Handle missing values in clamp

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
 

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

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)