From cef807c92d488d51782a6e19a3b6aa89385948eb Mon Sep 17 00:00:00 2001
From: quinnj <quinn.jacobd@gmail.com>
Date: Thu, 4 Oct 2018 11:00:23 -0600
Subject: [PATCH] Define convert for DataValue from missing. Fixes
 https://github.com/JuliaData/Tables.jl/issues/25

---
 src/scalar/core.jl       | 1 +
 test/scalar/test_core.jl | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/src/scalar/core.jl b/src/scalar/core.jl
index 1e34946..a5eb47c 100644
--- a/src/scalar/core.jl
+++ b/src/scalar/core.jl
@@ -21,6 +21,7 @@ Base.eltype(::Type{DataValue{T}}) where {T} = T
 
 Base.convert(::Type{DataValue{T}}, x::DataValue{T}) where {T} = x
 Base.convert(::Type{DataValue}, x::DataValue) = x
+Base.convert(::Type{D}, ::Missing) where {D <: DataValue} = D()
 
 Base.convert(t::Type{DataValue{T}}, x::Any) where {T} = convert(t, convert(T, x))
 
diff --git a/test/scalar/test_core.jl b/test/scalar/test_core.jl
index c7c03d6..afcec20 100644
--- a/test/scalar/test_core.jl
+++ b/test/scalar/test_core.jl
@@ -248,4 +248,6 @@ io = IOBuffer()
 show(io, DataValue(enum_val_a))
 @test String(take!(io)) == "DataValue{TestEnum}(enum_val_a)"
 
+@test convert(DataValue{String}, missing) == DataValue{String}()
+
 end