Abstract class
-----
<?php

abstract class A {
    public function a() {}
    abstract public function b();
}
-----
array(
    0: Stmt_Class(
        type: 16
        name: A
        extends: null
        implements: array(
        )
        stmts: array(
            0: Stmt_ClassMethod(
                type: 1
                byRef: false
                name: a
                params: array(
                )
                returnType: null
                stmts: array(
                )
            )
            1: Stmt_ClassMethod(
                type: 17
                byRef: false
                name: b
                params: array(
                )
                returnType: null
                stmts: null
            )
        )
    )
)