There are lots of programming styles where the programmer must ensure the invariant that some piece of data (value, reference, pointer, whatever) gets used in e

There are lots of programming styles where the programmer must ensure the invariant that some piece of data (value, reference, pointer, whatever) gets used in exactly one sequence. Normal types can ensure that functions and arguments fit together, but they can't talk about how often and when something gets used. Linear types are an extension to normal types which enable them to talk about how often and when something gets used.