Fix promotion with nonconcrete types (#71)

* Fix promotion with nonconcrete types

* Add Combinatorics for tests

Author: blegat

Project.toml

@@ -20,11 +20,12 @@ julia = "1"
 
 [extras]
 BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
+Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 NBInclude = "0db19996-df87-5ea3-a455-e3a50d440464"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Pkg", "NBInclude", "LinearAlgebra", "Test", "Random", "BenchmarkTools"]
+test = ["Pkg", "NBInclude", "LinearAlgebra", "Test", "Random", "BenchmarkTools", "Combinatorics"]

src/promotion.jl

@@ -50,3 +50,18 @@ end
     vars = merge(V1, V2...)
     Monomial{vars, length(vars)}
 end
+
+MP.promote_rule(::Type{Term{C,M1} where {C}}, M2::Type{<:MonomialLike}) where {M1} = (Term{C,promote_type(M1, M2)} where {C})
+MP.promote_rule(M1::Type{<:MonomialLike}, ::Type{Term{C,M2} where {C}}) where {M2} = (Term{C,promote_type(M1, M2)} where {C})
+MP.promote_rule(::Type{Term{C,M1} where {C}}, ::Type{Term{T,M2}}) where {T,M1,M2} = (Term{C,promote_type(M1, M2)} where {C})
+MP.promote_rule(::Type{Term{T,M2}}, ::Type{Term{C,M1} where {C}}) where {T,M1,M2} = (Term{C,promote_type(M1, M2)} where {C})
+MP.promote_rule(::Type{Term{C,M1} where {C}}, ::Type{Term{T,M2}}) where {T,M1,M2} = (Term{C,promote_type(M1, M2)} where {C})
+MP.promote_rule(::Type{<:Polynomial}, ::Type{Term{C,M} where {C}}) where {M} = Polynomial
+MP.promote_rule(::Type{Term{C,M} where {C}}, ::Type{<:Polynomial}) where {M} = Polynomial
+MP.promote_rule(::Type{Polynomial}, ::Type{<:PolynomialLike}) = Polynomial
+MP.promote_rule(::Type{<:PolynomialLike}, ::Type{Polynomial}) = Polynomial
+MP.promote_rule_constant(::Type, ::Type{Polynomial}) = Any
+MP.promote_rule_constant(::Type, ::Type{Term{C,M} where {C}}) where {M} = Any
+
+Base.convert(::Type{Term{C,M} where {C}}, m::MonomialLike) where {M} = MP.term(convert(M, m))
+Base.convert(::Type{Polynomial}, t::TermLike) = MP.polynomial(t)