https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88736
Bug ID: 88736 Summary: nullptr_t available without namespace qualification Product: gcc Version: 9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: drepper.fsp+rhbz at gmail dot com Target Milestone: --- I don't think the following should work and clang indeed complains. gcc 8.2.1 and current trunk both accept it without warning, even with -pedantic. #include <cstddef> int f(nullptr_t) { return 0; } Obviously gcc should recommend using std::nullptr_t.