Closed
Description
Very similar to #2377 (which is fixed).
Java file:
public final class A {
public static final class T { }
public static final class Inner {
public static final class T { }
public T newT() { return null; }
}
}Scala file:
class C {
val i = new A.Inner()
println(i.newT())
}Mixed compilation:
lucmac:sandbox luc$ scalac A.java Test.scala
A.java:5: error: reference to T is ambiguous;
it is both defined in object A and imported subsequently by
import Inner._
public T newT() { return null; }
^
one error found
the reason is Scalac's desugaring which introduces an import:
object A {
class T
object Inner {
class T
}
class Inner {
import Inner._
def newT1(): T = null // reference to T is ambiguous
}
}
class Aseparate compilation (java first) works
Even worse: instead of an ambiguity, the Scala compiler resolves types in Java signatures incorrectly:
A.java
public class A {
public static class P {
public static class T { public void f() { } }
}
public static class T { public void g() { } }
public static class Inner extends P {
public class Deeper {
public void foo(T t) { t.f(); }
}
}
}Test.scala
object Test extends App {
val i = new A.Inner()
val j = new i.Deeper()
println(j.foo(new A.T())) // compiles in mixed compilation (it should not)
}Mixed compilation works, but runtime fails. Seperate compilation fails (correctly):
lucmac:sandbox luc$ scalac A.java Test.scala
lucmac:sandbox luc$ javac A.java
lucmac:sandbox luc$ scala Test
java.lang.NoSuchMethodError: A$Inner$Deeper.foo(LA$T;)V
at Test$.delayedEndpoint$Test$1(Test.scala:5)
lucmac:sandbox luc$ scalac Test.scala
Test.scala:5: error: type mismatch;
found : A.T
required: A.P.T
println(j.foo(new A.T()))
^
one error found
In this example, the Scala compiler does not inject any import Inner._. The Java parser checks if there are any statics in the class. If not, it doesn't add the import. This is wrong because statics may be inherited.