Type argument inference crashed

[cushon]

public class CrashRepro {
  interface Iterator<E> {}

  interface CheckedIterator<T, X extends Exception> {}

  interface CheckedFunction<F, T, X extends Exception> {
    T apply(F input) throws X;
  }

  <F, T, X extends Exception> CheckedIterator<T, X> transform(
      Iterator<? extends F> fromIterator,
      CheckedFunction<? super F, ? extends T, ? extends X> function) {
    throw new UnsupportedOperationException();
  }

  interface Foo {
    Bar toBar();
  }

  interface Bar {}

  CheckedIterator<Bar, ?> run(Iterator<Foo> rows) {
    return transform(rows, row -> row.toBar());
  }
}

$ ~/checker-framework-4.0.0/checker/bin/javac -processor nullness CrashRepro.java
CrashRepro.java:23: error: [type.argument.inference.crashed] Type argument inference crashed for CrashRepro.transform
    return transform(rows, row -> row.toBar());
                    ^
  error: An exception occurred: class org.checkerframework.framework.util.typeinference8.types.InferenceType cannot be cast to class org.checkerframework.framework.util.typeinference8.types.UseOfVariable (org.checkerframework.framework.util.typeinference8.types.InferenceType and org.checkerframework.framework.util.typeinference8.types.UseOfVariable are in unnamed module of loader java.net.URLClassLoader @35fb3008)
CrashRepro.java:23: error: [type.argument.inference.crashed] Type argument inference crashed for CrashRepro.transform
    return transform(rows, row -> row.toBar());
                    ^
  error: An exception occurred: class org.checkerframework.framework.util.typeinference8.types.InferenceType cannot be cast to class org.checkerframework.framework.util.typeinference8.types.UseOfVariable (org.checkerframework.framework.util.typeinference8.types.InferenceType and org.checkerframework.framework.util.typeinference8.types.UseOfVariable are in unnamed module of loader java.net.URLClassLoader @35fb3008)
2 errors