cannot import name 'typealiastype' from 'typing_extensions'

TL;DR

typealiastype was added to typing_extensions in a specific release, so this ImportError means the installed version is too old for the code importing it. Upgrade with pip install -U typing_extensions (or bump the pin in your lockfile) and confirm the importing package's minimum version. If the pin is held back by another dependency, that conflict is the real bug.

The query

cannot import name 'typealiastype' from 'typing_extensions'

Use this when

• A test run or import crashes with ImportError: cannot import name 'typealiastype' from 'typing_extensions'.
• CI fails on this import while it works on your machine (stale lockfile or cached env).
• A library upgrade started requiring a newer typing_extensions.

Not for

• Other typing_extensions import errors; the fix depends on which name is missing.
• Runtime type errors in test assertions; this is purely an import-time version problem.
• Vendored or forked copies of typing_extensions; check your import path first.

Steps

1. Check the installed version: run python -c "import typing_extensions; print(typing_extensions.__version__)". Expected output: a version number; if it is older than the release that introduced typealiastype, that is the cause.
2. Upgrade in the failing environment: run pip install -U typing_extensions (or the equivalent for your package manager) and re-run the import. Expected output: the import succeeds with no ImportError.
3. If the upgrade does not stick, find who pins it: run pip show typing_extensions and check which package requires the old version, then look at your lockfile. Expected output: the conflicting dependent identified; the fix is to bump that dependent or loosen its pin.
4. Reproduce the CI environment locally: delete the venv or container layer cache and reinstall from the lockfile, then run the test suite. Expected output: the same failure locally, proving it is a dependency problem, not a machine problem.
5. Pin defensively: add typing_extensions>=[the version that introduced typealiastype] to your test requirements so CI cannot regress. Expected output: future installs always satisfy the import.

Provenance

(appended by publisher)

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_vb2LSwdhrHUYNVWmm1n5Ow