Immutable type incorrectly created

[tknopp]

This is from https://groups.google.com/forum/#!topic/julia-users/LIXG4TjUpDI
and it might not be a Julia bug.

The issue is in ImmutableArrays.jl where the convert function is able to create a type other than the passed one. Here is a reduced test case:

immutable Vec2{T}
    x::T
    y::T
end

Vec2(a::AbstractVector) = Vec2(ntuple(2,x->a[x])...)

import Base.convert
convert{T}(::Type{Vec2{T}},x::AbstractVector) = Vec2(x)   

immutable MyType
     m::Vec2{Float32}
end

println(MyType([3.0;4.0]))

This pasted in a REPL prints

MyType(Vec2{Float32}(0.0f0,2.125f0))

Might it be able to detect when MyType is constructed the it got passed a Vec2{Float64}?

[JeffBezanson]

Seems it gets checked if MyType is mutable, and not if it is immutable. That seems like a bug.