Skip to content

Update unreachable.rst: mention match exhaustiveness codes from checkers type … #2062

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 8, 2025
Merged

Update unreachable.rst: mention match exhaustiveness codes from checkers type … #2062

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
bad7ee2
Update unreachable.rst: mention match exhaustiveness codes from type …
wyattscarpenter Aug 2, 2025
02883f7
Update docs/guides/unreachable.rst: commit suggestion
wyattscarpenter Aug 8, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 8 additions & 0 deletions docs/guides/unreachable.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,14 @@ and is also present in ``typing_extensions`` starting at version 4.1.
However, it is also possible to define a similar function in your own
code, for example if you want to customize the runtime error message.

This use of match statements for comprehensive matching is common
enough that some typecheckers have direct support for checking all match
statements for exhaustiveness, regardless of whether or not they have an
``assert_never``-style function in their default arm. For instance, in pyright
this can be enabled by enabling the diagnostic code ``reportMatchNotExhaustive``
(on by default in strict mode), and in mypy it can be enabled by enabling
the error code ``exhaustive-match``.

You can also use ``assert_never()`` with a sequence of ``if`` statements:

.. code:: python
Expand Down