Support zero et al on ::Type{Missing}

halleysfifthinc · Mar 10, 2019 · d2a54ca · d2a54ca
1 parent 60457de
commit d2a54ca
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diff --git a/base/missing.jl b/base/missing.jl
@@ -83,6 +83,7 @@ for f in (:(!), :(~), :(+), :(-), :(zero), :(one), :(oneunit),
  @eval ($f)(::Missing) = missing
 end
 for f in (:(Base.zero), :(Base.one), :(Base.oneunit))
+ @eval ($f)(::Type{Missing}) = missing
  @eval function $(f)(::Type{Union{T, Missing}}) where T
  T === Any && throw(MethodError($f, (Any,))) # To prevent StackOverflowError
  $f(T)

diff --git a/test/missing.jl b/test/missing.jl
@@ -179,6 +179,10 @@ Base.one(::Type{Unit}) = 1
  @test oneunit(Union{T, Missing}) === T(1)
  end
 
+ @test zero(Missing) === missing
+ @test one(Missing) === missing
+ @test oneunit(Missing) === missing
+
  @test_throws MethodError zero(Any)
  @test_throws MethodError one(Any)
  @test_throws MethodError oneunit(Any)