From 50ae2d8e01369cbef4595f260528cfb1ab8de5a6 Mon Sep 17 00:00:00 2001
From: Alex Arslan <ararslan@comcast.net>
Date: Wed, 13 Feb 2019 17:09:52 -0800
Subject: [PATCH] Handle missing values in clamp

---
 NEWS.md         | 1 +
 base/math.jl    | 1 +
 test/missing.jl | 2 ++
 3 files changed, 4 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index ca6ed48b754c9..3be42c2b417b2 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -33,6 +33,7 @@ Standard library changes
   (environment, flags, working directory, etc) if `x` is the first interpolant and errors
   otherwise ([#24353]).
 * `IPAddr` subtypes now behave like scalars when used in broadcasting ([#32133]).
+* `clamp` can now handle missing values ([#31066]).
 
 #### Libdl
 
diff --git a/base/math.jl b/base/math.jl
index f990f8b6282df..79d9599da5045 100644
--- a/base/math.jl
+++ b/base/math.jl
@@ -1083,5 +1083,6 @@ for f in (:(acos), :(acosh), :(asin), :(asinh), :(atan), :(atanh),
           :(log2), :(exponent), :(sqrt))
     @eval $(f)(::Missing) = missing
 end
+clamp(::Missing, lo, hi) = missing
 
 end # module
diff --git a/test/missing.jl b/test/missing.jl
index 8815daa093641..db64b3176b0cb 100644
--- a/test/missing.jl
+++ b/test/missing.jl
@@ -164,6 +164,8 @@ Base.one(::Type{Unit}) = 1
         @test ismissing(f(missing))
     end
 
+    @test ismissing(clamp(missing, 1, 2))
+
     for T in (Int, Float64)
         @test zero(Union{T, Missing}) === T(0)
         @test one(Union{T, Missing}) === T(1)