[Bug c++/113127] New: Unexpected error: '' was not declared 'constexpr'

[fchelnokov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113127

            Bug ID: 113127
           Summary: Unexpected error: '<anonymous>' was not declared
                    'constexpr'
           Product: gcc
           Version: 13.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fchelnokov at gmail dot com
  Target Milestone: ---

This constexpr variable definition

    constexpr bool b = ( delete [][]{ return new int[2]; }(), true );

is accepted in Clang and MSVC. But GCC complains:

    <source>:1:64: error: the value of '<anonymous>' is not usable in a
constant 
    <source>:1:56: note: '<anonymous>' was not declared 'constexpr'

Online demo: https://godbolt.org/z/ovso3neEr