Fixed-length array yields invalid Java code

[mthmulders]

Given a small input file, sample.tt:

const MY_CONSTANT = 42;
typedef long MyLongs[MY_CONSTANT];
struct MyStructure {
     MyLongs myLongs;
};

Invoking Treetop with: bundle exec xdrgen sample.tt -o generated -l java -n generated, it generates this Java source file:

// Automatically generated by xdrgen 
// DO NOT EDIT or your changes may be overwritten

package generated;


import java.io.IOException;

// === xdr source ============================================================

//  typedef long MyLongs[MY_CONSTANT];

//  ===========================================================================
public class MyLongs  {
  private Long[] MyLongs;
  public Long[] getMyLongs() {
    return this.MyLongs;
  }
  public void setMyLongs(Long[] value) {
    this.MyLongs = value;
  }
  public static void encode(XdrDataOutputStream stream, MyLongs  encodedMyLongs) throws IOException {
  int MyLongssize = encodedMyLongs.getMyLongs().length;
  for (int i = 0; i < MyLongssize; i++) {
    stream.writeLong(encodedMyLongs.MyLongs[i]);
  }
  }
  public static MyLongs decode(XdrDataInputStream stream) throws IOException {
    MyLongs decodedMyLongs = new MyLongs();
  int MyLongssize = MY_CONSTANT;
  decodedMyLongs.MyLongs = new Long[MyLongssize];
  for (int i = 0; i < MyLongssize; i++) {
    decodedMyLongs.MyLongs[i] = stream.readLong();
  }
    return decodedMyLongs;
  }
}

This code does not compile:

generated/MyLongs.java:31: error: cannot find symbol
  int MyLongssize = MY_CONSTANT;
                    ^
  symbol:   variable MY_CONSTANT
  location: class MyLongs
1 error

I've tried changing the decode_member method in java.rb to read

out.puts "int #{member.name}size = #{member.declaration.resolved_size};"

But that yields an error:

NameError: undefined local variable or method `root' for #<Xdrgen::AST::FixedSize:0x00007fb36a3845d0>
  /path/to/xdrgen/lib/xdrgen/ast/fixed_size.rb:10:in `resolved_size'
  /path/to/xdrgen/lib/xdrgen/ast/declarations/array.rb:5:in `resolved_size'
  /path/to/xdrgen/lib/xdrgen/generators/java.rb:L413:in `decode_member'

I have no clue how to fix this. Any ideas?