From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1734) id 6606238582A1; Thu, 2 Mar 2023 16:02:08 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6606238582A1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1677772928; bh=oza4WpRdKxLNA3udQsQSaDSbwb0ZiVFOtX0LWckree4=; h=From:To:Subject:Date:From; b=LJ9iBIdEU4SNra3VPh3qVTHz1yKIhwqSvqI+PKMVcy43b7VmZey/MJRS8FyoIMtYd cIeSU7urIPlLll2r1i1qo4+8bsMIykg5Mx0DmpXoEc09rhs8YlGW9uua8+TIAS4iyd 6WyIMfsL6T/BtmopmBaB/UxAs4Xa2XwqZXMAwWvY= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Marek Polacek To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-6417] c++: ICE with -Wmismatched-tags and member template [PR106259] X-Act-Checkin: gcc X-Git-Author: Marek Polacek X-Git-Refname: refs/heads/trunk X-Git-Oldrev: da19e37cedc2acd1c560012dc41a57b7145dc181 X-Git-Newrev: 71afd0628419c5d670701cb35bc9860380c7d9fb Message-Id: <20230302160208.6606238582A1@sourceware.org> Date: Thu, 2 Mar 2023 16:02:08 +0000 (GMT) List-Id: https://gcc.gnu.org/g:71afd0628419c5d670701cb35bc9860380c7d9fb commit r13-6417-g71afd0628419c5d670701cb35bc9860380c7d9fb Author: Marek Polacek Date: Wed Mar 1 14:28:46 2023 -0500 c++: ICE with -Wmismatched-tags and member template [PR106259] -Wmismatched-tags warns about the (harmless) struct/class mismatch. For, e.g., template struct A { }; class A a; it works by adding A to the class2loc hash table while parsing the class-head and then, while parsing the elaborate type-specifier, we add A. At the end of c_parse_file we go through the table and warn about the class-key mismatches. In this PR we crash though; we have template struct A { template struct W { }; }; struct A::W w; // #1 where while parsing A and #1 we've stashed A A::W A::W into class2loc. Then in class_decl_loc_t::diag_mismatched_tags TYPE is A::W, and specialization_of gets us A::W, which is not in class2loc, so we crash on gcc_assert (cdlguide). But it's OK not to have found A::W, we should just look one "level" up, that is, A::W. It's important to handle class specializations, so e.g. template<> struct A { template class W { }; }; where W's class-key is different than in the primary template above, so we should warn depending on whether we're looking into A or into a different instantiation. PR c++/106259 gcc/cp/ChangeLog: * parser.cc (class_decl_loc_t::diag_mismatched_tags): If the first lookup of SPEC didn't find anything, try to look for most_general_template. gcc/testsuite/ChangeLog: * g++.dg/warn/Wmismatched-tags-11.C: New test. Diff: --- gcc/cp/parser.cc | 30 ++++++++++++++++++++----- gcc/testsuite/g++.dg/warn/Wmismatched-tags-11.C | 23 +++++++++++++++++++ 2 files changed, 47 insertions(+), 6 deletions(-) diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 3d6b8f252a3..b00a6cd5b8b 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -34473,14 +34473,32 @@ class_decl_loc_t::diag_mismatched_tags (tree type_decl) be (and inevitably is) at index zero. */ tree spec = specialization_of (type); cdlguide = class2loc.get (spec); + /* It's possible that we didn't find SPEC. Consider: + + template struct A { + template struct W { }; + }; + struct A::W w; // #1 + + where while parsing A and #1 we've stashed + A + A::W + A::W + into CLASS2LOC. If TYPE is A::W, specialization_of + will yield A::W which may be in CLASS2LOC if we had + an A class specialization, but otherwise won't be in it. + So try to look up A::W. */ + if (!cdlguide) + { + spec = DECL_TEMPLATE_RESULT (most_general_template (spec)); + cdlguide = class2loc.get (spec); + } + /* Now we really should have found something. */ gcc_assert (cdlguide != NULL); } - else - { - /* Skip declarations that consistently use the same class-key. */ - if (def_class_key != none_type) - return; - } + /* Skip declarations that consistently use the same class-key. */ + else if (def_class_key != none_type) + return; /* Set if a definition for the class has been seen. */ const bool def_p = cdlguide->def_p (); diff --git a/gcc/testsuite/g++.dg/warn/Wmismatched-tags-11.C b/gcc/testsuite/g++.dg/warn/Wmismatched-tags-11.C new file mode 100644 index 00000000000..6c4e571726a --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Wmismatched-tags-11.C @@ -0,0 +1,23 @@ +// PR c++/106259 +// { dg-do compile } +// { dg-options "-Wmismatched-tags" } + +template struct A { + template + struct W { }; +}; + +template<> +struct A { + template + class W { }; +}; + +void +g () +{ + struct A::W w1; // { dg-warning "mismatched" } + struct A::W w2; + class A::W w3; + class A::W w4; // { dg-warning "mismatched" } +}