensionMeth: Symbol, origInfo: Type, clazz: Symbol): Type = { var newTypeParams = cloneSymbolsAtOwner(clazz.typeParams, extensionMeth) val thisParamType = appliedType(clazz.typeConstructor, newTypeParams map (_.tpeHK)) @@ -129,6 +137,7 @@ abstract class ExtensionMethods extends Transform with TypingTransformers { tree match { case Template(_, _, _) => if (currentOwner.isDerivedValueClass) { + checkNonCyclic(currentOwner.pos, Set(), currentOwner) extensionDefs(currentOwner.companionModule) = new mutable.ListBuffer[Tree] currentOwner.primaryConstructor.makeNotPrivate(NoSymbol) super.transform(tree) diff --git a/test/files/neg/t5878.check b/test/files/neg/t5878.check new file mode 100644 index 0000000000..50dba0d272 --- /dev/null +++ b/test/files/neg/t5878.check @@ -0,0 +1,13 @@ +t5878.scala:1: error: value class may not unbox to itself +case class Foo(x: Bar) extends AnyVal + ^ +t5878.scala:2: error: value class may not unbox to itself +case class Bar(x: Foo) extends AnyVal + ^ +t5878.scala:4: error: value class may not unbox to itself +class Foo1(val x: Bar1) extends AnyVal + ^ +t5878.scala:5: error: value class may not unbox to itself +class Bar1(val x: Foo1) extends AnyVal + ^ +four errors found diff --git a/test/files/neg/t5878.scala b/test/files/neg/t5878.scala new file mode 100644 index 0000000000..b4e33627ef --- /dev/null +++ b/test/files/neg/t5878.scala @@ -0,0 +1,6 @@ +case class Foo(x: Bar) extends AnyVal +case class Bar(x: Foo) extends AnyVal + +class Foo1(val x: Bar1) extends AnyVal +class Bar1(val x: Foo1) extends AnyVal + |