https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87091
--- Comment #6 from David Malcolm <dmalcolm at gcc dot gnu.org> --- I've been using this PR to track various tweaks to how we print that fix-it hint. As well as the bug fix referred to in comment #1, we've gone from: In file included from ../x86_64-pc-linux-gnu/libstdc++-v3/include/debug/vector:34, from /tmp/t.cc:2: ../x86_64-pc-linux-gnu/libstdc++-v3/include/vector:87:27: error: ‘vector’ in namespace ‘std’ does not name a template type 87 | using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>; | ^~~~~~ ../x86_64-pc-linux-gnu/libstdc++-v3/include/vector:87:22: note: ‘std::vector’ is defined in header ‘<vector>’; did you forget to ‘#include <vector>’? ../x86_64-pc-linux-gnu/libstdc++-v3/include/vector:74:1: ++ |+#include <vector> 74 | #endif ../x86_64-pc-linux-gnu/libstdc++-v3/include/vector:87:22: 87 | using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>; | ^~~ to: In file included from ../x86_64-pc-linux-gnu/libstdc++-v3/include/debug/vector:34, from /tmp/t.cc:2: ../x86_64-pc-linux-gnu/libstdc++-v3/include/vector:87:27: error: ‘vector’ in namespace ‘std’ does not name a template type 87 | using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>; | ^~~~~~ ../x86_64-pc-linux-gnu/libstdc++-v3/include/vector:74:1: note: ‘std::vector’ is defined in header ‘<vector>’; did you forget to ‘#include <vector>’? 73 | # include <debug/vector> ++ |+#include <vector> 74 | #endif I think that's all for now.