[Bug c++/93191] New: Conversions to arrays of unknown bound P0388 Fails for variadic args

[wjwray at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93191

            Bug ID: 93191
           Summary: Conversions to arrays of unknown bound P0388 Fails for
                    variadic args
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: wjwray at gmail dot com
  Target Milestone: ---

The P0388 permitted conversion from array of known bound to
array-reference of unknown bound fails for variadic arguments
https://godbolt.org/z/Rp3GdN

    #include <cstdio>

    void cat(auto const(&...cstr)[]) { (((void)cstr,puts("G'bye")),...); }
    //void cat(auto const(&...cstr)[6]) { (puts(cstr),...); }

    using punk = char(*)[]; // Pointer to UNKnown-bound char array

    int main() {
        cat("Hello","world");  // error: no matching function
        cat(*punk{},*punk{});  // Matches 1st overload
    }

Same with explicit template syntax

    template <typename... C> void cat(C const(&...cstr)[]);