@@ -1201,6 +1201,8 @@ is_xible_helper (enum tree_code code, tree to, tree from, bool trivial)
expr = assignable_expr (to, from);
else if (trivial && from && TREE_CHAIN (from))
return error_mark_node; // only 0- and 1-argument ctors can be trivial
+ else if (TREE_CODE(to) == ARRAY_TYPE && !TYPE_DOMAIN (to))
+ return error_mark_node; // can't construct an array of unknown bound
else
expr = constructible_expr (to, from);
return expr;
new file mode 100644
@@ -0,0 +1,27 @@
+// { dg-do compile { target c++11 } }
+// PR c++/90532
+static_assert( !__is_constructible(int[]), "" );
+static_assert( !__is_constructible(int[], int), "" );
+static_assert( !__is_constructible(int[], int[]), "" );
+static_assert( !__is_trivially_constructible(int[]), "" );
+static_assert( !__is_trivially_constructible(int[], int), "" );
+static_assert( !__is_trivially_constructible(int[], int[]), "" );
+static_assert( !__is_trivially_constructible(int[], int(&)[]), "" );
+static_assert( !__is_trivially_constructible(int[], void), "" );
+struct A { };
+static_assert( !__is_constructible(A[]), "" );
+static_assert( !__is_constructible(A[], const A&), "" );
+static_assert( !__is_constructible(A[], const A[]), "" );
+static_assert( !__is_trivially_constructible(A[]), "" );
+static_assert( !__is_trivially_constructible(A[], const A&), "" );
+static_assert( !__is_trivially_constructible(A[], const A[]), "" );
+static_assert( !__is_trivially_constructible(A[], A(&)[]), "" );
+static_assert( !__is_trivially_constructible(A[], void), "" );
+struct B { B(); };
+static_assert( !__is_constructible(B[]), "" );
+static_assert( !__is_constructible(B[], const B&), "" );
+static_assert( !__is_trivially_constructible(B[]), "" );
+static_assert( !__is_trivially_constructible(B[], const B&), "" );
+static_assert( !__is_trivially_constructible(B[], const B[]), "" );
+static_assert( !__is_trivially_constructible(B[], B(&)[]), "" );
+static_assert( !__is_trivially_constructible(B[], void), "" );
@@ -878,58 +878,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: public __is_nt_destructible_safe<_Tp>::type
{ };
- struct __do_is_default_constructible_impl
- {
- template<typename _Tp, typename = decltype(_Tp())>
- static true_type __test(int);
-
- template<typename>
- static false_type __test(...);
- };
-
- template<typename _Tp>
- struct __is_default_constructible_impl
- : public __do_is_default_constructible_impl
- {
- typedef decltype(__test<_Tp>(0)) type;
- };
-
- template<typename _Tp>
- struct __is_default_constructible_atom
- : public __and_<__not_<is_void<_Tp>>,
- __is_default_constructible_impl<_Tp>>
- { };
-
- template<typename _Tp, bool = is_array<_Tp>::value>
- struct __is_default_constructible_safe;
-
- // The following technique is a workaround for a current core language
- // restriction, which does not allow for array types to occur in
- // functional casts of the form T(). Complete arrays can be default-
- // constructed, if the element type is default-constructible, but
- // arrays with unknown bounds are not.
