Origins
The rules on pre- and postconditions are identical to those introduced by Bertrand Meyer in his 1988 book. Both Meyer, and later Pierre America, who was the first to use the term behavioral subtyping, gave proof-theoretic definitions of some behavioral subtyping notions, but their definitions did not take into account aliasing that may occur in programming language that supports references or pointers. Taking aliasing into account was the major improvement made by Liskov and Wing (1994), and a key ingredient is the history constraint. Under the definitions of Meyer and America a MutablePoint would be a behavioral subtype of ImmutablePoint, whereas LSP forbids this.
Read more about this topic: Liskov Substitution Principle
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