Fast path for inferred cases

Author: p-zubieta

base/broadcast.jl

@@ -241,6 +241,9 @@ end
 
 # broadcast methods that dispatch on the type found by inference
 function _broadcast_t(f, ::Type{Any}, shape, iter, As...)
+    if isempty(iter)
+        return similar(Array{Any}, shape)
+    end
     nargs = length(As)
     keeps, Idefaults = map_newindexer(shape, As)
     st = start(iter)
@@ -272,14 +275,16 @@ ziptype(A, B) = Zip2{Tuple{eltype(A)},Tuple{eltype(B)}}
 
 # broadcast methods that dispatch on the type of the final container
 @inline function broadcast_c(f, ::Type{Array}, As...)
-    S = _default_eltype(Generator{ziptype(As...),ftype(f, As...)})
+    T = _default_eltype(Generator{ziptype(As...),ftype(f, As...)})
     shape = broadcast_indices(As...)
     iter = CartesianRange(shape)
+    if isleaftype(T)
+        return _broadcast_t(f, T, shape, iter, As...)
+    end
     if isempty(iter)
-        return similar(Array{S}, shape)
+        return similar(Array{T}, shape)
     end
-    T = isleaftype(S) ? S : Any
-    return _broadcast_t(f, T, shape, iter, As...)
+    return _broadcast_t(f, Any, shape, iter, As...)
 end
 function broadcast_c(f, ::Type{Tuple}, As...)
     shape = broadcast_indices(As...)