Revert "comment out trinary rules"

Project.toml

@@ -1,6 +1,6 @@
 name = "DiffRules"
 uuid = "b552c78f-8df3-52c6-915a-8e097449b14b"
-version = "1.3.1"
+version = "1.4.0"
 
 [deps]
 NaNMath = "77ba4419-2d1f-58cd-9bb1-8ffee604a2e3"

src/rules.jl

@@ -100,14 +100,10 @@ end
 # trinary #
 #---------#
 
-#=
-
 @define_diffrule Base.muladd(x, y, z) = :($y), :($x), :(one($z))
 @define_diffrule Base.fma(x, y, z)    = :($y), :($x), :(one($z))
 
-@define_diffrule Base.ifelse(p, x, y) = false, :($p), :(!$p)
-
-=#
+@define_diffrule Base.ifelse(p, x, y) = NaN, :($p), :(!$p)
 
 ####################
 # SpecialFunctions #

test/runtests.jl

@@ -47,7 +47,6 @@ for (M, f, arity) in DiffRules.diffrules()
             end
         end
     elseif arity == 3
-        #=
         @test DiffRules.hasdiffrule(M, f, 3)
         derivs = DiffRules.diffrule(M, f, :foo, :bar, :goo)
         @eval begin
@@ -63,7 +62,6 @@ for (M, f, arity) in DiffRules.diffrules()
                 @test isapprox(dz, finitediff(z -> $M.$f(foo, bar, z), goo), rtol=0.05)
             end
         end
-        =#
     end
 end
 
@@ -82,16 +80,16 @@ for xtype in [:Float64, :BigFloat, :Int64]
 end
 
 # Test ifelse separately as first argument is boolean
-#=
 @test DiffRules.hasdiffrule(:Base, :ifelse, 3)
 derivs = DiffRules.diffrule(:Base, :ifelse, :foo, :bar, :goo)
-for cond in [true, false]
+for cond in (true, false)
     @eval begin
         foo = $cond
         bar, gee = randn(2)
         dx, dy, dz = $(derivs[1]), $(derivs[2]), $(derivs[3])
         @test isapprox(dy, finitediff(y -> ifelse(foo, y, goo), bar), rtol=0.05)
         @test isapprox(dz, finitediff(z -> ifelse(foo, bar, z), goo), rtol=0.05)
+        @test isnan(dx)
     end
 end
-=#
+