base::format does not accept rvalues, using the result of format_as directly means it is passed one. Doesn't matter for ranges with a const begin and end, but since std::ranges::filter_view caches the next value to return, it only has a mutable begin/end iterator.
If we just store the result of format_as in a temporary variable, we can pass it as an lvalue.
vitaut
commented
1 month ago
Fixes issue #3752
base::formatdoes not accept rvalues, using the result offormat_asdirectly means it is passed one. Doesn't matter for ranges with a const begin and end, but sincestd::ranges::filter_viewcaches the next value to return, it only has a mutable begin/end iterator.If we just store the result of
format_asin a temporary variable, we can pass it as an lvalue.Since we use it in https://github.com/fmtlib/fmt/blob/1dc71f21eadac50c85b5c840ca7db2bf7a507b15/include/fmt/ranges.h#L485-L490 And we don't call
std::forwardanyway, I don't think we're performing any pessimisation by making this changeAnother way to fix this is by providing a
&&overload of https://github.com/fmtlib/fmt/blob/1dc71f21eadac50c85b5c840ca7db2bf7a507b15/include/fmt/ranges.h#L541-L545 However other control paths (that pass lvalues) then flow through this, which doesn't seem right, so didn't opt for that method