https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86273
Bug ID: 86273 Summary: confusing diagnostic for member-declaration with missing identifier Product: gcc Version: 8.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: nightstrike at gmail dot com Target Milestone: --- #include <vector> struct Input { std::vector<std::vector<float>>; }; $ g++ xxx.cc xxx.cc:4:7: error: a template-id may not appear in a using-declaration std::vector<std::vector<float>>; ^~~~~~~~~~~~~~~~~~~~~~~~~~ Perhaps this diagnostic could be worded better to clearly show the problem being the missing variable name.