fixes in polyform

src/polyform.jl

@@ -118,10 +118,11 @@ function polyize(x, pvar2sym, sym2term, vtype, pow, Fs, recurse)
             # create a new symbol to store this
 
             y = if recurse
-                similarterm(x,
-                            op,
-                            map(a->PolyForm(a, pvar2sym, sym2term, vtype; Fs, recurse),
-                                args), symtype(x))
+                maketerm(typeof(x),
+                         op,
+                         map(a->PolyForm(a, pvar2sym, sym2term, vtype; Fs, recurse), args),
+                         symtype(x),
+                         metadata(x))
             else
                 x
             end
@@ -175,7 +176,7 @@ isexpr(x::PolyForm) = true
 iscall(x::Type{<:PolyForm}) = true
 iscall(x::PolyForm) = true
 
-function similarterm(::Type{<:PolyForm}, f, args, symtype, metadata)
+function maketerm(::Type{<:PolyForm}, f, args, symtype, metadata)
     basicsymbolic(t, f, args, symtype, metadata)
 end
 function maketerm(::Type{<:PolyForm}, f::Union{typeof(*), typeof(+), typeof(^)},
@@ -248,8 +249,10 @@ multivariate polynomials implementation.
 expand(expr) = unpolyize(PolyForm(expr, Fs=Union{typeof(+), typeof(*), typeof(^)}, recurse=true))
 
 function unpolyize(x)
-    simterm(x, f, args; kw...) = similarterm(x, f, args, symtype(x); kw...)
-    Postwalk(identity, similarterm=simterm)(x)
+    # we need a special makterm here because the default one used in Postwalk will call
+    # promote_symtype to get the new type, but we just want to forward that in case
+    # promote_symtype is not defined for some of the expressions here.
+    Postwalk(identity, maketerm=(T,f,args,sT,m) -> maketerm(T, f, args, symtype(x), m))(x)
 end
 
 function toterm(x::PolyForm)
@@ -301,7 +304,7 @@ function add_divs(x, y)
     end
 end
 
-function frac_similarterm(x, f, args; kw...)
+function frac_maketerm(T, f, args, stype, metadata)
     if f in (*, /, \, +, -)
         f(args...)
     elseif f == (^)
@@ -311,7 +314,7 @@ function frac_similarterm(x, f, args; kw...)
             args[1]^args[2]
         end
     else
-        similarterm(x, f, args; kw...)
+        maketerm(T, f, args, stype, metadata)
     end
 end
 
@@ -333,8 +336,8 @@ function simplify_fractions(x; polyform=false)
     sdiv(a) = isdiv(a) ? simplify_div(a) : a
 
     expr = Postwalk(sdiv ∘ quick_cancel,
-                    similarterm=frac_similarterm)(Postwalk(add_with_div,
-                                                           similarterm=frac_similarterm)(x))
+                    maketerm=frac_maketerm)(Postwalk(add_with_div,
+                                                           maketerm=frac_maketerm)(x))
 
     polyform ? expr : unpolyize(expr)
 end