[Clang][C++26] Raw string literals with newly perimitted d-chars are still rejected (original) (raw)

https://clang.llvm.org/cxx_status.html currently claims that P2558R2 is implemented. However, per [lex.string], @, $, and ` need to be usable as d-chars since C++26, and Clang doesn't accept the newly permitted raw string literals yet.

Godbolt link

int main() { (void) R"abc@$(foobar)abc@$"; }

Perhaps we should add pedantic warning/error for these permitted raw string literals in pre-C++26 modes.

Originally discovered by @jakubjelinek in https://gcc.gnu.org/PR110343.