diff --git a/src/units/abilities.cpp b/src/units/abilities.cpp
index 38152e40612..f5d865c51ed 100644
--- a/src/units/abilities.cpp
+++ b/src/units/abilities.cpp
@@ -1297,48 +1297,41 @@ static bool overwrite_special_affects(const config& special)
 	return (apply_to == "one_side" || apply_to == "both_sides");
 }
 
-unit_ability_list attack_type::overwrite_special_checking(const std::string& ability, const unit_ability_list& temp_list, const unit_ability_list& abil_list, const std::string& filter_self, bool is_special) const
+unit_ability_list attack_type::overwrite_special_checking(const std::string& ability, unit_ability_list input, unit_ability_list overwriters, const std::string& filter_self, bool is_special) const
 {
-	bool overwrite_self = false;
-	bool overwrite_opponent = false;
-	bool overwrite_either = false;
-
-	for(const auto& i : abil_list) {
-		if((*i.ability_cfg)["overwrite_specials"] == "both_sides") {
-			overwrite_either = true;
-			break;
-		}
-		if((*i.ability_cfg)["overwrite_specials"] == "one_side" && special_active_impl(shared_from_this(), other_attack_, *i.ability_cfg, AFFECT_SELF, ability, filter_self) && !overwrite_self) {
-			overwrite_self = true;
-		}
-		if((*i.ability_cfg)["overwrite_specials"] == "one_side" && special_active_impl(other_attack_, shared_from_this(), *i.ability_cfg, AFFECT_OTHER, ability, filter_self) && !overwrite_opponent) {
-			overwrite_opponent = true;
+	for(unit_ability_list::iterator i = overwriters.begin(); i != overwriters.end();) {
+		if(!overwrite_special_affects(*i->ability_cfg)) {
+			i = overwriters.erase(i);
+		} else {
+			++i;
 		}
 	}
-	if(!overwrite_either && !overwrite_self && !overwrite_opponent){
-		return temp_list;
+	if(overwriters.empty()){
+		return input;
 	}
 
-	if(!overwrite_either && overwrite_self && overwrite_opponent){
-		overwrite_either = true;
-	}
-
-	// At this point we need to return a changed list, so create a non-const one to return
-	unit_ability_list overwrite_list;
-	for(const auto& i : temp_list) {
-		bool overwrite = false;
-		if(overwrite_either){
-			overwrite = !is_special && overwrite_special_affects(*i.ability_cfg);
-		} else if(overwrite_self){
-			overwrite = (!is_special && overwrite_special_affects(*i.ability_cfg)) || special_active_impl(other_attack_, shared_from_this(), *i.ability_cfg, AFFECT_OTHER, ability, filter_self);
-		} else if(overwrite_opponent){
-			overwrite = (!is_special && overwrite_special_affects(*i.ability_cfg)) || special_active_impl(shared_from_this(), other_attack_, *i.ability_cfg, AFFECT_SELF, ability, filter_self);
-		}
-		if(overwrite) {
-			overwrite_list.emplace_back(i);
+	for(const auto& i : overwriters) {
+		bool affect_side = ((*i.ability_cfg)["overwrite_specials"] == "one_side");
+		for(unit_ability_list::iterator j = input.begin(); j != input.end();) {
+			bool is_overwritable = (is_special || !overwrite_special_affects(*j->ability_cfg));
+			bool one_side_overwritable = true;
+			if(affect_side && is_overwritable){
+				if(special_active_impl(shared_from_this(), other_attack_, *i.ability_cfg, AFFECT_SELF, ability, filter_self)){
+					one_side_overwritable = special_active_impl(shared_from_this(), other_attack_, *j->ability_cfg, AFFECT_SELF, ability, filter_self);
+				}
+				else if(special_active_impl(other_attack_, shared_from_this(), *i.ability_cfg, AFFECT_OTHER, ability, filter_self)){
+					one_side_overwritable = special_active_impl(other_attack_, shared_from_this(), *j->ability_cfg, AFFECT_OTHER, ability, filter_self);
+				}
+			}
+			is_overwritable = is_overwritable && one_side_overwritable;
+			if(is_overwritable) {
+				j = input.erase(j);
+			} else {
+				++j;
+			}
 		}
 	}
-	return overwrite_list;
+	return input;
 }
 
 	/**
diff --git a/src/units/attack_type.hpp b/src/units/attack_type.hpp
index fb1221ad124..4a281015637 100644
--- a/src/units/attack_type.hpp
+++ b/src/units/attack_type.hpp
@@ -127,14 +127,17 @@ private:
 
 	// Configured as a bit field, in case that is useful.
 	enum AFFECTS { AFFECT_SELF=1, AFFECT_OTHER=2, AFFECT_EITHER=3 };
-	/** overwrite_special_checking : return an unit_ability_list list after checking presence or not of overwrite_specials
+	/**
+	 * Filter a list of abilities or weapon specials, removing any entries that are overridden by
+	 * the overwrite_specials attributes of a second list.
+	 *
 	 * @param ability The special ability type who is being checked.
-	 * @param temp_list the list checked and returned.
-	 * @param abil_list list checked for verify presence of overwrite_specials .
-	 * @param filter_self name of [filter_"self/student"] if is abilities or specials who are checked
-	 * @param is_special for determine if list is a special or a ability.
+	 * @param input list to check, a filtered copy of this list is returned by the function.
+	 * @param overwriters list that may have overwrite_specials attributes.
+	 * @param filter_self name of [filter_"self/student"] if is abilities or specials who are checked.
+	 * @param is_special if true, input contains weapon specials; if false, it contains abilities.
 	 */
-	unit_ability_list overwrite_special_checking(const std::string& ability, const unit_ability_list& temp_list, const unit_ability_list& abil_list, const std::string& filter_self, bool is_special) const;
+	unit_ability_list overwrite_special_checking(const std::string& ability, unit_ability_list input, unit_ability_list overwriters, const std::string& filter_self, bool is_special) const;
 	/** check_self_abilities : return an boolean value for checking of activities of abilities used like weapon
 	 * @return True if the special @a special is active.
 	 * @param cfg the config to one special ability checked.