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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/82833] [concepts] Out-of-line definition of nested class template errors with constraint (ICE) Date: Mon, 19 Jul 2021 10:04:55 +0000 [thread overview] Message-ID: <bug-82833-4-not0zJVCHM@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-82833-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82833 --- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- Looks like the ICE was fixed by the concepts rewrite in r10-3735 "Update the concepts implementation to conform to C++20." Valid C++20 testcase: #include <functional> #include <concepts> template <typename T, auto A, typename M> concept CallYieldsType = requires(T t) { { std::invoke(A, t) } -> std::same_as<M>; }; template <typename T> struct S { struct Z; template <auto A> requires CallYieldsType<T, A, Z> struct N; }; template <typename T> template <auto A> requires CallYieldsType<T, A, typename S<T>::Z> struct S<T>::N { Z &f(T t) { return std::invoke(A, t); } }; Bisections shows this started to be accepted with r11-3713: c++: Set the constraints of a class type sooner [PR96229] In the testcase below, during processing (at parse time) of Y's base class X<Y>, convert_template_argument calls is_compatible_template_arg to check if the template argument Y is no more constrained than the parameter P. But at this point we haven't yet set Y's constraints, so get_normalized_constraints_from_decl yields NULL_TREE as the normal form and caches this result into the normalized_map. We set Y's constraints later in cp_parser_class_specifier_1 but the stale normal form in the normalized_map remains. This ultimately causes us to miss the constraint failure for Y<Z> because according to the cached normal form, Y is not constrained. This patch fixes this issue by moving up the call to associate_classtype_constraints so that we set constraints before we start processing a class's bases. gcc/cp/ChangeLog: PR c++/96229 * parser.c (cp_parser_class_specifier_1): Move call to associate_classtype_constraints from here to ... (cp_parser_class_head): ... here. * pt.c (is_compatible_template_arg): Correct documentation to say "argument is _no_ more constrained than the parameter". gcc/testsuite/ChangeLog: PR c++/96229 * g++.dg/cpp2a/concepts-class2.C: New test.
prev parent reply other threads:[~2021-07-19 10:04 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-82833-4@http.gcc.gnu.org/bugzilla/> 2021-07-19 0:08 ` pinskia at gcc dot gnu.org 2021-07-19 10:04 ` redi at gcc dot gnu.org [this message]
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