Why can't diamond infer types on anonymous inner classes?

Question

In Java 7 and later, diamond can be used to infer types on normally like so without an issue:

List list = new ArrayList<>();

Answer 1

In short, the <> does little to infer types, it turns off the warning you would get without it.

EDIT: As @Natix points out it does some checking.

List ints = new ArrayList<>();
List copy = new ArrayList<>(ints);

produces a compilation error

Error:Error:line (42)error: incompatible types
required: List
found:    ArrayList

As you can see the <> is taking the type of the argument, not inferring the type from the type of copy