This code stopped compiling after the fix for JDK-8078093:

import java.util.ArrayList;
import java.util.Collection;

public class Foo {
    static <T> T foo(Class<T> c, Collection<? super T> baz) {
	return null;
    }

    static void bar(String c) {

    }

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
	// this works
	bar(foo(String.class, new ArrayList<String>()));

	// this works with a warning
	String s = foo(String.class, new ArrayList());
	bar(s);

	// this causes an error on JDK9
	bar(foo(String.class, new ArrayList()));
    }
}

Moreover, the error issued is weird-looking:

Foo.java:23: error: method bar in class Foo cannot be applied to given types;
                bar(foo(String.class, new ArrayList()));
                ^
  required: String
  found: String
  reason: argument mismatch; Object cannot be converted to String
1 error