Bullet 6.11 says:

A temporary bound to a reference in a new-initializer (8.3.4) persists until the completion of the full-expression containing the new-initializer. [Example:

struct S { int mi; const std::pair<int,int>& mp; };
S a { 1, {2,3} };
S* p = new S{ 1, {2,3} }; // Creates dangling reference

— end example ] [ Note: This may introduce a dangling reference, and implementations should issue a warning in such a case. — end note ]

Even if this note were sound advice (it is not in all cases: such a warning may have false positives if the allocation is consumed before the full-expression ends), providing normative encouragement via "should" in a note is verboten (ISO Directives, part 2, 7th ed, 24.5).