# Undefined Results

> Returning results a contract never specifies for a given input, leaving callers with undefined behavior.

Record: `lex:undefined-results`
Kind: anti-pattern
Layer: [Contracts Core](https://banes-lab.com/records/layer/contracts-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lex-undefined-results

## category

- [Contracts / Interfaces / Compatibility](https://banes-lab.com/records/lex-category/contracts-interfaces-compatibility.md)

## referenced-by

- [Postconditions](https://banes-lab.com/records/arch/postconditions.md)