Infinite recursion in wrapped arrays

Project.toml

@@ -1,6 +1,6 @@
 name = "FiniteDifferences"
 uuid = "26cc04aa-876d-5657-8c51-4c34ba976000"
-version = "0.12.1"
+version = "0.12.2"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

src/to_vec.jl

@@ -54,7 +54,7 @@ function to_vec(x::AbstractVector)
 end
 
 function to_vec(x::AbstractArray)
-    x_vec, from_vec = to_vec(vec(x))
+    x_vec, from_vec = to_vec(collect(vec(x)))
 
     function Array_from_vec(x_vec)
         return oftype(x, reshape(from_vec(x_vec), size(x)))

test/to_vec.jl

@@ -18,6 +18,9 @@ struct FillVector <: AbstractVector{Float64}
     len::Int
 end
 
+Base.size(x::FillVector) = (x.len,)
+Base.getindex(x::FillVector, n::Int) = x.x
+
 # For testing Composite{ThreeFields}
 struct ThreeFields
     a
@@ -32,8 +35,14 @@ struct Nested
     y::Singleton
 end
 
-Base.size(x::FillVector) = (x.len,)
-Base.getindex(x::FillVector, n::Int) = x.x
+# for testing wrapped arrays
+struct WrappedArray{T, V<:AbstractMatrix{T}} <: AbstractMatrix{T}
+    a::V
+end
+
+Base.size(w::WrappedArray) = size(w.a)
+Base.getindex(w::WrappedArray, i, j) = getindex(w.a, i, j)
+Base.convert(::Type{WrappedArray{T, Array{T, N}}}, a::Array{T, N}) where {T, N} = WrappedArray(a)
 
 function test_to_vec(x::T; check_inferred = true) where {T}
     check_inferred && @inferred to_vec(x)
@@ -179,4 +188,9 @@ end
         nested = Nested(ThreeFields(1.0, 2.0, "Three"), Singleton())
         test_to_vec(nested; check_inferred=false) # map
     end
+
+    @testset "WrappedArray" begin
+        wa = WrappedArray(rand(2, 3))
+        test_to_vec(wa)
+    end
 end