From ad6f42367beed965197c237a6fc832ca809cbdaa Mon Sep 17 00:00:00 2001
From: Luis Benet <lbenet@users.noreply.github.com>
Date: Fri, 12 Jul 2019 11:09:28 -0500
Subject: [PATCH] ArgumentErrorfor promotion  among non-compatible Taylor1 and
 TaylorN (#220)

Fixes #219
---
 src/arithmetic.jl | 4 ++++
 src/conversion.jl | 3 +++
 test/mixtures.jl  | 5 +++++
 3 files changed, 12 insertions(+)

diff --git a/src/arithmetic.jl b/src/arithmetic.jl
index 0b5112ef..1f8bd90c 100644
--- a/src/arithmetic.jl
+++ b/src/arithmetic.jl
@@ -200,6 +200,10 @@ for (f, fc) in ((:+, :(add!)), (:-, :(subst!)))
     end
 end
 
++(a::Taylor1{T}, b::TaylorN{S}) where {T<:NumberNotSeries,S<:NumberNotSeries} =
+    +(promote(a,b)...)
+-(a::Taylor1{T}, b::TaylorN{S}) where {T<:NumberNotSeries,S<:NumberNotSeries} =
+    -(promote(a,b)...)
 
 
 ## Multiplication ##
diff --git a/src/conversion.jl b/src/conversion.jl
index aeba6d31..0c8b0dfb 100644
--- a/src/conversion.jl
+++ b/src/conversion.jl
@@ -200,3 +200,6 @@ promote_rule(::Type{S}, ::Type{T}) where {S<:NumberNotSeries, T<:AbstractSeries}
 
 promote_rule(::Type{S}, ::Type{T}) where
     {S<:AbstractIrrational, T<:AbstractSeries} = promote_rule(T,S)
+
+promote_rule(::Type{Taylor1{T}}, ::Type{TaylorN{S}}) where {T<:NumberNotSeries, S<:NumberNotSeries} =
+    throw(ArgumentError("There is no reasonable promotion among `Taylor1{$T}` and `TaylorN{$S}` types"))
diff --git a/test/mixtures.jl b/test/mixtures.jl
index 4ec22a15..36b93857 100644
--- a/test/mixtures.jl
+++ b/test/mixtures.jl
@@ -273,4 +273,9 @@ using LinearAlgebra, SparseArrays
     Qv = convert.(Taylor1{TaylorN{Float64}}, Pv)
 
     @test TaylorSeries.jacobian(Pv) == TaylorSeries.jacobian(Qv)
+
+    @test_throws ArgumentError Taylor1(2) + TaylorN(1)
+    @test_throws ArgumentError Taylor1(2) - TaylorN(1)
+    @test_throws ArgumentError Taylor1(2) * TaylorN(1)
+    @test_throws ArgumentError TaylorN(2) / Taylor1(1)
 end