original.name="OpenRecord_Valid_2"
======
>>> main.whiley
final int Short = 3
final int Int = 4

type string is int[]
type char is int

type Primitive is (int x) where x == Short || x == Int

type Class is {string[] classes, string pkg}

type Any is Primitive | Class

type Unit is {int op, int offset}

type FieldIndex is {int op, string name, Class owner, int offset, Any type}

type Bytecode is Unit | FieldIndex

type Attribute is {string name, ...}

type CodeAttribute is {string name, Bytecode[] data}

function codeLength(Attribute a) -> null | int:
    if a is CodeAttribute:
        return |a.data|
    return null

public export method test() :
    Attribute attr = {name: "Code", data: [{op: 2, offset: 1}]}
    assume codeLength(attr) == 1
    attr = {name: "Blah"}
    assume codeLength(attr) == null

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