Potential GCC 16 bug: annotations disappear on nested class declarations inside class templates

Im playing around with reflection (GCC16) and I ran into the following problem:

When using `std::meta::define_aggregate`to complete an annotated nested class, the annotation is removed, iff the enclosing class is templated.

Below is a minimal reproducible example ([Godbolt link](https://godbolt.org/z/dGTsea7ad)).

I would expect both assertions to succeed, but they don't. There is also [GCC PR124399](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124399), which addresses a related problem, but I'm not sure if this is the *same* underlying problem.

Is this a bug, or am I overlooking/misunderstanding some template instantiation rules?

#include <meta>

// Works: ordinary forward declaration.
struct [[=42]] Ordinary;
static_assert(std::meta::annotations_of(^^Ordinary).size() == 1);

// Fails: forward declaration inside a class template.
template <typename T>
struct Outer {
struct [[=42]] Inner;
};

static_assert(sizeof(Outer<int>) > 0);
static_assert(std::meta::annotations_of(^^Outer<int>::Inner).size() == 1);

**Context:** I'm experimenting with rust-like `derive(debug)` functionality using annotations, combined with structural type transformations (similar to AoS to SoA). I originally encountered this while trying to propagate annotations to a generated type, before reducing it to the example above.

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CLI library v. 2.3 released
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There is definitely some cool stuff this lets us do a bit more of - high level planning and systems design by reading many papers as well as exploring formal verification.
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hpx.dev – The documentation and community portal for the HPX project

Sharing **https://hpx.dev**, the central web portal for the open-source HPX C++ runtime.

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Official Documentation: Direct, searchable access to the HPX API references and technical manuals.
Engineering Blog & Release Notes: Technical write-ups on architectural updates, subsystem integration, and project releases.
Contributor Reports: Detailed summaries from open-source contributors, including deep-dives into recent Google Summer of Code (GSoC) projects.
The "HPX In Action" Series: Ongoing interviews featuring developers, researchers, and contributors discussing their workflows and HPC challenges.

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Is there any point in improving the/any language at this point ?

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New C++ Conference Videos Released This Month - November 2026 (Updated To Include Videos Released 2026-11-02 - 2026-11-08)

C++Now

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Lightning Talk: The Hidden Superpower of Modern CPUs - Why ILP Can Make “More Work” Run Faster - Sampad Acharya - [https://youtu.be/WZl7tMBBn3U](https://youtu.be/WZl7tMBBn3U)
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ADC

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Are You Shipping Your Source Code? - Ryan Wardell - [https://youtu.be/ToPPQ6uTUJ0](https://youtu.be/ToPPQ6uTUJ0)
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TX/RX Part 2 - AI Audio on the Raspberry Pi - Kieran Coulter - https://youtu.be/QSiyLDHoBpo
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How does one actually contribute to LLVM these days?

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Patch 2) Someone responded that they were busy and would get around to it when they had a chance to. It’s been a few months and followed up in the comments to no response

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Hi,


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