type promotion

Author: Qfl3x

src/componentarray.jl

@@ -361,5 +361,8 @@ ComponentVector{Float64}(a = 1.2, h = 4.0, b = 2.3)
 ```
 """
 Base.merge(ca::ComponentVector) = ca
-Base.merge(ca1::ComponentVector, ca2::ComponentVector) = ComponentVector(ca1; ca2...)
+function Base.merge(ca1::ComponentVector{T1}, ca2::ComponentVector{T2}) where {T1, T2}
+    promoted_ca1 = ComponentVector{promot_type(T1, T2)}(ca1)
+    ComponentVector(ca1; ca2...)
+end
 Base.merge(ca1::ComponentVector, ca2::ComponentVector, cs::ComponentVector) = merge(merge(ca1,ca2), others...)