From e6a1e5fe7346458208ede97741382061a6191024 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Mon, 13 Aug 2018 15:46:42 +0000 Subject: [PATCH] P0806R2 - Deprecate implicit capture of this via [=] P0806R2 - Deprecate implicit capture of this via [=] * lambda.c (add_default_capture): Formatting fixes. Warn about deprecated implicit capture of this via [=]. * g++.dg/cpp2a/lambda-this1.C: New test. * g++.dg/cpp2a/lambda-this2.C: New test. * g++.dg/cpp2a/lambda-this3.C: New test. From-SVN: r263508 --- gcc/cp/ChangeLog | 4 ++ gcc/cp/lambda.c | 19 +++++--- gcc/testsuite/ChangeLog | 7 +++ gcc/testsuite/g++.dg/cpp2a/lambda-this1.C | 51 +++++++++++++++++++++ gcc/testsuite/g++.dg/cpp2a/lambda-this2.C | 51 +++++++++++++++++++++ gcc/testsuite/g++.dg/cpp2a/lambda-this3.C | 55 +++++++++++++++++++++++ 6 files changed, 182 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/lambda-this1.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/lambda-this2.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/lambda-this3.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 859085be4ca..da6703b304c 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,9 @@ 2018-08-13 Marek Polacek + P0806R2 - Deprecate implicit capture of this via [=] + * lambda.c (add_default_capture): Formatting fixes. Warn about + deprecated implicit capture of this via [=]. + PR c++/86915 * decl.c (create_array_type_for_decl): Handle null name. diff --git a/gcc/cp/lambda.c b/gcc/cp/lambda.c index 54fc3ee85c3..25a4d6f7eef 100644 --- a/gcc/cp/lambda.c +++ b/gcc/cp/lambda.c @@ -695,14 +695,10 @@ tree add_default_capture (tree lambda_stack, tree id, tree initializer) { bool this_capture_p = (id == this_identifier); - tree var = NULL_TREE; - tree saved_class_type = current_class_type; - tree node; - - for (node = lambda_stack; + for (tree node = lambda_stack; node; node = TREE_CHAIN (node)) { @@ -720,6 +716,19 @@ add_default_capture (tree lambda_stack, tree id, tree initializer) == CPLD_REFERENCE)), /*explicit_init_p=*/false); initializer = convert_from_reference (var); + + /* Warn about deprecated implicit capture of this via [=]. */ + if (cxx_dialect >= cxx2a + && this_capture_p + && LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) == CPLD_COPY + && !in_system_header_at (LAMBDA_EXPR_LOCATION (lambda))) + { + if (warning_at (LAMBDA_EXPR_LOCATION (lambda), OPT_Wdeprecated, + "implicit capture of %qE via %<[=]%> is deprecated " + "in C++20", this_identifier)) + inform (LAMBDA_EXPR_LOCATION (lambda), "add explicit % or " + "%<*this%> capture"); + } } current_class_type = saved_class_type; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index c11b5c89af1..d7ed84edacf 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2018-08-13 Marek Polacek + + P0806R2 - Deprecate implicit capture of this via [=] + * g++.dg/cpp2a/lambda-this1.C: New test. + * g++.dg/cpp2a/lambda-this2.C: New test. + * g++.dg/cpp2a/lambda-this3.C: New test. + 2018-08-13 Marek Polacek PR c++/86915 diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-this1.C b/gcc/testsuite/g++.dg/cpp2a/lambda-this1.C new file mode 100644 index 00000000000..a31b968800d --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/lambda-this1.C @@ -0,0 +1,51 @@ +// P0806R2 +// { dg-do compile } +// { dg-options "-std=c++2a" } + +struct X { + int x; + void foo (int n) { + auto a1 = [=] { x = n; }; // { dg-warning "implicit capture" } + auto a2 = [=, this] { x = n; }; + auto a3 = [=, *this]() mutable { x = n; }; + auto a4 = [&] { x = n; }; + auto a5 = [&, this] { x = n; }; + auto a6 = [&, *this]() mutable { x = n; }; + + auto a7 = [=] { // { dg-warning "implicit capture" } + auto a = [=] { // { dg-warning "implicit capture" } + auto a2 = [=] { x = n; }; // { dg-warning "implicit capture" } + }; + }; + + auto a8 = [=, this] { + auto a = [=, this] { + auto a2 = [=, this] { x = n; }; + }; + }; + + auto a9 = [=, *this]() mutable { + auto a = [=, *this]() mutable { + auto a2 = [=, *this]() mutable { x = n; }; + }; + }; + + auto a10 = [&] { + auto a = [&] { + auto a2 = [&] { x = n; }; + }; + }; + + auto a11 = [&, this] { + auto a = [&, this] { + auto a2 = [&, this] { x = n; }; + }; + }; + + auto a12 = [&, *this]() mutable { + auto a = [&, *this]() mutable { + auto a2 = [&, *this]() mutable { x = n; }; + }; + }; + } +}; diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-this2.C b/gcc/testsuite/g++.dg/cpp2a/lambda-this2.C new file mode 100644 index 00000000000..307fb4c31db --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/lambda-this2.C @@ -0,0 +1,51 @@ +// P0806R2 +// { dg-do compile } +// { dg-options "-std=c++2a -Wno-deprecated" } + +struct X { + int x; + void foo (int n) { + auto a1 = [=] { x = n; }; // { dg-bogus "implicit capture" } + auto a2 = [=, this] { x = n; }; + auto a3 = [=, *this]() mutable { x = n; }; + auto a4 = [&] { x = n; }; + auto a5 = [&, this] { x = n; }; + auto a6 = [&, *this]() mutable { x = n; }; + + auto a7 = [=] { // { dg-bogus "implicit capture" } + auto a = [=] { // { dg-bogus "implicit capture" } + auto a2 = [=] { x = n; }; // { dg-bogus "implicit capture" } + }; + }; + + auto a8 = [=, this] { + auto a = [=, this] { + auto a2 = [=, this] { x = n; }; + }; + }; + + auto a9 = [=, *this]() mutable { + auto a = [=, *this]() mutable { + auto a2 = [=, *this]() mutable { x = n; }; + }; + }; + + auto a10 = [&] { + auto a = [&] { + auto a2 = [&] { x = n; }; + }; + }; + + auto a11 = [&, this] { + auto a = [&, this] { + auto a2 = [&, this] { x = n; }; + }; + }; + + auto a12 = [&, *this]() mutable { + auto a = [&, *this]() mutable { + auto a2 = [&, *this]() mutable { x = n; }; + }; + }; + } +}; diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-this3.C b/gcc/testsuite/g++.dg/cpp2a/lambda-this3.C new file mode 100644 index 00000000000..5e5c8b3d50f --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/lambda-this3.C @@ -0,0 +1,55 @@ +// P0806R2 +// { dg-do compile } +// { dg-options "-std=c++17" } + +struct X { + int x; + void foo (int n) { + auto a1 = [=] { x = n; }; // { dg-bogus "implicit capture" } + auto a2 = [=, this] { x = n; }; + // { dg-warning "explicit by-copy capture" "" { target c++17_down } .-1 } + auto a3 = [=, *this]() mutable { x = n; }; + auto a4 = [&] { x = n; }; + auto a5 = [&, this] { x = n; }; + auto a6 = [&, *this]() mutable { x = n; }; + + auto a7 = [=] { // { dg-bogus "implicit capture" } + auto a = [=] { // { dg-bogus "implicit capture" } + auto a2 = [=] { x = n; }; // { dg-bogus "implicit capture" } + }; + }; + + auto a8 = [=, this] { + // { dg-warning "explicit by-copy capture" "" { target c++17_down } .-1 } + auto a = [=, this] { + // { dg-warning "explicit by-copy capture" "" { target c++17_down } .-1 } + auto a2 = [=, this] { x = n; }; + // { dg-warning "explicit by-copy capture" "" { target c++17_down } .-1 } + }; + }; + + auto a9 = [=, *this]() mutable { + auto a = [=, *this]() mutable { + auto a2 = [=, *this]() mutable { x = n; }; + }; + }; + + auto a10 = [&] { + auto a = [&] { + auto a2 = [&] { x = n; }; + }; + }; + + auto a11 = [&, this] { + auto a = [&, this] { + auto a2 = [&, this] { x = n; }; + }; + }; + + auto a12 = [&, *this]() mutable { + auto a = [&, *this]() mutable { + auto a2 = [&, *this]() mutable { x = n; }; + }; + }; + } +}; -- 2.30.2