# Type checking only typed input

**URL:** <https://discuss.python.org/t/type-checking-only-typed-input/102570>\
**Category:** Typing\
**Created:** [August 16, 2025, 2:59pm UTC](https://discuss.python.org/t/type-checking-only-typed-input/102570 "2025-08-16T14:59:48Z")\
**Posts on this page:** 1\
**Showing post:** 17

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**Author:** ![Jelle](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/jelle/32/1049_2.png) [@Jelle](https://discuss.python.org/u/Jelle)\
**Post date:** [August 19, 2025, 3:28pm UTC](https://discuss.python.org/t/type-checking-only-typed-input/102570/17 "2025-08-19T15:28:26Z")

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`@deprecated` does probably do what you want here, in terms of producing type checker diagnostics for code that you want to produce diagnostics. It’s conceptually not a great fit though because nothing is actually deprecated here. This might confuse users, and means that type checker configurations would work in unintuitive ways.

There’s a [longstanding idea](https://github.com/python/typing/issues/1043) to add something like a `@typing_error` decorator that would work similar to `@deprecated` but not carry any implications about deprecation. I included that in an early version of PEP 702 but removed it for simplicity. However, new use cases keep coming up, so now may be a good time for a new PEP proposing this idea.

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