diff --git a/crates/prolog_parser/src/parser.rs b/crates/prolog_parser/src/parser.rs
index f3655232..a623f9f4 100644
--- a/crates/prolog_parser/src/parser.rs
+++ b/crates/prolog_parser/src/parser.rs
@@ -469,10 +469,6 @@ impl<'a, R: Read> Parser<'a, R> {
                     return false;
                 }
             }
-
-            if arity >= 2 && is_prefix!(self.stack[idx].spec) && self.stack[idx].priority > 0 {
-                return false;
-            }
         } else {
             return false;
         }
diff --git a/src/lib/builtins.pl b/src/lib/builtins.pl
index c5a9d39a..975a07c1 100644
--- a/src/lib/builtins.pl
+++ b/src/lib/builtins.pl
@@ -1170,7 +1170,7 @@ op(Priority, OpSpec, Op) :-
     ;  valid_op(Op), op_priority(Priority), op_specifier(OpSpec) ->
        '$op'(Priority, OpSpec, Op)
     ;  list_of_op_atoms(Op), op_priority(Priority), op_specifier(OpSpec) ->
-       lists:maplist(op_(Priority, OpSpec), Op),
+       lists:maplist(builtins:op_(Priority, OpSpec), Op),
        !
     ;  throw(error(type_error(list, Op), op/3)) % 8.14.3.3 f)
     ).