[julia-users] "Constructor methods" for typealiases, why does this code not work in v0.4, but does in v0.5?

[Patrick Kofod Mogensen]

Hello,

We recently did some changes in Optim.jl, that unfortunately broke a line 
in DSGE.jl. I was actually unaware that OptimizationTrace was exported, so 
I didn't think about deprecating it. After Tony Kelman pointed this out to 
me, I tried to make a fix. Basically we have a typealias OptimizationTrace 
for Vector{OptimizationState{T}} where T<:Optimizer . I thought I could 
simply create a OptimizationTrace{T<:Optimizer}(method::T) = 
Vector{OptimizationState{T}() method to resolve the change in syntax, but 
the following doesn't work on v0.4

abstract Optimizer

immutable NelderMead <: Optimizer
end

immutable OptimizationState{T <: Optimizer}
                  iteration::Int
                  value::Float64
                  g_norm::Float64
                  metadata::Dict
              end

typealias OptimizationTrace{T} Vector{OptimizationState{T}}

OptimizationTrace{T<:Optimizer}(method::T) = Vector{OptimizationState{T}}()
OptimizationTrace(NelderMead())


Is there a way to define a similar method on v0.4? 

Best,
Patrick