[gcc r13-9478] libstdc++: Cast -1 to size_t in <format> [PR119429]

[Jonathan Wakely]

https://gcc.gnu.org/g:1662a95371061018415ef26c2e787451c420aa56

commit r13-9478-g1662a95371061018415ef26c2e787451c420aa56
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Mar 24 21:25:20 2025 +0000

    libstdc++: Cast -1 to size_t in <format> [PR119429]
    
    This avoids a runtime error from Clang's annoying -fsanitize=integer
    (even though it's not undefined and behaves correctly).
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/119429
            * include/std/format (__format::_Scanner::_Scanner): Cast
            default argument to size_t.
    
    (cherry picked from commit 039cc50867000e6427924ca490dc810eaa44cf08)

Diff:
---
 libstdc++-v3/include/std/format | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format
index 3c9b5a088a3f..26e87c427afd 100644
--- a/libstdc++-v3/include/std/format
+++ b/libstdc++-v3/include/std/format
@@ -3513,7 +3513,7 @@ namespace __format
       basic_format_parse_context<_CharT> _M_pc;
 
       constexpr explicit
-      _Scanner(basic_string_view<_CharT> __str, size_t __nargs = -1)
+      _Scanner(basic_string_view<_CharT> __str, size_t __nargs = (size_t)-1)
       : _M_pc(__str, __nargs)
       { }