fix: special handling for concatenation of numbers

Author: avik-pal

src/TracedRNumber.jl

@@ -209,3 +209,13 @@ struct TypeCast{T<:ReactantPrimitives} <: Function end
 (::TypeCast{T})(x::TracedRNumber{T2}) where {T,T2} = promote_to(TracedRNumber{T}, x)
 
 Base.float(x::TracedRNumber{T}) where {T} = promote_to(TracedRNumber{float(T)}, x)
+
+# Concatenation. Numbers in Julia are handled in a much less generic fashion than arrays
+Base.vcat(x::TracedRNumber...) = vcat(map(Base.Fix2(broadcast_to_size, (1,)), x)...)
+function Base.typed_vcat(::Type{T}, x::TracedRNumber...) where {T}
+    return Base.typed_vcat(T, map(Base.Fix2(broadcast_to_size, (1,)), x)...)
+end
+Base.hcat(x::TracedRNumber...) = hcat(map(Base.Fix2(broadcast_to_size, (1, 1)), x)...)
+function Base.typed_hcat(::Type{T}, x::TracedRNumber...) where {T}
+    return Base.typed_hcat(T, map(Base.Fix2(broadcast_to_size, (1, 1)), x)...)
+end