Segmentation fault

[ivarne]

On the latest julia build I get this:

               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http:https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" to list help topics
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.2.0-prerelease+3619
 _/ |\__'_|_|_|\__'_|  |  Commit 57a04d4* 2013-09-04 05:25:04 UTC
|__/                   |  x86_64-apple-darwin12.4.0

julia> abstract c

julia> type a
       a::Int64
       end

julia> type b
       a::Int64
       end

julia> function d(a::c)
       print(a.a)
       end
# methods for generic function d
d(a::c) at none:2

julia> d(a(5))
Segmentation fault: 11

Should this code work, and give me a function d that works on both a and b? My impression is that it should at least not segfault, and jeff usually fix these issues really fast.

[kmsquire]

More minimal version:

julia> type a
         a
       end

julia> a(5)
Segmentation fault (core dumped)

You probably shouldn't have the type and variable be the same name, but it shouldn't segfault.

[kmsquire]

Also, if you want types a and b to be subtypes of c, you should specify them as such:

abstract C

type A <: C
   n::Int64
end

type B <: C
   n::Int64
end

d(a::C) = print(a.n)

julia> d(A(5))
5

As a convention, types in Julia also have capital letters, so they can be distinguished more easily from variables.

[ivarne]

Thank you for pointing out the dump part of the issue. I did not remember to add the <: c when I retyped the example after rebuilding julia. Using capital letters is definitely a good convention, but as the variable naming suggest I was just using the alphabet and julia does not enforce that convention.

[kmsquire]

Yep, just a convention! It also might explain why this issue hasn't been noticed before.