This is very harmful and might cost you your life.
Bleach is made with a compound called Sodium Hypochlorite. The most commonly used compound in Toilet cleaners is Hydrochloric acid.
When these chemicals are mixed, a reaction creates toxic chloramine gases. Bleach and toilet cleaner may unintentionally be mixed by using the same cleaning cloth for multiple products, cleaning surfaces with multiple products or pouring bleach water down a drain after toilet cleaner was used, Chloramine gas is created almost instantly when bleach and toilet cleaner are mixed. Negative health effects can begin in minutes after the gas is dispersed in the air; the length of time before these negative effects occur depends on ventilation, concentration of bleach and toilet cleaner and the amount of water diluting the mixture.
The fumes can cause skin, eye and nose irritation, vomiting, pneumonia and fluid in the lungs. In higher concentrations, gaseous chlorine irritates eyes and skin. If the concentration is high enough, inhalation of chloramine gas can cause death.

Always store cleaning products in their original containers and never remove their labels. This will help reduce the risk of mixing cleaning products that contain bleach with toilet cleaner. Read labels and follow all the recommendations and warnings. Consider switching to natural cleaning solutions to reduce the use of toxic chemicals.
Read the labels of all cleaning products so you know which ones contain bleach. If you clean a surface with a product that contains bleach or toilet cleaner, make sure the surface is completely rinsed and dried before using another product. Use a different cleaning cloth for bleach and toilet cleaner to prevent chemicals from mixing on the cloths. Rinse cleaning cloths before putting them in the washing machine, Aside gas evolution, it is risky especially when used on the toilet bowl.

