https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104640
--- Comment #3 from Paco Arjonilla <pacoarjonilla at yahoo dot es> ---
(In reply to Paco Arjonilla from comment #2)
Compiler output:
<source>:4:17: error: pasting """_" and "\U000000b5m" does not give a valid
preprocessing token
4 | double operator ""_##suffix (long long unsigned arg) \
| ^~~
<source>:11:1: note: in expansion of macro 'MACRO'
11 | MACRO(µm) // <-- COMPILATION ERROR (should compile)
| ^~~~~
<source>:11:7: error: expected initializer before '\U000000b5m'
11 | MACRO(µm) // <-- COMPILATION ERROR (should compile)
| ^~
<source>:4:22: note: in definition of macro 'MACRO'
4 | double operator ""_##suffix (long long unsigned arg) \
| ^~~~~~
