diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index 6efc9d5f22632..fcea42e369317 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -1732,7 +1732,7 @@ cat_similar(A, ::Type{T}, shape::Vector) where T = Array{T}(undef, shape...)
 cat_similar(A::Array, ::Type{T}, shape::Tuple) where T = Array{T}(undef, shape)
 cat_similar(A::Array, ::Type{T}, shape::Vector, ::Val{N}) where {T, N} = Array{T, N}(undef, shape...)
 cat_similar(A::AbstractArray, T::Type, shape::Tuple) = similar(A, T, shape)
-cat_similar(A::AbstractArray, T::Type, shape::Vector, ::Val{N}) = similar(A, T, shape...)
+cat_similar(A::AbstractArray, T::Type, shape::Vector, ::Val{N}) where N = similar(A, T, shape...)
 
 # These are for backwards compatibility (even though internal)
 cat_shape(dims, shape::Tuple{Vararg{Int}}) = shape