Sammy gets confused with Java classes

[scabug]

A.java

public class A {
  public B b() { return null; }
}

B.java

public abstract class B {
  public abstract int m();
}

Test.scala

class T {
  def f(a: A) = g(a.b)
  def g(b: => B) = null
}

Compiling:

$ javac A.java B.java
$ scalac -Xexperimental A.scala -Xprint:typer
A.scala:2: error: type mismatch;
 found   : B
 required: Int
  def f(a: A) = g(a.b)
                    ^
[[syntax trees at end of                     typer]] // A.scala
package <empty> {
  class T extends scala.AnyRef {
    def <init>(): T = {
      T.super.<init>();
      ()
    };
    def <f: error>(a: A): <error> = T.this.g(a.b);
    def g(b: => B): Null = null
  }
}

one error found

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-9489?orig=1
Reporter: @lrytz
Affected Versions: 2.11.7
See #9178

[scabug]

@lrytz said:
This was found while trying to bootstrap with sammy enabled, see scala/scala#4767

[scabug]

@retronym said:
Duplicate of #9178

[adriaanm]

scala/scala#7660 now eta-expands again in this situation, but we get a warning