parameterized java class with protected constructor incorrectly fails, then issues misleading message

[scabug]

// J.java
package foo;

public class J<M> { protected J(M m) { } }

// S.scala
package bar

class SC1 extends foo.J("")
class SC2 extends foo.J[String]("")

% scalac -d out -cp out S.scala 
S.scala:3: error: constructor J in class J cannot be accessed in package bar
 Access to protected constructor J not permitted because
 enclosing package bar is not a subclass of 
 class J in package foo where target is defined
class SC1 extends foo.J("")
          ^
one error found

Compiles in 2.8, regressed somewhere between 2.8 and 2.9. The fact that the type parameter is not inferred is not that big a deal by itself, but it is made much worse by the error message.

Notes: if S and J are in the same package, it compiles. If J is not parameterized, it compiles. If J is instead the equivalent scala class with a protected[foo] constructor, it compiles.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-6617?orig=1
Reporter: @paulp

[scabug]

@khernyo said (edited on Sep 12, 2015 5:35:40 PM UTC):
I believe this doesn't even need a java class to reproduce:

// A.scala
class A[M] protected(m: M)
class B extends A("a")

$ scalac A.scala 
A.scala:4: error: constructor A in class A cannot be accessed in package <empty>
 Access to protected constructor A not permitted because
 enclosing package <empty> is not a subclass of
 class A where target is defined
class B extends A("a")
                ^
one error found

This compiles in 2.8, but not later. It doesn't compile in current dotty either (same error message). On the other hand, specifying the type parameter makes it compile in all of them.

[som-snytt]

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