[Bug ada/123306] assertion failure for unfrozen mutably tagged type as actual in instance

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123306

--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Eric Botcazou <ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:48db9b45057416ba3116fa9bc6e63ff13990c92d

commit r16-6403-g48db9b45057416ba3116fa9bc6e63ff13990c92d
Author: Eric Botcazou <ebotcazou@gcc.gnu.org>
Date:   Sat Dec 27 10:24:52 2025 +0100

    Ada: Fix assertion failure for unfrozen mutably tagged type as actual

    ...in instance.  An instantiation is a freezing point for the actuals,
    so the mutably tagged type will be frozen by the instantiation, but this
    happens too late in the current implementation of mutably tagged types,
    because the declaration of their CW-equivalent type is not analyzed until
    after the type is frozen.

    gcc/ada/
            PR ada/123306
            * sem_ch12.adb (Analyze_One_Association): Immediately freeze the
            root type of mutably tagged types used as actual type parameters.

    gcc/testsuite/
            * gnat.dg/specs/mutably_tagged1.ads: New test.