diff --git a/base/iterators.jl b/base/iterators.jl
index 5cd53cb6ebc2b..4eddbb471526a 100644
--- a/base/iterators.jl
+++ b/base/iterators.jl
@@ -1216,7 +1216,6 @@ function eltype(::Type{Flatten{I}}) where {I<:Union{Tuple,NamedTuple}}
     T
 end
 
-promote_typejoin(map(eltype, fieldtypes(I))...)
 eltype(::Type{Flatten{Tuple{}}}) = eltype(Tuple{})
 IteratorEltype(::Type{Flatten{I}}) where {I} = _flatteneltype(I, IteratorEltype(I))
 IteratorEltype(::Type{Flatten{Tuple{}}}) = IteratorEltype(Tuple{})