Merge pull request #6712 from Goober5000/a_few_fixes

A few fixes

Author: Goober5000

code/parse/parselo.cpp

@@ -2430,7 +2430,7 @@ void read_raw_file_text(const char *filename, int mode, char *raw_text)
 
 				// Compare filename by lowercase string
 				SCP_string key = filename;
-				std::transform(key.begin(), key.end(), key.begin(), ::tolower);
+				SCP_tolower(key);
 
 				// Check for a hash
 				auto it = retail_hashes.find(key);

code/scripting/api/objs/comm_order.cpp

@@ -60,7 +60,7 @@ ADE_FUNC(selectItem, l_Comm_Item, nullptr, "Selects the item and either proceeds
 	if (!ade_get_args(L, "o", l_Comm_Item.Get(&current)))
 		return ADE_RETURN_FALSE;
 
-	if (current < 0 || current > Num_menu_items) {
+	if (current < 0 || current >= Num_menu_items) {
 		LuaError(L, "Lua tried to select squad message that is not valid!");
 		return ADE_RETURN_FALSE;
 	}

code/scripting/api/objs/ship.cpp

@@ -811,7 +811,7 @@ ADE_VIRTVAR(TargetSubsystem, l_Ship, "subsystem", "Target subsystem of ship.", "
 		}
 	}
 
-	return ade_set_args(L, "o", l_Subsystem.Set(ship_subsys_h(&Objects[aip->target_objnum], aip->targeted_subsys)));
+	return ade_set_args(L, "o", l_Subsystem.Set(ship_subsys_h(aip->target_objnum >= 0 ? &Objects[aip->target_objnum] : nullptr, aip->targeted_subsys)));
 }
 
 ADE_VIRTVAR(Team, l_Ship, "team", "Ship's team", "team", "Ship team, or invalid team handle if ship handle is invalid")

code/ship/ship.cpp

@@ -2557,7 +2557,7 @@ particle::ParticleEffectHandle create_ship_legacy_particle_effect(LegacyShipPart
 	}
 
 	if (velocity_curve) {
-		effect.m_modular_curves.add_curve("Trigger Velocity", particle::ParticleEffect::ParticleCurvesOutput::VOLUME_VELOCITY_MULT, *radius_curve);
+		effect.m_modular_curves.add_curve("Trigger Velocity", particle::ParticleEffect::ParticleCurvesOutput::VOLUME_VELOCITY_MULT, *velocity_curve);
 	}
 
 	return particle::ParticleManager::get()->addEffect(std::move(effect));