From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1888) id B5E3F385AC32; Tue, 11 Jan 2022 18:00:57 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B5E3F385AC32 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Patrick Palka To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-6485] c++: dependent bases and 'this' availability [PR103831] X-Act-Checkin: gcc X-Git-Author: Patrick Palka X-Git-Refname: refs/heads/master X-Git-Oldrev: 46de918f9892e637845bd97b4ca95011d46d3733 X-Git-Newrev: 0378f563b0321c44c4a9c98cf46d2a22b9160f76 Message-Id: <20220111180057.B5E3F385AC32@sourceware.org> Date: Tue, 11 Jan 2022 18:00:57 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Jan 2022 18:00:57 -0000 https://gcc.gnu.org/g:0378f563b0321c44c4a9c98cf46d2a22b9160f76 commit r12-6485-g0378f563b0321c44c4a9c98cf46d2a22b9160f76 Author: Patrick Palka Date: Tue Jan 11 13:00:48 2022 -0500 c++: dependent bases and 'this' availability [PR103831] Here during satisfaction of B's constraints we're failing to reject the object-less call to the non-static member function A::size ultimately because satisfaction is performed in the (access) context of the class template B, which has a dependent base, and so the any_dependent_bases_p check within build_new_method_call causes us to not reject the call. (Subsequent constexpr evaluation of the call succeeds since the function is effectively static.) This patch fixes this by refining the any_dependent_bases_p check within build_new_method_call: if we're in a context where 'this' is unavailable, then we cannot resolve the implicit object regardless of the presence of a dependent base. So let's also check current_class_ptr alongside a_d_b_p. PR c++/103831 gcc/cp/ChangeLog: * call.c (build_new_method_call): Consider dependent bases only if 'this' is available. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-class3.C: New test. * g++.dg/template/non-dependent18.C: New test. Diff: --- gcc/cp/call.c | 2 +- gcc/testsuite/g++.dg/cpp2a/concepts-class3.C | 12 ++++++++++++ gcc/testsuite/g++.dg/template/non-dependent18.C | 19 +++++++++++++++++++ 3 files changed, 32 insertions(+), 1 deletion(-) diff --git a/gcc/cp/call.c b/gcc/cp/call.c index 88ab23392d2..d4a07a7a9b3 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -11125,7 +11125,7 @@ build_new_method_call (tree instance, tree fns, vec **args, we know we really need it. */ cand->first_arg = instance; } - else if (any_dependent_bases_p ()) + else if (current_class_ptr && any_dependent_bases_p ()) /* We can't tell until instantiation time whether we can use *this as the implicit object argument. */; else diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-class3.C b/gcc/testsuite/g++.dg/cpp2a/concepts-class3.C new file mode 100644 index 00000000000..68b50b71278 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-class3.C @@ -0,0 +1,12 @@ +// PR c++/103831 +// { dg-do compile { target c++20 } } + +struct A { + constexpr int size() { return 42; } // non-static +}; + +template + requires (T::size() == 42) // { dg-error "without object" } +struct B : T { }; + +template struct B; // { dg-error "constraint" } diff --git a/gcc/testsuite/g++.dg/template/non-dependent18.C b/gcc/testsuite/g++.dg/template/non-dependent18.C new file mode 100644 index 00000000000..3e1556821a6 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/non-dependent18.C @@ -0,0 +1,19 @@ +// PR c++/103831 +// { dg-do compile { target c++11 } } + +struct A { + constexpr int size() { return 42; } // non-static +}; + +template +struct B : T { + static_assert(A::size() == 42, ""); // { dg-error "without object" } + + static int f() { + static_assert(A::size() == 42, ""); // { dg-error "without object" } + return A::size(); // { dg-error "without object" } + } + + int n = A::size(); + static const int m = A::size(); // { dg-error "without object" } +};