Resolve #235 (#237)

* Fix mul

* Bump patch

Author: willtebbutt

Project.toml

@@ -1,6 +1,6 @@
 name = "ReverseDiff"
 uuid = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
-version = "1.15.0"
+version = "1.15.1"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

src/derivatives/linalg/arithmetic.jl

@@ -301,7 +301,7 @@ for (f, F) in ((:transpose, :Transpose), (:adjoint, :Adjoint))
            # f(a) * b
         function reverse_mul!(output, output_deriv, a::$F, b, a_tmp, b_tmp)
             _a = ($f)(a)
-            istracked(_a) && increment_deriv!(_a, ($f)(mul!(a_tmp, output_deriv, value(b))))
+            istracked(_a) && increment_deriv!(_a, ($f)(mul!(a_tmp, output_deriv, ($f)(value(b)))))
             istracked(b) && increment_deriv!(b, mul!(b_tmp, ($f)(mulargvalue(a)), ($f)(output_deriv)))
         end
         # f(a) * f(b)

test/derivatives/LinAlgTests.jl

@@ -277,4 +277,8 @@ test_println("*(A, B) functions", "*(transpose(a), adjoint(b))")
 test_arr2arr(*, transpose(a), adjoint(b), tp)
 test_arr2arr_inplace(mul!, *, x, transpose(a), adjoint(b), tp)
 
+# Prevent regression on https://github.com/JuliaDiff/ReverseDiff.jl/issues/235
+A = [1 2; 3 4]; x = [5, 6];
+@test ReverseDiff.gradient(y -> sum(y'*A), x) == [3, 7]
+
 end # module