1 2 3 4 5 6 // Lots of vertical space to make the error line match up with the line of the 7 // expected line in the source file. 8 namespace warn_in_header_in_global_context {} 9 using namespace warn_in_header_in_global_context; 10 11 // While we want to error on the previous using directive, we don't when we are 12 // inside a namespace 13 namespace dont_warn_here { 14 using namespace warn_in_header_in_global_context; 15 } 16 17 // We should warn in toplevel extern contexts. 18 namespace warn_inside_linkage {} 19 extern "C++" { 20 using namespace warn_inside_linkage; 21 } 22 23 // This is really silly, but we should warn on it: 24 extern "C++" { 25 extern "C" { 26 extern "C++" { 27 using namespace warn_inside_linkage; 28 } 29 } 30 } 31 32 // But we shouldn't warn in extern contexts inside namespaces. 33 namespace dont_warn_here { 34 extern "C++" { 35 using namespace warn_in_header_in_global_context; 36 } 37 } 38 39 // We also shouldn't warn in case of functions. foo()40inline void foo() { 41 using namespace warn_in_header_in_global_context; 42 } 43 44 45 namespace macronamespace {} 46 #define USING_MACRO using namespace macronamespace; 47 48 // |using namespace| through a macro should warn if the instantiation is in a 49 // header. 50 USING_MACRO 51