Mercurial > hg > CbC > CbC_gcc
view gcc/testsuite/g++.dg/cpp2a/class-deduction-alias1.C @ 145:1830386684a0
gcc-9.2.0
author | anatofuz |
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date | Thu, 13 Feb 2020 11:34:05 +0900 |
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// Testcase from P1814R0 // { dg-do compile { target c++2a } } template <class T> struct identity { using type = T; }; template <class T> using identity_t = typename identity<T>::type; template <class T> concept Int = __is_same_as (T, int); template <class T, class U> struct C { C(T, U); // #1 { dg-message "constraint" } }; template<class T, class U> C(T, U) -> C<T, identity_t<U>>; // #2 { dg-message "constraint" } template<class V> using A = C<V *, V *>; template<Int W> using B = A<W>; int i{}; double d{}; A a1(&i, &i); // { dg-bogus "" "Deduces A<int>" } A a2(i, i); // { dg-error "" "cannot deduce V * from i" } A a3(&i, &d); // { dg-error "" } #1: Cannot deduce (V*, V*) from (int *, double *) // #2: Cannot deduce A<V> from C<int *, double *> B b1(&i, &i); // { dg-bogus "" "Deduces B<int>" } B b2(&d, &d); // { dg-error "" "cannot deduce B<W> from C<double *, double *>" }