http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55203
Bug #: 55203 Summary: No unused warning for variables of non-trivial types Classification: Unclassified Product: gcc Version: 4.8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: l.lu...@suse.cz GCC warns about unused variables e.g. of type 'int', but not 'std::string' : $ cat a.cpp #include <string> void foo() { int i; std::string s; } $ g++ -Wall -Wunused -c a.cpp a.cpp: In function ‘void foo()’: a.cpp:5:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ In the function 's' is apparently unused too, but the compiler cannot tell it.