https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62116
Bug ID: 62116 Summary: Allowing redeclaration of global variable x using ::x Product: gcc Version: 4.9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: yaghmour.shafik at gmail dot com Given the following code: int x; int main() { int(::x); //does not compile int(::x + 2); //compiles } gcc 4.9 will compile it without an error while gcc 4.8.x and clang 3.4 will generate an error. For gcc 4.8.x the error is: error: invalid use of qualified-name '::x' int(::x); //does not compile ^ and clang gives the following error: error: definition or redeclaration of 'x' cannot name the global scope int(::x); //does not compile ~~^ as far as I can tell both gcc 4.8.x and clang are correct here based on my reading of section 8.3 paragraph 6: int(::x) ; is equivalent to: int ::x ; which is not valid. The problem originally cam up in the following Stackoverflow question: http://stackoverflow.com/questions/24623071/is-typex-valid