From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 104217 invoked by alias); 4 Dec 2018 19:09:42 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 104107 invoked by uid 89); 4 Dec 2018 19:09:38 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 spammy= X-HELO: mail-oi1-f170.google.com Received: from mail-oi1-f170.google.com (HELO mail-oi1-f170.google.com) (209.85.167.170) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 04 Dec 2018 19:09:35 +0000 Received: by mail-oi1-f170.google.com with SMTP id a77so15260875oii.5 for ; Tue, 04 Dec 2018 11:09:35 -0800 (PST) MIME-Version: 1.0 References: <20181128154849.GD3269@redhat.com> <51f04722-f35d-7df0-40a3-dc7926c82981@redhat.com> <20181129182828.GH3269@redhat.com> <5e3b0168-e98b-b9ac-e4da-a939b445ab98@redhat.com> <20181204172715.GK21364@redhat.com> In-Reply-To: <20181204172715.GK21364@redhat.com> From: Jason Merrill Date: Tue, 04 Dec 2018 19:09:00 -0000 Message-ID: Subject: Re: C++ PATCH for c++/88184, ICE when treating name as template-name To: Marek Polacek Cc: gcc-patches List Content-Type: text/plain; charset="UTF-8" X-IsSubscribed: yes X-SW-Source: 2018-12/txt/msg00225.txt.bz2 OK. On Tue, Dec 4, 2018 at 12:27 PM Marek Polacek wrote: > > On Thu, Nov 29, 2018 at 04:03:50PM -0500, Jason Merrill wrote: > > On 11/29/18 1:28 PM, Marek Polacek wrote: > > > On Wed, Nov 28, 2018 at 10:34:11PM -0500, Jason Merrill wrote: > > > > On 11/28/18 10:48 AM, Marek Polacek wrote: > > > > > Since P0846R0 was implemented, a name will be treated as a template-name when > > > > > it is an unqualified-id followed by a < and name lookup finds either one or > > > > > more functions or finds nothing, in order to potentially cause ADL to be performed. > > > > > > > > > > In this case, we had > > > > > > > > > > f (); > > > > > > > > > > where we'd found a decl for f (not a TEMPLATE_DECL) and < follows. > > > > > > > > From the backtrace in the PR, it seems as though we're treating f as > > > > non-dependent, which is wrong. type_dependent_expression_p only looks at > > > > the arguments of a TEMPLATE_ID_EXPR if it has unknown_type_node, so we > > > > probably want to give it that type. > > > > > > That was my first attempt but it was crashing everywhere, so I abandoned it. > > > But I was setting unknown_type_node in cp_parser_template_name whereas this > > > patch sets it in cp_parser_postfix_expression, which works and is arguably > > > better because it reuses the diagnostic in finish_call_expr. > > > > Would it work for lookup_template_function to always use unknown_type_node? > > Luckily, that seems to work! I wish I'd thought of that, I like fixing bugs by > simplifying code. > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > 2018-12-04 Marek Polacek > > PR c++/88184 - ICE when treating name as template-name. > * pt.c (lookup_template_function): Always build the TEMPLATE_ID_EXPR > with unknown_type_node. > > * g++.dg/cpp2a/fn-template17.C: New test. > * g++.dg/cpp2a/fn-template18.C: New test. > > diff --git gcc/cp/pt.c gcc/cp/pt.c > index a0d899f594b..78addc6c1c2 100644 > --- gcc/cp/pt.c > +++ gcc/cp/pt.c > @@ -9068,8 +9068,6 @@ add_pending_template (tree d) > tree > lookup_template_function (tree fns, tree arglist) > { > - tree type; > - > if (fns == error_mark_node || arglist == error_mark_node) > return error_mark_node; > > @@ -9090,11 +9088,7 @@ lookup_template_function (tree fns, tree arglist) > return fns; > } > > - type = TREE_TYPE (fns); > - if (TREE_CODE (fns) == OVERLOAD || !type) > - type = unknown_type_node; > - > - return build2 (TEMPLATE_ID_EXPR, type, fns, arglist); > + return build2 (TEMPLATE_ID_EXPR, unknown_type_node, fns, arglist); > } > > /* Within the scope of a template class S, the name S gets bound > diff --git gcc/testsuite/g++.dg/cpp2a/fn-template17.C gcc/testsuite/g++.dg/cpp2a/fn-template17.C > new file mode 100644 > index 00000000000..f0d24107682 > --- /dev/null > +++ gcc/testsuite/g++.dg/cpp2a/fn-template17.C > @@ -0,0 +1,21 @@ > +// PR c++/88184 > +// { dg-do compile } > +// { dg-options "-std=c++2a -fchecking=2" } > + > +namespace A > +{ > + void f (); > +} > + > +using A::f; > + > +template void g () > +{ > + f (); // { dg-error "no matching function for call" } > +} > + > +void > +fn () > +{ > + g(); > +} > diff --git gcc/testsuite/g++.dg/cpp2a/fn-template18.C gcc/testsuite/g++.dg/cpp2a/fn-template18.C > new file mode 100644 > index 00000000000..7fe5e89ace3 > --- /dev/null > +++ gcc/testsuite/g++.dg/cpp2a/fn-template18.C > @@ -0,0 +1,23 @@ > +// PR c++/88184 > +// { dg-do compile } > +// { dg-options "-std=c++2a -fchecking=2" } > + > +namespace A > +{ > + void f (); > + void f (int); > + void f (int, int); > +} > + > +using A::f; > + > +template void g () > +{ > + f (); // { dg-error "no matching function for call" } > +} > + > +void > +fn () > +{ > + g(); > +}