abstract B type A<:B end
type C<:B
end
promote_rule(::Type{A},::Type{C}) = C
@assert promote_type(A,C) == B
Whether I define the promotion_rule or not, the promote_type is always B.
abstract B type A<:B end
type C<:B
end
promote_rule(::Type{A},::Type{C}) = C
@assert promote_type(A,C) == B
Whether I define the promotion_rule or not, the promote_type is always B.