Clang appears to be a bit picky wrt the relative order of annotation
notations here, and complains
/home/sberg/gcc/inst/lib/gcc/x86_64-pc-linux-gnu/15.0.0/../../../../include/c++/15.0.0/bits/stl_iter
ator.h:1080:42: error: an attribute list cannot appear here
1080 | __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
| ^~~~~~~~~~~~~~~~~~
/home/sberg/gcc/inst/lib/gcc/x86_64-pc-linux-gnu/15.0.0/../../../../include/c++/15.0.0/x86_64-pc-linux-gnu/bits/c++config.h:173:29:
note: expanded from macro '_GLIBCXX_NODISCARD'
173 | # define _GLIBCXX_NODISCARD [[__nodiscard__]]
| ^~~~~~~~~~~~~~~~~
which would be trivially solved by something like
diff --git a/libstdc++-v3/include/bits/stl_iterator.h
b/libstdc++-v3/include/bits/stl_iterator.h
index 26c5eab4b4e..49d03188fda 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -1077,13 +1077,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Forward iterator requirements
- __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
+ _GLIBCXX_NODISCARD __attribute__((__always_inline__))
_GLIBCXX_CONSTEXPR
reference
operator*() const _GLIBCXX_NOEXCEPT
{ return *_M_current; }
- __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
+ _GLIBCXX_NODISCARD __attribute__((__always_inline__))
_GLIBCXX_CONSTEXPR
pointer
operator->() const _GLIBCXX_NOEXCEPT
@@ -1123,7 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Random access iterator requirements
- __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
+ _GLIBCXX_NODISCARD __attribute__((__always_inline__))
_GLIBCXX_CONSTEXPR
reference
operator[](difference_type __n) const _GLIBCXX_NOEXCEPT
@@ -1135,7 +1135,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
operator+=(difference_type __n) _GLIBCXX_NOEXCEPT
{ _M_current += __n; return *this; }
- __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
+ _GLIBCXX_NODISCARD __attribute__((__always_inline__))
_GLIBCXX_CONSTEXPR
__normal_iterator
operator+(difference_type __n) const _GLIBCXX_NOEXCEPT
@@ -1147,13 +1147,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
{ _M_current -= __n; return *this; }
- __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
+ _GLIBCXX_NODISCARD __attribute__((__always_inline__))
_GLIBCXX_CONSTEXPR
__normal_iterator
operator-(difference_type __n) const _GLIBCXX_NOEXCEPT
{ return __normal_iterator(_M_current - __n); }
- __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
+ _GLIBCXX_NODISCARD __attribute__((__always_inline__))
_GLIBCXX_CONSTEXPR
const _Iterator&
base() const _GLIBCXX_NOEXCEPT
