PR c++/86329 reports that the C++ frontend can offer bogus suggestions like:
#include <string> int compare() { return __n1 - __n2; } suggested.cc: In function 'int compare()': suggested.cc:5:10: error: '__n1' was not declared in this scope return __n1 - __n2; ^~~~ suggested.cc:5:10: note: suggested alternative: '._61' return __n1 - __n2; ^~~~ ._61 suggested.cc:5:17: error: '__n2' was not declared in this scope return __n1 - __n2; ^~~~ suggested.cc:5:17: note: suggested alternative: '._72' return __n1 - __n2; ^~~~ ._72 The dot-prefixed names are an implementation detail of how we implement anonymous enums found in the header files, generated via anon_aggrname_format in make_anon_name. This patch uses anon_aggrname_p to filter them out when considering which names to suggest. Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu; adds 9 PASS results to g++.sum OK for trunk, gcc-8, gcc-7 branches? gcc/cp/ChangeLog: PR c++/86329 * name-lookup.c (consider_binding_level): Filter out names that match anon_aggrname_p. gcc/testsuite/ChangeLog: PR c++/86329 * g++.dg/lookup/pr86329.C: New test. --- gcc/cp/name-lookup.c | 5 +++++ gcc/testsuite/g++.dg/lookup/pr86329.C | 11 +++++++++++ 2 files changed, 16 insertions(+) create mode 100644 gcc/testsuite/g++.dg/lookup/pr86329.C diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c index a30c374..6ec4e6e 100644 --- a/gcc/cp/name-lookup.c +++ b/gcc/cp/name-lookup.c @@ -5786,6 +5786,11 @@ consider_binding_level (tree name, best_match <tree, const char *> &bm, if (!suggestion) continue; + /* Don't suggest names that are for anonymous aggregate types, as + they are an implementation detail generated by the compiler. */ + if (anon_aggrname_p (suggestion)) + continue; + const char *suggestion_str = IDENTIFIER_POINTER (suggestion); /* Ignore internal names with spaces in them. */ diff --git a/gcc/testsuite/g++.dg/lookup/pr86329.C b/gcc/testsuite/g++.dg/lookup/pr86329.C new file mode 100644 index 0000000..fc091ba --- /dev/null +++ b/gcc/testsuite/g++.dg/lookup/pr86329.C @@ -0,0 +1,11 @@ +/* PR c++/86329: ensure we don't erroneously offer suggestions like "._0", + which are an implementation detail of how e.g. anonymous enums are + handled internally. */ + +enum {NONEMPTY}; + +int test() +{ + return __0; // { dg-error "'__0' was not declared in this scope" } + // { dg-bogus "suggested alternative" "" { target *-*-* } .-1 } +} -- 1.8.5.3