New Syntax: type alias / type A[T] = X (Python 3.12) #852

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1. lieryan

   changed the title [-]New Syntax: `type` keyword[/-] [+]New Syntax: `type` keyword (Python 3.12)[/+] on Aug 12, 2026
2. lieryan

   added a sub-issue on Aug 12, 2026

   • Support TypeAlias ast nodes #821
3. lieryan

   linked a pull request that will close this issueImplement patchedast for TypeAlias and TypeVar/TypeVar/ParamSpec syntax #854on Aug 16, 2026
4. lieryan

   closed this as completedin #854on Aug 16, 2026
5. lieryan

   reopened this on Aug 16, 2026
6. lieryan

   changed the title [-]New Syntax: `type` keyword (Python 3.12)[/-] [+]New Syntax: type alias / `type A[T] = X` (Python 3.12)[/+] on Aug 20, 2026
7. lieryan

   added a sub-issue on Aug 20, 2026

   • Rename and inline refactor did not recognize type alias statements as variable assignment #862
8. mcepl commented on Nov 2, 2026

   

   mcepl

   on Nov 2, 2026

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   @lieryan The patchedast part is done and released in 1.15.0. #854 added TypeAlias, and #845 added type parameters on aliases. get_patched_ast() handles both type Alias = int and type ListOf[T] = list[T], and write_ast() reproduces the source exactly.

   What's left is name resolution. Rename refuses Alias with "should be performed on resolvable python identifiers". That's #862, which PR #874 fixes. #874 deliberately leaves out renaming the alias's own type parameter, because that needs a scope for the alias. Should that become a separate sub-issue here, so this can be closed once #874 is merged?