TypeError typeassert for custom types
I don't understand the following behavior
a = [1,2,3]
a::Vector # works
d = Dict(0=>a)
typealias DictVector{K,V} Dict{K, Vector{V}}
d::DictVector # fails
the error is as follows
TypeError: typeassert: expected Dict{K,Array{V,1}}, got
Dict{Int64,Array{Int64,1}}
in include_string(::String, ::String) at loading.jl:441
in eval(::Module, ::Any) at boot.jl:234
in (::Atom.##65#68)() at eval.jl:40
in withpath(::Atom.##65#68, ::Void) at utils.jl:30
in withpath(::Function, ::Void) at eval.jl:46
in macro expansion at eval.jl:109 [inlined]
in (::Atom.##64#67{Dict{String,Any}})() at task.jl:60
however the vector itself is how typealias Vector{T} Array{T,1}
, so what is the crucial difference between the two cases?
Any clarification is much appreciated
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1 answer
You are right that you have to work. It looks like it was a bug in the old 0.5 type system. This is fixed in the upcoming version 0.6.
Here's a possible workaround for 0.5:
julia> typealias DictVector{K,V<:Vector} Dict{K,V}
Dict{K,V<:Array{T,1}}
julia> d::DictVector
Dict{Int64,Array{Int64,1}} with 1 entry:
0 => [1,2,3]
julia> isa(d, DictVector)
true
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