diff options
Diffstat (limited to 'gcc/testsuite/g++.dg/cpp2a/class-deduction-alias1.C')
-rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/class-deduction-alias1.C | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias1.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias1.C new file mode 100644 index 00000000000..ed47eb38f1b --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias1.C @@ -0,0 +1,27 @@ +// 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 *>" } |