https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72786
--- Comment #5 from David Malcolm <dmalcolm at gcc dot gnu.org> --- Author: dmalcolm Date: Tue Nov 21 00:40:53 2017 New Revision: 254978 URL: https://gcc.gnu.org/viewcvs?rev=254978&root=gcc&view=rev Log: C++: provide macro used-before-defined hint (PR c++/72786) This patch uses the name_hint/deferred_diagnostic to provide a message in the C++ frontend if a macro is used before it is defined e.g.: test.c:6:24: error: expected ';' at end of member declaration virtual void clone() const OVERRIDE { } ^~~~~ ; test.c:6:30: error: 'OVERRIDE' does not name a type virtual void clone() const OVERRIDE { } ^~~~~~~~ test.c:6:30: note: the macro 'OVERRIDE' had not yet been defined test.c:15:0: note: it was later defined here #define OVERRIDE override It's possible to do it from the C++ frontend as tokenization happens up-front (and hence the macro already exists when the above is parsed); I attempted to do it from the C frontend, but because the C frontend only tokenizes on-demand during parsing, the macro isn't known about until later. gcc/cp/ChangeLog: PR c++/72786 * name-lookup.c (class macro_use_before_def): New class. (lookup_name_fuzzy): Detect macro that were used before being defined, and report them as such. gcc/ChangeLog: PR c++/72786 * spellcheck.h (best_match::blithely_get_best_candidate): New accessor. gcc/testsuite/ChangeLog: PR c++/72786 * g++.dg/spellcheck-macro-ordering-2.C: New test case. * g++.dg/spellcheck-macro-ordering.C: Add dg-message directives for macro used-before-defined. libcpp/ChangeLog: PR c++/72786 * include/cpplib.h (cpp_macro_definition_location): New decl. * macro.c (cpp_macro_definition): New function. Added: trunk/gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C Modified: trunk/gcc/ChangeLog trunk/gcc/cp/ChangeLog trunk/gcc/cp/name-lookup.c trunk/gcc/spellcheck.h trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/g++.dg/spellcheck-macro-ordering.C trunk/libcpp/ChangeLog trunk/libcpp/include/cpplib.h trunk/libcpp/macro.c
