Odd behavior with type inference

While constructing the FilteredCollection class, I ran into the following
oddity with type inference. The following class fails to compile (using
javac 1.6.0_20):

import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

public class Oddity<C> implements Iterable<C>
{
    public Iterator<C> iterator()
    {
        return null;
    }

    public static void main(String[] args)
    {
        List list = Arrays.asList(1, "a", false);
        for (String s : getOddity(list, String.class)) // ******
        {
        }
    }

    public static<T,C> Iterable<C> getOddity(Collection<T> coll, Class<C>
clazz)
    {
        return null;
    }
}

The error, at the starred line, is

    incompatible types
    found : java.lang.Object
    required: java.lang.String

That is, it looks as if the inference that getOddity should return an
Iterable<String> fails.

However, it works perfectly if the declaration of "list" in the previous
line is changed to

    List<?> list

What's the deal here? Does the presence of a raw type interfere with type
inference?