Strange error message

pathological_unique.jl

import Base: unique, hash

immutable Prehashed
    hash::Uint
end
hash(x::Prehashed) = x.hash

function unique{T}(A::AbstractArray{T,2}, dim::Int)
    hashes = zeros(Uint, size(A, 1))

    # Compute hash for each row
    for j = 1:size(A, 1), i = 1:size(A, 2)
       hashes[j] = bitmix(hashes[j], hash(A[j, i]))
    end

    # Collect index of first row for each hash
    uniquerow = Array(Int, size(A, 1))
    firstrow = Dict{Prehashed,Int}()
    for j = 1:size(A, 1)
        uniquerow[j] = get!(firstrow, Prehashed(hashes[j]), j)
    end
    uniquerows = collect(values(firstrow))

    # println(typeof((ifelse(true,sort(uniquerows),1:size(A,1)), 1:size(A,2))))
    A[ifelse(true,sort(uniquerows),1:size(A,1)), 1:size(A,2)]
end

sz = 10000
A = rand(div(sz*100, 2), div(sz, 100))
A = A[shuffle!(repmat(1:div(sz*100, 2), 2)), :]

unique(A, 1)
println("ran once")

unique(A, 1)
println("does not get here")