- template<typename _Tp>
- struct __is_default_constructible_safe<_Tp, true>
- : public __and_<__is_array_known_bounds<_Tp>,
- __is_default_constructible_atom<typename
- remove_all_extents<_Tp>::type>>
- { };
-
- template<typename _Tp>
- struct __is_default_constructible_safe<_Tp, false>
- : public __is_default_constructible_atom<_Tp>::type
+ /// is_constructible
+ template<typename _Tp, typename... _Args>
+ struct is_constructible
+ : public __bool_constant<__is_constructible(_Tp, _Args...)>
{ };
/// is_default_constructible
template<typename _Tp>
struct is_default_constructible
- : public __is_default_constructible_safe<_Tp>::type
- { };
-
- /// is_constructible
- template<typename _Tp, typename... _Args>
- struct is_constructible
- : public __bool_constant<__is_constructible(_Tp, _Args...)>
+ : public is_constructible<_Tp>::type
{ };
template<typename _Tp, bool = __is_referenceable<_Tp>::value>
@@ -35,4 +35,11 @@ void test01()
static_assert(test_property<is_constructible, ExplicitClass>(false), "");
static_assert(test_property<is_constructible, ExplicitClass,
int, double>(false), "");
+ static_assert(test_property<is_constructible, int[]>(false), "PR c++/90532");
+ static_assert(test_property<is_constructible,
+ __gnu_test::construct::Empty[]>(false), "PR c++/90532");
+ static_assert(test_property<is_constructible,
+ __gnu_test::construct::Ukn[]>(false), "PR c++/90532");
+ static_assert(test_property<is_constructible,
+ __gnu_test::construct::nAny[]>(false), "PR c++/90532");
}
@@ -138,3 +138,13 @@ static_assert(!std::is_default_constructible<DelCopy>::value, "Error");
static_assert(!std::is_default_constructible<const DelCopy>::value, "Error");
static_assert(!std::is_default_constructible<DelDtor>::value, "Error");
static_assert(!std::is_default_constructible<const DelDtor>::value, "Error");
+
+static_assert(!std::is_default_constructible<int[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<Empty[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<B[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<D[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<U[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<Ukn[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<Ellipsis[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<Any[]>::value, "PR c++/90532");
+static_assert(!std::is_default_constructible<nAny[]>::value, "PR c++/90532");
@@ -180,4 +180,6 @@ void test01()
MoveOnly, const MoveOnly&>(false), "");
static_assert(test_property<is_trivially_constructible,
MoveOnly2>(false), "");
+ static_assert(test_property<is_trivially_constructible,
+ int[]>(false), "PR c++/90532");
}
@@ -62,4 +62,13 @@ void test01()
construct::Nontrivial>(false), "");
static_assert(test_category<is_trivially_default_constructible,
HasTemplateCtor>(true), "");
+
+ static_assert(test_category<is_trivially_default_constructible,
+ int[]>(false), "PR c++/90532");
+ struct A { };
+ static_assert(test_category<is_trivially_default_constructible,
+ A[]>(false), "PR c++/90532");
+ struct B { B() { } };
+ static_assert(test_category<is_trivially_default_constructible,
+ B[]>(false), "PR c++/90532");
}
An array of an unknown bound is an incomplete type, so no object of such a type can be constructed. This means __is_constructible should always be false for an array of unknown bound. This patch also changes the std::is_default_constructible trait to use std::is_constructible, which now gives the right answer for arrays of unknown bound. gcc/cp: PR c++/90532 Ensure __is_constructible(T[]) is false * method.c (is_xible_helper): Return error_mark_node for construction of an array of unknown bound. gcc/testsuite: PR c++/90532 Ensure __is_constructible(T[]) is false * g++.dg/ext/90532.C: New test. libstdc++-v3: PR c++/90532 Ensure __is_constructible(T[]) is false * include/std/type_traits (__do_is_default_constructible_impl) (__is_default_constructible_atom, __is_default_constructible_safe): Remove. (is_default_constructible): Use is_constructible. * testsuite/20_util/is_constructible/value.cc: Check int[] case. * testsuite/20_util/is_default_constructible/value.cc: Likewise. * testsuite/20_util/is_trivially_constructible/value.cc: Likewise. * testsuite/20_util/is_trivially_default_constructible/value.cc: Likewise. Tested powerpc64le-linux. Is the G++ change OK for trunk? This fixes a regression on gcc-9-branch and gcc-8-branch, because changing std::is_constructible to use __is_constructible caused it to start giving the wrong answer for arrays of unknown bound. OK for the branches too, after appropriate testing? commit 7345fea9bc28c0c7bd5d9e72a5f97341e6c0e4c2 Author: Jonathan Wakely <jwakely@redhat.com> Date: Mon May 20 10:13:19 2019 +0100 PR c++/90532 Ensure __is_constructible(T[]) is false An array of an unknown bound is an incomplete type, so no object of such a type can be constructed. This means __is_constructible should always be false for an array of unknown bound. This patch also changes the std::is_default_constructible trait to use std::is_constructible, which now gives the right answer for arrays of unknown bound. gcc/cp: PR c++/90532 Ensure __is_constructible(T[]) is false * method.c (is_xible_helper): Return error_mark_node for construction of an array of unknown bound. gcc/testsuite: PR c++/90532 Ensure __is_constructible(T[]) is false * g++.dg/ext/90532.C: New test. libstdc++-v3: PR c++/90532 Ensure __is_constructible(T[]) is false * include/std/type_traits (__do_is_default_constructible_impl) (__is_default_constructible_atom, __is_default_constructible_safe): Remove. (is_default_constructible): Use is_constructible. * testsuite/20_util/is_constructible/value.cc: Check int[] case. * testsuite/20_util/is_default_constructible/value.cc: Likewise. * testsuite/20_util/is_trivially_constructible/value.cc: Likewise. * testsuite/20_util/is_trivially_default_constructible/value.cc: Likewise.