My understanding of the paper is that we just want to promote the CPP_WCHAR
"character constant too long for its type" warning to error as it is already
error for u8, u and U literals.
2022-08-26 Jakub Jelinek <jakub@redhat.com>
PR c++/106647
* charset.cc (wide_str_to_charconst): Implement P2362R3 - Remove
non-encodable wide character literals and multicharacter. For
C++23 use CPP_DL_ERROR instead of CPP_DL_WARNING for
"character constant too long for its type" diagnostics on CPP_WCHAR
literals.
* g++.dg/cpp23/wchar-multi1.C: New test.
* g++.dg/cpp23/wchar-multi2.C: New test.
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