On 3/4/24 12:49, Marek Polacek wrote:
On Fri, Mar 01, 2024 at 07:58:24PM -0500, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for 15? (Or even trunk?)
-- >8 --
<https://wg21.link/p1381r1> clarifies that it's OK to capture structured
bindings.
[expr.prim.lambda.capture]/4 says "The identifier in a simple-capture shall
denote a local entity" and [basic.pre]/3: "An entity is a [...] structured
binding".
It doesn't appear that this was made a DR, so, strictly speaking, we
should have a -Wc++20-extensions warning, like clang++.
PR c++/85889
gcc/cp/ChangeLog:
* lambda.cc (add_capture): Add a pedwarn for capturing structured
bindings.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/decomp3.C: Use -Wno-c++20-extensions.
* g++.dg/cpp1z/decomp60.C: New test.
---
gcc/cp/lambda.cc | 9 +++++++++
gcc/testsuite/g++.dg/cpp1z/decomp60.C | 12 ++++++++++++
gcc/testsuite/g++.dg/cpp2a/decomp3.C | 2 +-
3 files changed, 22 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1z/decomp60.C
diff --git a/gcc/cp/lambda.cc b/gcc/cp/lambda.cc
index 4b1f9391fee..470f9d2c4f1 100644
--- a/gcc/cp/lambda.cc
+++ b/gcc/cp/lambda.cc
@@ -607,6 +607,15 @@ add_capture (tree lambda, tree id, tree orig_init, bool
by_reference_p,
TCTX_CAPTURE_BY_COPY, type))
return error_mark_node;
}
+
+ if (cxx_dialect < cxx20)
+ {
+ tree stripped_init = tree_strip_any_location_wrapper (initializer);
I was missing an auto_diagnostic_group here. Fixed.
OK for 15 with that fix.
+ if (DECL_DECOMPOSITION_P (stripped_init)
+ && pedwarn (input_location, OPT_Wc__20_extensions,
+ "captured structured bindings are a C++20 extension"))
+ inform (DECL_SOURCE_LOCATION (stripped_init), "declared here");
