From 411155176b7ee50d2d1c349de256ecc538a9bc41 Mon Sep 17 00:00:00 2001
From: Cameron Prybol <cjprybol@users.noreply.github.com>
Date: Wed, 11 Oct 2017 17:34:28 -0700
Subject: [PATCH] Restrict zero function types

Base only provides `zero(::Type{T}) where T<:Number`, not `zero(::Type{T}) where T`, and our method results in StackOverflows when called with `Any` when it should return an error. See https://github.com/JuliaData/DataFrames.jl/issues/1251
---
 src/Nulls.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Nulls.jl b/src/Nulls.jl
index a9eaa50..9b68a03 100644
--- a/src/Nulls.jl
+++ b/src/Nulls.jl
@@ -67,7 +67,7 @@ for f in (:(!), :(+), :(-), :(Base.identity), :(Base.zero),
     @eval $(f)(d::Null) = null
 end
 
-Base.zero(::Type{Union{T, Null}}) where {T} = zero(T)
+Base.zero(::Type{Union{T, Null}}) where {T <: Number} = zero(T)
 
 # Binary operators/functions
 for f in (:(+), :(-), :(*), :(/), :(^),