From ff251a017c5279cc8d7c139c0757238561c9a7aa Mon Sep 17 00:00:00 2001
From: Kristoffer <kcarlsson89@gmail.com>
Date: Sun, 3 Oct 2021 12:12:25 +0200
Subject: [PATCH] define ArithmeticStyle for Dual

---
 src/dual.jl          | 5 +++++
 test/GradientTest.jl | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/src/dual.jl b/src/dual.jl
index 580b5197..9c9b0d82 100644
--- a/src/dual.jl
+++ b/src/dual.jl
@@ -20,6 +20,11 @@ struct Dual{T,V,N} <: Real
     end
 end
 
+##########
+# Traits #
+##########
+Base.ArithmeticStyle(::Type{<:Dual{T,V}}) where {T,V} = Base.ArithmeticStyle(V)
+
 ##############
 # Exceptions #
 ##############
diff --git a/test/GradientTest.jl b/test/GradientTest.jl
index ac949944..707fcd68 100644
--- a/test/GradientTest.jl
+++ b/test/GradientTest.jl
@@ -162,4 +162,11 @@ end
     @test_throws DimensionMismatch ForwardDiff.gradient(identity, fill(2pi, 10^6)) # chunk_mode_gradient
 end
 
+@testset "ArithmeticStyle" begin
+    function f(p)
+        sum(collect(0.0:p[1]:p[2]))
+    end
+    @test ForwardDiff.gradient(f, [0.2,25.0]) == [7875.0, 0.0]
+end
+
 end # module