Here’s a weird vendor divergence recently spotted on the cpplang Slack.
Consider a function template foo, where instantiating the body of
foo<int> will give an error. For example:

Authored by Arthur O'Dwyer, Quuxplusone offers  explorations of C++ programming language features, standard library design, and modern C++ development practices. Readers can delve into advanced topics such as template metaprogramming, design patterns, and effective use of language features. Additionally, they can learn about best practices for writing efficient and maintainable C++ code, optimizing performance, and leveraging the latest language standards.

Arthur O'Dwyer

A deep dive into compiler divergence when handling unevaluated lambdas with capture-lists that call invalid-to-instantiate function templates. Clang and GCC disagree on when to instantiate function bodies: Clang rejects lambda-expressions but accepts equivalent struct types, while GCC does the opposite. EDG and MSVC accept both. The article also covers CWG2518, which made non-dependent static_assert legal in uninstantiated templates as of 2023.

Divergence in instantiating unused functions of unevaluated lambdas