[Bug c++/89336] internal compiler error when compiling a constexpr function

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89336

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
    r[i + 'a'] = i + 10;
    r[i + 'A'] = i + 10;
or
    r[i + 'a'] = i + 10;
    r[i + 'A'] = r[i + 'a'];
doesn't ICE.