# Possible vcat bug?

**URL:** https://discourse.julialang.org/t/possible-vcat-bug/15223
**Category:** Internals & Design
**Tags:** question
**Created:** [September 20, 2018, 11:17am UTC](https://discourse.julialang.org/t/possible-vcat-bug/15223 "2018-09-20T11:17:18Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [September 20, 2018, 11:17am UTC](https://discourse.julialang.org/t/possible-vcat-bug/15223/1 "2018-09-20T11:17:18Z")

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Asking before opening an issue, should I? MWE:

```julia
julia> VERSION
v"1.1.0-DEV.298"

julia> vcat(Nothing[], [missing], [1.0], [Int8(1)])
ERROR: MethodError: convert(::Type{Union{Missing, Nothing, Float64}}, ::Int8) is ambiguous. Candidates:
  convert(::Type{Union{Missing, T}}, x) where T in Base at missing.jl:43
  convert(::Type{Union{Nothing, T}}, x) where T in Base at some.jl:21
Possible fix, define
  convert(::Type{Union{Missing, Nothing}}, ::Any)

```

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<div class="post-metadata">

### Author: ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [September 21, 2018, 6:06am UTC](https://discourse.julialang.org/t/possible-vcat-bug/15223/2 "2018-09-21T06:06:54Z")

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[https://github.com/JuliaLang/julia/issues/29295](https://github.com/JuliaLang/julia/issues/29295)