Bug when using Union{Something, Missing} as type parameter

[meggart]

The following behavior seems to be a bug:

    struct S{T1, T2, T3}
    tair::T1
    country::T2
    lon::T3
end
s = S{Union{Float32,Missing},Union{Int32,Missing},Float64}(1.0,1,1.0)
s

returns:

S{Union{Missing, Float32},Union{Missing, Int32},Float64}(1.0f0, missing, 1.0)

and this even segfaults when accessing the second field:

using Dates
struct S2{T1, T2, T3,T4,T5}
                  tair::T1
                  country::T2
                  lon::T3
                  lat::T4
                  time::T5
end
s = S2{Union{Float32,Missing},Union{Int32,Missing},Float64,Float64,Date}(1.0,1,1.0,1.0,Date(2000))
s.country

I tried this on 0.7 as well as on JuliaBox 1.0. Is there a way to avoid this?

Versioninfo:

Julia Version 1.0.0
Commit 5d4eaca0c9 (2018-08-08 20:58 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Xeon(R) CPU E5-2673 v4 @ 2.30GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.0 (ORCJIT, broadwell)
Environment:
  JULIABOX = true
  JULIA_PKG_SERVER = https://pkg.juliacomputing.com
  JULIA = /opt/julia-0.6/bin/julia
  JULIA_KERNELS = ['julia-0.5', 'julia-0.6', 'julia-1.0']
  JULIABOX_ROLE = 

[tomaklutfu]

Is it solved by PR #29722 ?

[meggart]

Yes, this works on nightly, sorry for the noise

[StefanKarpinski]

No worries, thanks for reporting!