Fix promotion with polynomial coefficient (#266)

* Fix promotion with polynomial coefficient

* Fix

* Fix tests

Author: blegat

src/promote.jl

@@ -241,7 +241,7 @@ function MA.promote_operation(
 ) where {S,T}
     UT = MA.promote_operation(*, monomial_type(TT), monomial_type(ST))
     U = MA.promote_operation(*, S, T)
-    return promote_operation_constant(*, U, UT)
+    return promote_operation_left_constant(*, U, UT)
 end
 function MA.promote_operation(
     ::typeof(*),
@@ -250,34 +250,34 @@ function MA.promote_operation(
 ) where {S,T}
     UP = MA.promote_operation(*, monomial_type(PT), monomial_type(QT))
     U = MA.promote_sum_mul(S, T)
-    return polynomial_type(promote_operation_constant(*, U, UP))
+    return polynomial_type(promote_operation_left_constant(*, U, UP))
 end
 
-function promote_operation_constant(
+function promote_operation_left_constant(
     ::typeof(*),
     ::Type{T},
     ::Type{M},
 ) where {T,M<:AbstractMonomialLike}
     return term_type(M, T)
 end
 
-function promote_operation_constant(
+function promote_operation_right_constant(
     ::typeof(*),
     ::Type{M},
     ::Type{T},
 ) where {T,M<:AbstractMonomialLike}
     return term_type(M, T)
 end
 
-function promote_operation_constant(
+function promote_operation_left_constant(
     ::typeof(*),
     ::Type{T},
     ::Type{P},
 ) where {T,U,P<:_APL{U}}
     return similar_type(P, MA.promote_operation(*, T, U))
 end
 
-function promote_operation_constant(
+function promote_operation_right_constant(
     ::typeof(*),
     ::Type{P},
     ::Type{T},
@@ -290,15 +290,15 @@ function MA.promote_operation(
     ::Type{T},
     ::Type{P},
 ) where {T,P<:_APL}
-    return promote_operation_constant(*, T, P)
+    return promote_operation_left_constant(*, T, P)
 end
 
 function MA.promote_operation(
     ::typeof(*),
     ::Type{P},
     ::Type{T},
 ) where {T,P<:_APL}
-    return promote_operation_constant(*, P, T)
+    return promote_operation_right_constant(*, P, T)
 end
 
 function MA.promote_operation(

test/promote.jl

@@ -149,3 +149,25 @@ end
         _promote_prod(U, P, P)
     end
 end
+
+@testset "promote_operation with polynomial coefficient" begin
+    Mod.@polyvar x
+    Mod.@polyvar y
+    X = typeof(x)
+    MX = monomial_type(X)
+    TX = term_type(X, Int)
+    PX = polynomial_type(X, Int)
+    Y = typeof(y)
+    TXY = term_type(Y, PX)
+    PXY = polynomial_type(Y, PX)
+    TY = term_type(Y, Int)
+    PY = polynomial_type(Y, Int)
+    for T in [X, MX, TX, PX]
+        __promote_prod(TY, TY, TY)
+        __promote_prod(TXY, TY, TXY)
+        __promote_prod(TXY, TXY, TXY)
+        __promote_prod(PY, PY, PY)
+        __promote_prod(PXY, PY, PXY)
+        __promote_prod(PXY, PXY, PXY)
+    end
+end