From d057de100b672866c71a788fcc6b29267d135eab Mon Sep 17 00:00:00 2001
From: lassepe <lasse.peters@mailbox.org>
Date: Mon, 17 Nov 2025 17:56:34 +0100
Subject: [PATCH 1/6] Test for forward mode jacobians

---
 test/autodiff.jl | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/test/autodiff.jl b/test/autodiff.jl
index 10daa32ee8..a2ea8d3fbf 100644
--- a/test/autodiff.jl
+++ b/test/autodiff.jl
@@ -102,6 +102,19 @@ end
     @test res[1] ≈ ones(2, 2)
 end
 
+f_sincos(x) = map(sin, x) + map(cos, reverse(x))
+f_sincos_jac(x) = [cos(x[i]) * (i == j ? 1 : 0) - sin(x[end-i+1]) * (i == (length(x) - j + 1) ? 1 : 0) for i in 1:length(x), j in 1:length(x)]
+
+@testset "Forward Jacobian" begin
+    jac(x) = only(Enzyme.jacobian(Enzyme.Forward, f_sincos, x))
+    x_r = Reactant.to_rarray(rand(10))
+
+    j_gt = f_sincos_jac(x_r)
+    j_reactant = Reactant.@jit jac(x_r)
+
+    @test j_reactant ≈ j_gt
+end
+
 mutable struct StateReturn
     st::Any
 end

From ad662d378b476930fba08ef68e4fff8a8f6dded2 Mon Sep 17 00:00:00 2001
From: lassepe <lasse.peters@mailbox.org>
Date: Fri, 21 Nov 2025 23:32:40 +0100
Subject: [PATCH 2/6] Add at-allowscalar

---
 test/autodiff.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/autodiff.jl b/test/autodiff.jl
index a2ea8d3fbf..5fd0188c0d 100644
--- a/test/autodiff.jl
+++ b/test/autodiff.jl
@@ -109,7 +109,7 @@ f_sincos_jac(x) = [cos(x[i]) * (i == j ? 1 : 0) - sin(x[end-i+1]) * (i == (lengt
     jac(x) = only(Enzyme.jacobian(Enzyme.Forward, f_sincos, x))
     x_r = Reactant.to_rarray(rand(10))
 
-    j_gt = f_sincos_jac(x_r)
+    j_gt = Reactant.@allowscalar f_sincos_jac(x_r)
     j_reactant = Reactant.@jit jac(x_r)
 
     @test j_reactant ≈ j_gt

From b6d85091dfdb71c0995ae0e3ecec57905d4352c8 Mon Sep 17 00:00:00 2001
From: lassepe <lasse.peters@mailbox.org>
Date: Fri, 21 Nov 2025 23:36:39 +0100
Subject: [PATCH 3/6] Add Enzyme.tupsack dispatch for Reactant.RArray

---
 src/Enzyme.jl | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/Enzyme.jl b/src/Enzyme.jl
index e263e4d716..b7d24dc141 100644
--- a/src/Enzyme.jl
+++ b/src/Enzyme.jl
@@ -69,6 +69,20 @@ end
     return Base.zero(x)
 end
 
+@inline function Enzyme.tupstack(
+    data::Tuple{Vararg{<:Reactant.RArray{T}}},
+    outshape::Tuple{Vararg{Int}},
+    inshape::Tuple{Vararg{Int}},
+) where {T}
+    res = similar(first(data), outshape..., inshape...)
+    c = CartesianIndices(outshape)
+    tail_dims = map(Returns(:), inshape)
+    for (i, val) in enumerate(data)
+        @inbounds res[c[i], tail_dims...] = val
+    end
+    return res
+end
+
 macro register_make_zero_inplace(sym)
     quote
         @inline function $sym(prev::RArray{T,N})::Nothing where {T<:AbstractFloat,N}

From 2e06801ef30ecac79f5e12daaf0d5b268dc0a9b7 Mon Sep 17 00:00:00 2001
From: William Moses <gh@wsmoses.com>
Date: Sat, 22 Nov 2025 11:15:33 -0600
Subject: [PATCH 4/6] Update Enzyme.jl

---
 src/Enzyme.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Enzyme.jl b/src/Enzyme.jl
index b7d24dc141..1da1c7dbc9 100644
--- a/src/Enzyme.jl
+++ b/src/Enzyme.jl
@@ -70,7 +70,7 @@ end
 end
 
 @inline function Enzyme.tupstack(
-    data::Tuple{Vararg{<:Reactant.RArray{T}}},
+    data::Tuple{Vararg{<:RArray{T}}},
     outshape::Tuple{Vararg{Int}},
     inshape::Tuple{Vararg{Int}},
 ) where {T}

From 5204feaa77c19e58d24402ab5d3cc48ea9f1af25 Mon Sep 17 00:00:00 2001
From: William Moses <gh@wsmoses.com>
Date: Sat, 22 Nov 2025 13:57:43 -0600
Subject: [PATCH 5/6] Update Enzyme.jl

---
 src/Enzyme.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Enzyme.jl b/src/Enzyme.jl
index 1da1c7dbc9..43553add5b 100644
--- a/src/Enzyme.jl
+++ b/src/Enzyme.jl
@@ -70,10 +70,10 @@ end
 end
 
 @inline function Enzyme.tupstack(
-    data::Tuple{Vararg{<:RArray{T}}},
+    data::Tuple{Vararg{<:RArray}},
     outshape::Tuple{Vararg{Int}},
     inshape::Tuple{Vararg{Int}},
-) where {T}
+)
     res = similar(first(data), outshape..., inshape...)
     c = CartesianIndices(outshape)
     tail_dims = map(Returns(:), inshape)

From 97c29f3c1baae080531c5a78526775977106e8a2 Mon Sep 17 00:00:00 2001
From: William Moses <gh@wsmoses.com>
Date: Sat, 22 Nov 2025 17:48:02 -0600
Subject: [PATCH 6/6] Update Enzyme.jl

---
 src/Enzyme.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Enzyme.jl b/src/Enzyme.jl
index 43553add5b..6be770720f 100644
--- a/src/Enzyme.jl
+++ b/src/Enzyme.jl
@@ -70,7 +70,7 @@ end
 end
 
 @inline function Enzyme.tupstack(
-    data::Tuple{Vararg{<:RArray}},
+    data::Tuple{<:RArray, Vararg{<:RArray}},
     outshape::Tuple{Vararg{Int}},
     inshape::Tuple{Vararg{Int}},
 )