Hook up Eras to forward code gen

Author: oxinabox

src/stage1/forward.jl

@@ -169,6 +169,7 @@ end
 #E eras mode, this controls if we should Error if it isn't Taylor. This should be a Bool
 struct ∂☆internal{N, E}; end
 struct ∂☆recurse{N, E}; end
+∂☆recurse{N}() where N = ∂☆recurse{N,false}
 struct ∂☆shuffle{N}; end
 
 function shuffle_base(r)

src/stage1/recurse_fwd.jl

@@ -72,9 +72,9 @@ function ∂☆builtin((f_bundle, args...))
     throw(DomainError(f, "No `ChainRulesCore.frule` found for the built-in function `$sig`"))
 end
 
-function fwd_transform(ci::CodeInfo, args...)
+function fwd_transform(ci, mi, nargs, N, E)
     newci = copy(ci)
-    fwd_transform!(newci, args...)
+    fwd_transform!(newci, mi, nargs, N, E)
     return newci
 end
 
@@ -214,7 +214,7 @@ function fwd_transform!(ci::CodeInfo, mi::MethodInstance, nargs::Int, N::Int, E)
 end
 
 function perform_fwd_transform(world::UInt, source::LineNumberNode,
-                               @nospecialize(ff::Type{∂☆recurse{N}}), @nospecialize(args)) where {N}
+                               @nospecialize(ff::Type{∂☆recurse{N,E}}), @nospecialize(args)) where {N,E}
     if all(x->x <: ZeroBundle, args)
         return generate_lambda_ex(world, source,
             Core.svec(:ff, :args), Core.svec(), :(∂☆passthrough(args)))
@@ -237,7 +237,7 @@ function perform_fwd_transform(world::UInt, source::LineNumberNode,
     mi = Core.Compiler.specialize_method(match)
     ci = Core.Compiler.retrieve_code_info(mi, world)
 
-    return fwd_transform(ci, mi, length(args)-1, N)
+    return fwd_transform(ci, mi, length(args)-1, N, E)
 end
 
 @eval function (ff::∂☆recurse)(args...)

src/stage1/termination.jl

@@ -44,7 +44,10 @@ which(Tuple{∂⃖{N}, ∂⃖{1}, Vararg{Any}} where {N}).recursion_relation = f
            isa(Base.unwrap_unionall(new_sig.parameters[1].parameters[1]), Int)
 end
 
-for (;method) in Base._methods_by_ftype(Tuple{Diffractor.∂☆recurse{N}, Vararg{Any}} where {N}, nothing, -1, get_world_counter())
+for (;method) in [
+        Base._methods_by_ftype(Tuple{Diffractor.∂☆recurse{N}, Vararg{Any}} where {N}, nothing, -1, get_world_counter());
+        Base._methods_by_ftype(Tuple{Diffractor.∂☆recurse{N, E}, Vararg{Any}} where {N, E}, nothing, -1, get_world_counter());
+]
     method.recursion_relation = function (method1, method2, parent_sig, new_sig)
         # Recursion from a higher to a lower order is always allowed
         parent_order = parent_sig.parameters[1].parameters[1]