deprecate convert

Author: Miha Zgubic

src/deprecated.jl

@@ -56,4 +56,19 @@ for T in (:Thunk, :InplaceableThunk)
 end
 
 
-Base.@deprecate InplaceableThunk(t::Thunk, add!) InplaceableThunk(add!, t)
+Base.@deprecate InplaceableThunk(t::Thunk, add!) InplaceableThunk(add!, t)
+
+const CONVERT_DEPRECATION = "convert(::Type{T}, t::Tangent) is deprecated, use ChainRulesCore.backing(t) instead"
+
+function Base.convert(::Type{<:NamedTuple}, comp::Tangent{<:Any, <:NamedTuple})
+    Base.depwarn(CONVERT_DEPRECATION, :convert)
+    return backing(comp)
+end
+function Base.convert(::Type{<:Tuple}, comp::Tangent{<:Any, <:Tuple})
+    Base.depwarn(CONVERT_DEPRECATION, :convert)
+    return backing(comp)
+end
+function Base.convert(::Type{<:Dict}, comp::Tangent{<:Dict, <:Dict})
+    Base.depwarn(CONVERT_DEPRECATION, :convert)
+    return backing(comp)
+end

src/differentials/composite.jl

@@ -68,10 +68,6 @@ function Base.show(io::IO, comp::Tangent{P}) where P
     end
 end
 
-Base.convert(::Type{<:NamedTuple}, comp::Tangent{<:Any, <:NamedTuple}) = backing(comp)
-Base.convert(::Type{<:Tuple}, comp::Tangent{<:Any, <:Tuple}) = backing(comp)
-Base.convert(::Type{<:Dict}, comp::Tangent{<:Dict, <:Dict}) = backing(comp)
-
 Base.getindex(comp::Tangent, idx) = getindex(backing(comp), idx)
 
 # for Tuple