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P0624R2 - Default constructible and assignable stateless lambdas

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P0624R2 - Default constructible and assignable stateless lambdas
	* method.c (synthesized_method_walk): For C++2a don't mark
	sfk_constructor or sfk_copy_assignment as deleted if lambda has
	no lambda-captures.

	* g++.dg/cpp2a/lambda1.C: New test.
	* g++.dg/cpp0x/lambda/lambda-ice2.C: Adjust expected diagnostics
	for -std=c++2a.

From-SVN: r261605
This commit is contained in:
Jakub Jelinek 2018-06-14 21:05:13 +02:00 • committed by Jakub Jelinek
parent 2d26d4ce69
commit bc04d1ff62
5 changed files with 85 additions and 8 deletions
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7
gcc/cp/ChangeLog
View file

@ -1,3 +1,10 @@
2018-06-14 Jakub Jelinek <jakub@redhat.com>
P0624R2 - Default constructible and assignable stateless lambdas
* method.c (synthesized_method_walk): For C++2a don't mark
sfk_constructor or sfk_copy_assignment as deleted if lambda has
no lambda-captures.
2018-06-14 Paolo Carlini <paolo.carlini@oracle.com>
* decl.c (duplicate_decls): Use DECL_SOURCE_LOCATION in

11
gcc/cp/method.c
View file

@ -1539,10 +1539,15 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
{
/* "The closure type associated with a lambda-expression has a deleted
default constructor and a deleted copy assignment operator."
This is diagnosed in maybe_explain_implicit_delete. */
This is diagnosed in maybe_explain_implicit_delete.
In C++2a, only lambda-expressions with lambda-captures have those
deleted. */
if (LAMBDA_TYPE_P (ctype)
&& (sfk == sfk_constructor
|| sfk == sfk_copy_assignment))
&& (sfk == sfk_constructor || sfk == sfk_copy_assignment)
&& (cxx_dialect < cxx2a
|| LAMBDA_EXPR_CAPTURE_LIST (CLASSTYPE_LAMBDA_EXPR (ctype))
|| LAMBDA_EXPR_DEFAULT_CAPTURE_MODE
(CLASSTYPE_LAMBDA_EXPR (ctype)) != CPLD_NONE))
{
*deleted_p = true;
return;

7
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,10 @@
2018-06-14 Jakub Jelinek <jakub@redhat.com>
P0624R2 - Default constructible and assignable stateless lambdas
* g++.dg/cpp2a/lambda1.C: New test.
* g++.dg/cpp0x/lambda/lambda-ice2.C: Adjust expected diagnostics
for -std=c++2a.
2018-06-14 Paolo Carlini <paolo.carlini@oracle.com>
* g++.dg/other/static3.C: New.

10
gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice2.C
View file

@ -2,15 +2,15 @@
// { dg-do compile { target c++11 } }
template<typename F>
decltype(F()) run(F f) // { dg-message "note" }
decltype(F()) run(F f) // { dg-message "note" "" { target c++17_down } }
{
return f();
return f(); // { dg-error "could not convert" "" { target c++2a } }
}
int main()
{
auto l = []() { return 5; }; // { dg-message "lambda closure type" }
auto l = []() { return 5; }; // { dg-message "lambda closure type" "" { target c++17_down } }
run(l); // { dg-error "no match" }
// { dg-error "use of deleted function" "candidate explanation" { target *-*-* } 5 }
run(l); // { dg-error "no match" "" { target c++17_down } }
// { dg-error "use of deleted function" "candidate explanation" { target c++17_down } 5 }
}

58
gcc/testsuite/g++.dg/cpp2a/lambda1.C Normal file
View file

@ -0,0 +1,58 @@
// P0624R2
// { dg-do compile { target c++11 } }
#if __cplusplus >= 201402L
#define A auto
#else
#define A int
#endif
void
f1 ()
{
auto greater = [](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" "" { target c++17_down } }
decltype (greater) gt; // { dg-error "use of deleted function" "" { target c++17_down } }
gt = greater; // { dg-error "use of deleted function" "" { target c++17_down } }
}
void
f2 ()
{
auto greater = [&](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" }
decltype (greater) gt; // { dg-error "use of deleted function" }
gt = greater; // { dg-error "use of deleted function" }
}
void
f3 ()
{
auto greater = [=](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" }
decltype (greater) gt; // { dg-error "use of deleted function" }
gt = greater; // { dg-error "use of deleted function" }
}
void
f4 (int i)
{
auto greater = [i](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" }
decltype (greater) gt; // { dg-error "use of deleted function" }
gt = greater; // { dg-error "use of deleted function" }
}
#if __cplusplus > 201703L
void
f5 ()
{
auto greater = [](auto x, auto y) constexpr { return x > y; };
decltype (greater) gt;
static_assert (!gt (1, 2));
static_assert (gt (4, 3));
static_assert (!gt (3.5, 3.75));
static_assert (gt (3.5, 3.25));
gt = greater;
static_assert (!gt (1, 2));
static_assert (gt (4, 3));
static_assert (!gt (3.5, 3.75));
static_assert (gt (3.5, 3.25));
}
#endif