Regression: separate compilation causes crash in wildcards inference logic

Steps to reproduce:

//Foo.java
interface Foo<X extends Number> {
    void m(X x);
}

class FooLib {
    void m(Foo<?> uf) { }
}

//Test.java
class Test {
    void test(FooLib fl) {
        fl.m(x->{});
    }
}

javac Foo.java
javac Test.java