diff --git a/src/layers/basic.jl b/src/layers/basic.jl
index 905844d7..4754467d 100644
--- a/src/layers/basic.jl
+++ b/src/layers/basic.jl
@@ -30,7 +30,7 @@ end
 @forward Chain.layers Base.getindex, Base.length, Base.first, Base.last,
   Base.iterate, Base.lastindex
 
-functor(c::Chain) = c.layers, ls -> Chain(ls...)
+functor(::Type{<:Chain}, c) = c.layers, ls -> Chain(ls...)
 
 applychain(::Tuple{}, x) = x
 applychain(fs::Tuple, x) = applychain(tail(fs), first(fs)(x))