Regression: inference fails to reject incompatible upper bounds

The following program erroneously compiles after JDK-8046685:

import java.util.List;

class Test {
<A2 extends A, A> A m(List<? super A2> a2) { return null; }
<B> B g(B b) { return null; }

void test() {
List<Integer> I = null;
String s = g(m(I));
}
}

This used to give the following error:

error: incompatible types: inference variable A2 has incompatible upper bounds String,B,Object,Integer,A
String s = g(m(I));
^
  where A2,A,B are type-variables:
    A2 extends A declared in method <A2,A>m(List<? super A2>)
    A extends Object declared in method <A2,A>m(List<? super A2>)
    B extends Object declared in method <B>g(B)
1 error