[Bug c++/62063] g++ disregards template specialization and skips try/catch blocks

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62063

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Ferenc Géczi from comment #0)
> Created attachment 33276 [details]
> Source code for reproducing the reported issue
> 
> g++ disregards that template specialization might happen in a different
> compilation unit. 

How is the compiler supposed to know that?

If you don't declare a specialization before it would be needed the compiler
will not use it, and the program has undefined behaviour.

> For comparison, clang++ works as expected with -O0, without the
> -fnon-callexceptions. 
> Although it has the same the behavior with higher optimization levels.

That should tell you your expectation is wrong.