Able to get cheats in survival without switching on cheats in the settings

When i was playing survival i cassualy went into the chat and typed the slash symbol ( / ) in my survival world with cheats of in my settings and the i typed give /give@s diamond 64 (see there is no space after give and before @s) it actually gave me diamonds 

HOW TO REPRODUCE:-

->go into survival world with cheats off

->open chat 

->and type any cheat such as /give and then without any space after /give type @s and type the object you want and you will get the  specific object

 Credits to skippy 6 gaming for the pics (you can see his youtube vedio)