Use G isa Array check and copyto! in fgh!

Author: wsmoses

lib/OptimizationBase/ext/OptimizationEnzymeExt.jl

@@ -195,8 +195,13 @@ function OptimizationBase.instantiate_function(
             vdθ = Tuple((Array(r) for r in eachrow(I(length(θ)) * one(eltype(θ)))))
             vdbθ = Tuple(zeros(eltype(θ), length(θ)) for i in eachindex(θ))
             θ_arr = θ isa Array ? θ : Array(θ)
-            G_arr = G isa Array ? G : Array(G)
-            Enzyme.make_zero!(G_arr)
+            if G isa Array
+                G_arr = G
+                Enzyme.make_zero!(G)
+            else
+                G_arr = Array(G)
+                Enzyme.make_zero!(G_arr)
+            end
 
             Enzyme.autodiff(
                 fmode,
@@ -208,8 +213,8 @@ function OptimizationBase.instantiate_function(
                 Const(p)
             )
 
-            if G !== G_arr
-                G .= G_arr
+            if !(G isa Array)
+                copyto!(G, G_arr)
             end
 
             for i in eachindex(θ)